Update gitea-vet to v0.2.1 (#12282)

* change to new code location

* vendor

* tagged version v0.2.0

* gitea-vet v0.2.1

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

vendor/golang.org/x/tools/internal/analysisinternal/analysis.go

@@ -0,0 +1,421 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package analysisinternal exposes internal-only fields from go/analysis.
+package analysisinternal
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+	"strings"
+
+	"golang.org/x/tools/go/ast/astutil"
+	"golang.org/x/tools/internal/lsp/fuzzy"
+)
+
+var (
+	GetTypeErrors func(p interface{}) []types.Error
+	SetTypeErrors func(p interface{}, errors []types.Error)
+)
+
+func TypeErrorEndPos(fset *token.FileSet, src []byte, start token.Pos) token.Pos {
+	// Get the end position for the type error.
+	offset, end := fset.PositionFor(start, false).Offset, start
+	if offset >= len(src) {
+		return end
+	}
+	if width := bytes.IndexAny(src[offset:], " \n,():;[]+-*"); width > 0 {
+		end = start + token.Pos(width)
+	}
+	return end
+}
+
+func ZeroValue(fset *token.FileSet, f *ast.File, pkg *types.Package, typ types.Type) ast.Expr {
+	under := typ
+	if n, ok := typ.(*types.Named); ok {
+		under = n.Underlying()
+	}
+	switch u := under.(type) {
+	case *types.Basic:
+		switch {
+		case u.Info()&types.IsNumeric != 0:
+			return &ast.BasicLit{Kind: token.INT, Value: "0"}
+		case u.Info()&types.IsBoolean != 0:
+			return &ast.Ident{Name: "false"}
+		case u.Info()&types.IsString != 0:
+			return &ast.BasicLit{Kind: token.STRING, Value: `""`}
+		default:
+			panic("unknown basic type")
+		}
+	case *types.Chan, *types.Interface, *types.Map, *types.Pointer, *types.Signature, *types.Slice, *types.Array:
+		return ast.NewIdent("nil")
+	case *types.Struct:
+		texpr := TypeExpr(fset, f, pkg, typ) // typ because we want the name here.
+		if texpr == nil {
+			return nil
+		}
+		return &ast.CompositeLit{
+			Type: texpr,
+		}
+	}
+	return nil
+}
+
+// IsZeroValue checks whether the given expression is a 'zero value' (as determined by output of
+// analysisinternal.ZeroValue)
+func IsZeroValue(expr ast.Expr) bool {
+	switch e := expr.(type) {
+	case *ast.BasicLit:
+		return e.Value == "0" || e.Value == `""`
+	case *ast.Ident:
+		return e.Name == "nil" || e.Name == "false"
+	default:
+		return false
+	}
+}
+
+func TypeExpr(fset *token.FileSet, f *ast.File, pkg *types.Package, typ types.Type) ast.Expr {
+	switch t := typ.(type) {
+	case *types.Basic:
+		switch t.Kind() {
+		case types.UnsafePointer:
+			return &ast.SelectorExpr{X: ast.NewIdent("unsafe"), Sel: ast.NewIdent("Pointer")}
+		default:
+			return ast.NewIdent(t.Name())
+		}
+	case *types.Pointer:
+		x := TypeExpr(fset, f, pkg, t.Elem())
+		if x == nil {
+			return nil
+		}
+		return &ast.UnaryExpr{
+			Op: token.MUL,
+			X:  x,
+		}
+	case *types.Array:
+		elt := TypeExpr(fset, f, pkg, t.Elem())
+		if elt == nil {
+			return nil
+		}
+		return &ast.ArrayType{
+			Len: &ast.BasicLit{
+				Kind:  token.INT,
+				Value: fmt.Sprintf("%d", t.Len()),
+			},
+			Elt: elt,
+		}
+	case *types.Slice:
+		elt := TypeExpr(fset, f, pkg, t.Elem())
+		if elt == nil {
+			return nil
+		}
+		return &ast.ArrayType{
+			Elt: elt,
+		}
+	case *types.Map:
+		key := TypeExpr(fset, f, pkg, t.Key())
+		value := TypeExpr(fset, f, pkg, t.Elem())
+		if key == nil || value == nil {
+			return nil
+		}
+		return &ast.MapType{
+			Key:   key,
+			Value: value,
+		}
+	case *types.Chan:
+		dir := ast.ChanDir(t.Dir())
+		if t.Dir() == types.SendRecv {
+			dir = ast.SEND | ast.RECV
+		}
+		value := TypeExpr(fset, f, pkg, t.Elem())
+		if value == nil {
+			return nil
+		}
+		return &ast.ChanType{
+			Dir:   dir,
+			Value: value,
+		}
+	case *types.Signature:
+		var params []*ast.Field
+		for i := 0; i < t.Params().Len(); i++ {
+			p := TypeExpr(fset, f, pkg, t.Params().At(i).Type())
+			if p == nil {
+				return nil
+			}
+			params = append(params, &ast.Field{
+				Type: p,
+				Names: []*ast.Ident{
+					{
+						Name: t.Params().At(i).Name(),
+					},
+				},
+			})
+		}
+		var returns []*ast.Field
+		for i := 0; i < t.Results().Len(); i++ {
+			r := TypeExpr(fset, f, pkg, t.Results().At(i).Type())
+			if r == nil {
+				return nil
+			}
+			returns = append(returns, &ast.Field{
+				Type: r,
+			})
+		}
+		return &ast.FuncType{
+			Params: &ast.FieldList{
+				List: params,
+			},
+			Results: &ast.FieldList{
+				List: returns,
+			},
+		}
+	case *types.Named:
+		if t.Obj().Pkg() == nil {
+			return ast.NewIdent(t.Obj().Name())
+		}
+		if t.Obj().Pkg() == pkg {
+			return ast.NewIdent(t.Obj().Name())
+		}
+		pkgName := t.Obj().Pkg().Name()
+		// If the file already imports the package under another name, use that.
+		for _, group := range astutil.Imports(fset, f) {
+			for _, cand := range group {
+				if strings.Trim(cand.Path.Value, `"`) == t.Obj().Pkg().Path() {
+					if cand.Name != nil && cand.Name.Name != "" {
+						pkgName = cand.Name.Name
+					}
+				}
+			}
+		}
+		if pkgName == "." {
+			return ast.NewIdent(t.Obj().Name())
+		}
+		return &ast.SelectorExpr{
+			X:   ast.NewIdent(pkgName),
+			Sel: ast.NewIdent(t.Obj().Name()),
+		}
+	default:
+		return nil // TODO: anonymous structs, but who does that
+	}
+}
+
+type TypeErrorPass string
+
+const (
+	NoNewVars      TypeErrorPass = "nonewvars"
+	NoResultValues TypeErrorPass = "noresultvalues"
+	UndeclaredName TypeErrorPass = "undeclaredname"
+)
+
+// StmtToInsertVarBefore returns the ast.Stmt before which we can safely insert a new variable.
+// Some examples:
+//
+// Basic Example:
+// z := 1
+// y := z + x
+// If x is undeclared, then this function would return `y := z + x`, so that we
+// can insert `x := ` on the line before `y := z + x`.
+//
+// If stmt example:
+// if z == 1 {
+// } else if z == y {}
+// If y is undeclared, then this function would return `if z == 1 {`, because we cannot
+// insert a statement between an if and an else if statement. As a result, we need to find
+// the top of the if chain to insert `y := ` before.
+func StmtToInsertVarBefore(path []ast.Node) ast.Stmt {
+	enclosingIndex := -1
+	for i, p := range path {
+		if _, ok := p.(ast.Stmt); ok {
+			enclosingIndex = i
+			break
+		}
+	}
+	if enclosingIndex == -1 {
+		return nil
+	}
+	enclosingStmt := path[enclosingIndex]
+	switch enclosingStmt.(type) {
+	case *ast.IfStmt:
+		// The enclosingStmt is inside of the if declaration,
+		// We need to check if we are in an else-if stmt and
+		// get the base if statement.
+		return baseIfStmt(path, enclosingIndex)
+	case *ast.CaseClause:
+		// Get the enclosing switch stmt if the enclosingStmt is
+		// inside of the case statement.
+		for i := enclosingIndex + 1; i < len(path); i++ {
+			if node, ok := path[i].(*ast.SwitchStmt); ok {
+				return node
+			} else if node, ok := path[i].(*ast.TypeSwitchStmt); ok {
+				return node
+			}
+		}
+	}
+	if len(path) <= enclosingIndex+1 {
+		return enclosingStmt.(ast.Stmt)
+	}
+	// Check if the enclosing statement is inside another node.
+	switch expr := path[enclosingIndex+1].(type) {
+	case *ast.IfStmt:
+		// Get the base if statement.
+		return baseIfStmt(path, enclosingIndex+1)
+	case *ast.ForStmt:
+		if expr.Init == enclosingStmt || expr.Post == enclosingStmt {
+			return expr
+		}
+	}
+	return enclosingStmt.(ast.Stmt)
+}
+
+// baseIfStmt walks up the if/else-if chain until we get to
+// the top of the current if chain.
+func baseIfStmt(path []ast.Node, index int) ast.Stmt {
+	stmt := path[index]
+	for i := index + 1; i < len(path); i++ {
+		if node, ok := path[i].(*ast.IfStmt); ok && node.Else == stmt {
+			stmt = node
+			continue
+		}
+		break
+	}
+	return stmt.(ast.Stmt)
+}
+
+// WalkASTWithParent walks the AST rooted at n. The semantics are
+// similar to ast.Inspect except it does not call f(nil).
+func WalkASTWithParent(n ast.Node, f func(n ast.Node, parent ast.Node) bool) {
+	var ancestors []ast.Node
+	ast.Inspect(n, func(n ast.Node) (recurse bool) {
+		if n == nil {
+			ancestors = ancestors[:len(ancestors)-1]
+			return false
+		}
+
+		var parent ast.Node
+		if len(ancestors) > 0 {
+			parent = ancestors[len(ancestors)-1]
+		}
+		ancestors = append(ancestors, n)
+		return f(n, parent)
+	})
+}
+
+// FindMatchingIdents finds all identifiers in 'node' that match any of the given types.
+// 'pos' represents the position at which the identifiers may be inserted. 'pos' must be within
+// the scope of each of identifier we select. Otherwise, we will insert a variable at 'pos' that
+// is unrecognized.
+func FindMatchingIdents(typs []types.Type, node ast.Node, pos token.Pos, info *types.Info, pkg *types.Package) map[types.Type][]*ast.Ident {
+	matches := map[types.Type][]*ast.Ident{}
+	// Initialize matches to contain the variable types we are searching for.
+	for _, typ := range typs {
+		if typ == nil {
+			continue
+		}
+		matches[typ] = []*ast.Ident{}
+	}
+	seen := map[types.Object]struct{}{}
+	ast.Inspect(node, func(n ast.Node) bool {
+		if n == nil {
+			return false
+		}
+		// Prevent circular definitions. If 'pos' is within an assignment statement, do not
+		// allow any identifiers in that assignment statement to be selected. Otherwise,
+		// we could do the following, where 'x' satisfies the type of 'f0':
+		//
+		// x := fakeStruct{f0: x}
+		//
+		assignment, ok := n.(*ast.AssignStmt)
+		if ok && pos > assignment.Pos() && pos <= assignment.End() {
+			return false
+		}
+		if n.End() > pos {
+			return n.Pos() <= pos
+		}
+		ident, ok := n.(*ast.Ident)
+		if !ok || ident.Name == "_" {
+			return true
+		}
+		obj := info.Defs[ident]
+		if obj == nil || obj.Type() == nil {
+			return true
+		}
+		if _, ok := obj.(*types.TypeName); ok {
+			return true
+		}
+		// Prevent duplicates in matches' values.
+		if _, ok = seen[obj]; ok {
+			return true
+		}
+		seen[obj] = struct{}{}
+		// Find the scope for the given position. Then, check whether the object
+		// exists within the scope.
+		innerScope := pkg.Scope().Innermost(pos)
+		if innerScope == nil {
+			return true
+		}
+		_, foundObj := innerScope.LookupParent(ident.Name, pos)
+		if foundObj != obj {
+			return true
+		}
+		// The object must match one of the types that we are searching for.
+		if idents, ok := matches[obj.Type()]; ok {
+			matches[obj.Type()] = append(idents, ast.NewIdent(ident.Name))
+		}
+		// If the object type does not exactly match any of the target types, greedily
+		// find the first target type that the object type can satisfy.
+		for typ := range matches {
+			if obj.Type() == typ {
+				continue
+			}
+			if equivalentTypes(obj.Type(), typ) {
+				matches[typ] = append(matches[typ], ast.NewIdent(ident.Name))
+			}
+		}
+		return true
+	})
+	return matches
+}
+
+func equivalentTypes(want, got types.Type) bool {
+	if want == got || types.Identical(want, got) {
+		return true
+	}
+	// Code segment to help check for untyped equality from (golang/go#32146).
+	if rhs, ok := want.(*types.Basic); ok && rhs.Info()&types.IsUntyped > 0 {
+		if lhs, ok := got.Underlying().(*types.Basic); ok {
+			return rhs.Info()&types.IsConstType == lhs.Info()&types.IsConstType
+		}
+	}
+	return types.AssignableTo(want, got)
+}
+
+// FindBestMatch employs fuzzy matching to evaluate the similarity of each given identifier to the
+// given pattern. We return the identifier whose name is most similar to the pattern.
+func FindBestMatch(pattern string, idents []*ast.Ident) ast.Expr {
+	fuzz := fuzzy.NewMatcher(pattern)
+	var bestFuzz ast.Expr
+	highScore := float32(-1) // minimum score is -1 (no match)
+	for _, ident := range idents {
+		// TODO: Improve scoring algorithm.
+		score := fuzz.Score(ident.Name)
+		if score > highScore {
+			highScore = score
+			bestFuzz = ident
+		} else if score == -1 {
+			// Order matters in the fuzzy matching algorithm. If we find no match
+			// when matching the target to the identifier, try matching the identifier
+			// to the target.
+			revFuzz := fuzzy.NewMatcher(ident.Name)
+			revScore := revFuzz.Score(pattern)
+			if revScore > highScore {
+				highScore = revScore
+				bestFuzz = ident
+			}
+		}
+	}
+	return bestFuzz
+}

vendor/golang.org/x/tools/internal/event/core/event.go

@@ -0,0 +1,85 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package core provides support for event based telemetry.
+package core
+
+import (
+	"fmt"
+	"time"
+
+	"golang.org/x/tools/internal/event/label"
+)
+
+// Event holds the information about an event of note that ocurred.
+type Event struct {
+	at time.Time
+
+	// As events are often on the stack, storing the first few labels directly
+	// in the event can avoid an allocation at all for the very common cases of
+	// simple events.
+	// The length needs to be large enough to cope with the majority of events
+	// but no so large as to cause undue stack pressure.
+	// A log message with two values will use 3 labels (one for each value and
+	// one for the message itself).
+
+	static  [3]label.Label // inline storage for the first few labels
+	dynamic []label.Label  // dynamically sized storage for remaining labels
+}
+
+// eventLabelMap implements label.Map for a the labels of an Event.
+type eventLabelMap struct {
+	event Event
+}
+
+func (ev Event) At() time.Time { return ev.at }
+
+func (ev Event) Format(f fmt.State, r rune) {
+	if !ev.at.IsZero() {
+		fmt.Fprint(f, ev.at.Format("2006/01/02 15:04:05 "))
+	}
+	for index := 0; ev.Valid(index); index++ {
+		if l := ev.Label(index); l.Valid() {
+			fmt.Fprintf(f, "\n\t%v", l)
+		}
+	}
+}
+
+func (ev Event) Valid(index int) bool {
+	return index >= 0 && index < len(ev.static)+len(ev.dynamic)
+}
+
+func (ev Event) Label(index int) label.Label {
+	if index < len(ev.static) {
+		return ev.static[index]
+	}
+	return ev.dynamic[index-len(ev.static)]
+}
+
+func (ev Event) Find(key label.Key) label.Label {
+	for _, l := range ev.static {
+		if l.Key() == key {
+			return l
+		}
+	}
+	for _, l := range ev.dynamic {
+		if l.Key() == key {
+			return l
+		}
+	}
+	return label.Label{}
+}
+
+func MakeEvent(static [3]label.Label, labels []label.Label) Event {
+	return Event{
+		static:  static,
+		dynamic: labels,
+	}
+}
+
+// CloneEvent event returns a copy of the event with the time adjusted to at.
+func CloneEvent(ev Event, at time.Time) Event {
+	ev.at = at
+	return ev
+}

vendor/golang.org/x/tools/internal/event/core/export.go

@@ -0,0 +1,70 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package core
+
+import (
+	"context"
+	"sync/atomic"
+	"time"
+	"unsafe"
+
+	"golang.org/x/tools/internal/event/label"
+)
+
+// Exporter is a function that handles events.
+// It may return a modified context and event.
+type Exporter func(context.Context, Event, label.Map) context.Context
+
+var (
+	exporter unsafe.Pointer
+)
+
+// SetExporter sets the global exporter function that handles all events.
+// The exporter is called synchronously from the event call site, so it should
+// return quickly so as not to hold up user code.
+func SetExporter(e Exporter) {
+	p := unsafe.Pointer(&e)
+	if e == nil {
+		// &e is always valid, and so p is always valid, but for the early abort
+		// of ProcessEvent to be efficient it needs to make the nil check on the
+		// pointer without having to dereference it, so we make the nil function
+		// also a nil pointer
+		p = nil
+	}
+	atomic.StorePointer(&exporter, p)
+}
+
+// deliver is called to deliver an event to the supplied exporter.
+// it will fill in the time.
+func deliver(ctx context.Context, exporter Exporter, ev Event) context.Context {
+	// add the current time to the event
+	ev.at = time.Now()
+	// hand the event off to the current exporter
+	return exporter(ctx, ev, ev)
+}
+
+// Export is called to deliver an event to the global exporter if set.
+func Export(ctx context.Context, ev Event) context.Context {
+	// get the global exporter and abort early if there is not one
+	exporterPtr := (*Exporter)(atomic.LoadPointer(&exporter))
+	if exporterPtr == nil {
+		return ctx
+	}
+	return deliver(ctx, *exporterPtr, ev)
+}
+
+// ExportPair is called to deliver a start event to the supplied exporter.
+// It also returns a function that will deliver the end event to the same
+// exporter.
+// It will fill in the time.
+func ExportPair(ctx context.Context, begin, end Event) (context.Context, func()) {
+	// get the global exporter and abort early if there is not one
+	exporterPtr := (*Exporter)(atomic.LoadPointer(&exporter))
+	if exporterPtr == nil {
+		return ctx, func() {}
+	}
+	ctx = deliver(ctx, *exporterPtr, begin)
+	return ctx, func() { deliver(ctx, *exporterPtr, end) }
+}

vendor/golang.org/x/tools/internal/event/core/fast.go

@@ -0,0 +1,77 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package core
+
+import (
+	"context"
+
+	"golang.org/x/tools/internal/event/keys"
+	"golang.org/x/tools/internal/event/label"
+)
+
+// Log1 takes a message and one label delivers a log event to the exporter.
+// It is a customized version of Print that is faster and does no allocation.
+func Log1(ctx context.Context, message string, t1 label.Label) {
+	Export(ctx, MakeEvent([3]label.Label{
+		keys.Msg.Of(message),
+		t1,
+	}, nil))
+}
+
+// Log2 takes a message and two labels and delivers a log event to the exporter.
+// It is a customized version of Print that is faster and does no allocation.
+func Log2(ctx context.Context, message string, t1 label.Label, t2 label.Label) {
+	Export(ctx, MakeEvent([3]label.Label{
+		keys.Msg.Of(message),
+		t1,
+		t2,
+	}, nil))
+}
+
+// Metric1 sends a label event to the exporter with the supplied labels.
+func Metric1(ctx context.Context, t1 label.Label) context.Context {
+	return Export(ctx, MakeEvent([3]label.Label{
+		keys.Metric.New(),
+		t1,
+	}, nil))
+}
+
+// Metric2 sends a label event to the exporter with the supplied labels.
+func Metric2(ctx context.Context, t1, t2 label.Label) context.Context {
+	return Export(ctx, MakeEvent([3]label.Label{
+		keys.Metric.New(),
+		t1,
+		t2,
+	}, nil))
+}
+
+// Start1 sends a span start event with the supplied label list to the exporter.
+// It also returns a function that will end the span, which should normally be
+// deferred.
+func Start1(ctx context.Context, name string, t1 label.Label) (context.Context, func()) {
+	return ExportPair(ctx,
+		MakeEvent([3]label.Label{
+			keys.Start.Of(name),
+			t1,
+		}, nil),
+		MakeEvent([3]label.Label{
+			keys.End.New(),
+		}, nil))
+}
+
+// Start2 sends a span start event with the supplied label list to the exporter.
+// It also returns a function that will end the span, which should normally be
+// deferred.
+func Start2(ctx context.Context, name string, t1, t2 label.Label) (context.Context, func()) {
+	return ExportPair(ctx,
+		MakeEvent([3]label.Label{
+			keys.Start.Of(name),
+			t1,
+			t2,
+		}, nil),
+		MakeEvent([3]label.Label{
+			keys.End.New(),
+		}, nil))
+}

vendor/golang.org/x/tools/internal/event/doc.go

@@ -0,0 +1,7 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package event provides a set of packages that cover the main
+// concepts of telemetry in an implementation agnostic way.
+package event

vendor/golang.org/x/tools/internal/event/event.go

@@ -0,0 +1,127 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package event
+
+import (
+	"context"
+
+	"golang.org/x/tools/internal/event/core"
+	"golang.org/x/tools/internal/event/keys"
+	"golang.org/x/tools/internal/event/label"
+)
+
+// Exporter is a function that handles events.
+// It may return a modified context and event.
+type Exporter func(context.Context, core.Event, label.Map) context.Context
+
+// SetExporter sets the global exporter function that handles all events.
+// The exporter is called synchronously from the event call site, so it should
+// return quickly so as not to hold up user code.
+func SetExporter(e Exporter) {
+	core.SetExporter(core.Exporter(e))
+}
+
+// Log takes a message and a label list and combines them into a single event
+// before delivering them to the exporter.
+func Log(ctx context.Context, message string, labels ...label.Label) {
+	core.Export(ctx, core.MakeEvent([3]label.Label{
+		keys.Msg.Of(message),
+	}, labels))
+}
+
+// IsLog returns true if the event was built by the Log function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsLog(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.Msg
+}
+
+// Error takes a message and a label list and combines them into a single event
+// before delivering them to the exporter. It captures the error in the
+// delivered event.
+func Error(ctx context.Context, message string, err error, labels ...label.Label) {
+	core.Export(ctx, core.MakeEvent([3]label.Label{
+		keys.Msg.Of(message),
+		keys.Err.Of(err),
+	}, labels))
+}
+
+// IsError returns true if the event was built by the Error function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsError(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.Msg &&
+		ev.Label(1).Key() == keys.Err
+}
+
+// Metric sends a label event to the exporter with the supplied labels.
+func Metric(ctx context.Context, labels ...label.Label) {
+	core.Export(ctx, core.MakeEvent([3]label.Label{
+		keys.Metric.New(),
+	}, labels))
+}
+
+// IsMetric returns true if the event was built by the Metric function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsMetric(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.Metric
+}
+
+// Label sends a label event to the exporter with the supplied labels.
+func Label(ctx context.Context, labels ...label.Label) context.Context {
+	return core.Export(ctx, core.MakeEvent([3]label.Label{
+		keys.Label.New(),
+	}, labels))
+}
+
+// IsLabel returns true if the event was built by the Label function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsLabel(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.Label
+}
+
+// Start sends a span start event with the supplied label list to the exporter.
+// It also returns a function that will end the span, which should normally be
+// deferred.
+func Start(ctx context.Context, name string, labels ...label.Label) (context.Context, func()) {
+	return core.ExportPair(ctx,
+		core.MakeEvent([3]label.Label{
+			keys.Start.Of(name),
+		}, labels),
+		core.MakeEvent([3]label.Label{
+			keys.End.New(),
+		}, nil))
+}
+
+// IsStart returns true if the event was built by the Start function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsStart(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.Start
+}
+
+// IsEnd returns true if the event was built by the End function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsEnd(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.End
+}
+
+// Detach returns a context without an associated span.
+// This allows the creation of spans that are not children of the current span.
+func Detach(ctx context.Context) context.Context {
+	return core.Export(ctx, core.MakeEvent([3]label.Label{
+		keys.Detach.New(),
+	}, nil))
+}
+
+// IsDetach returns true if the event was built by the Detach function.
+// It is intended to be used in exporters to identify the semantics of the
+// event when deciding what to do with it.
+func IsDetach(ev core.Event) bool {
+	return ev.Label(0).Key() == keys.Detach
+}

vendor/golang.org/x/tools/internal/event/keys/keys.go

@@ -0,0 +1,564 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package keys
+
+import (
+	"fmt"
+	"io"
+	"math"
+	"strconv"
+
+	"golang.org/x/tools/internal/event/label"
+)
+
+// Value represents a key for untyped values.
+type Value struct {
+	name        string
+	description string
+}
+
+// New creates a new Key for untyped values.
+func New(name, description string) *Value {
+	return &Value{name: name, description: description}
+}
+
+func (k *Value) Name() string        { return k.name }
+func (k *Value) Description() string { return k.description }
+
+func (k *Value) Format(w io.Writer, buf []byte, l label.Label) {
+	fmt.Fprint(w, k.From(l))
+}
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Value) Get(lm label.Map) interface{} {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return nil
+}
+
+// From can be used to get a value from a Label.
+func (k *Value) From(t label.Label) interface{} { return t.UnpackValue() }
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Value) Of(value interface{}) label.Label { return label.OfValue(k, value) }
+
+// Tag represents a key for tagging labels that have no value.
+// These are used when the existence of the label is the entire information it
+// carries, such as marking events to be of a specific kind, or from a specific
+// package.
+type Tag struct {
+	name        string
+	description string
+}
+
+// NewTag creates a new Key for tagging labels.
+func NewTag(name, description string) *Tag {
+	return &Tag{name: name, description: description}
+}
+
+func (k *Tag) Name() string        { return k.name }
+func (k *Tag) Description() string { return k.description }
+
+func (k *Tag) Format(w io.Writer, buf []byte, l label.Label) {}
+
+// New creates a new Label with this key.
+func (k *Tag) New() label.Label { return label.OfValue(k, nil) }
+
+// Int represents a key
+type Int struct {
+	name        string
+	description string
+}
+
+// NewInt creates a new Key for int values.
+func NewInt(name, description string) *Int {
+	return &Int{name: name, description: description}
+}
+
+func (k *Int) Name() string        { return k.name }
+func (k *Int) Description() string { return k.description }
+
+func (k *Int) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendInt(buf, int64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Int) Of(v int) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Int) Get(lm label.Map) int {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Int) From(t label.Label) int { return int(t.Unpack64()) }
+
+// Int8 represents a key
+type Int8 struct {
+	name        string
+	description string
+}
+
+// NewInt8 creates a new Key for int8 values.
+func NewInt8(name, description string) *Int8 {
+	return &Int8{name: name, description: description}
+}
+
+func (k *Int8) Name() string        { return k.name }
+func (k *Int8) Description() string { return k.description }
+
+func (k *Int8) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendInt(buf, int64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Int8) Of(v int8) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Int8) Get(lm label.Map) int8 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Int8) From(t label.Label) int8 { return int8(t.Unpack64()) }
+
+// Int16 represents a key
+type Int16 struct {
+	name        string
+	description string
+}
+
+// NewInt16 creates a new Key for int16 values.
+func NewInt16(name, description string) *Int16 {
+	return &Int16{name: name, description: description}
+}
+
+func (k *Int16) Name() string        { return k.name }
+func (k *Int16) Description() string { return k.description }
+
+func (k *Int16) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendInt(buf, int64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Int16) Of(v int16) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Int16) Get(lm label.Map) int16 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Int16) From(t label.Label) int16 { return int16(t.Unpack64()) }
+
+// Int32 represents a key
+type Int32 struct {
+	name        string
+	description string
+}
+
+// NewInt32 creates a new Key for int32 values.
+func NewInt32(name, description string) *Int32 {
+	return &Int32{name: name, description: description}
+}
+
+func (k *Int32) Name() string        { return k.name }
+func (k *Int32) Description() string { return k.description }
+
+func (k *Int32) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendInt(buf, int64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Int32) Of(v int32) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Int32) Get(lm label.Map) int32 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Int32) From(t label.Label) int32 { return int32(t.Unpack64()) }
+
+// Int64 represents a key
+type Int64 struct {
+	name        string
+	description string
+}
+
+// NewInt64 creates a new Key for int64 values.
+func NewInt64(name, description string) *Int64 {
+	return &Int64{name: name, description: description}
+}
+
+func (k *Int64) Name() string        { return k.name }
+func (k *Int64) Description() string { return k.description }
+
+func (k *Int64) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendInt(buf, k.From(l), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Int64) Of(v int64) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Int64) Get(lm label.Map) int64 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Int64) From(t label.Label) int64 { return int64(t.Unpack64()) }
+
+// UInt represents a key
+type UInt struct {
+	name        string
+	description string
+}
+
+// NewUInt creates a new Key for uint values.
+func NewUInt(name, description string) *UInt {
+	return &UInt{name: name, description: description}
+}
+
+func (k *UInt) Name() string        { return k.name }
+func (k *UInt) Description() string { return k.description }
+
+func (k *UInt) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendUint(buf, uint64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *UInt) Of(v uint) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *UInt) Get(lm label.Map) uint {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *UInt) From(t label.Label) uint { return uint(t.Unpack64()) }
+
+// UInt8 represents a key
+type UInt8 struct {
+	name        string
+	description string
+}
+
+// NewUInt8 creates a new Key for uint8 values.
+func NewUInt8(name, description string) *UInt8 {
+	return &UInt8{name: name, description: description}
+}
+
+func (k *UInt8) Name() string        { return k.name }
+func (k *UInt8) Description() string { return k.description }
+
+func (k *UInt8) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendUint(buf, uint64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *UInt8) Of(v uint8) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *UInt8) Get(lm label.Map) uint8 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *UInt8) From(t label.Label) uint8 { return uint8(t.Unpack64()) }
+
+// UInt16 represents a key
+type UInt16 struct {
+	name        string
+	description string
+}
+
+// NewUInt16 creates a new Key for uint16 values.
+func NewUInt16(name, description string) *UInt16 {
+	return &UInt16{name: name, description: description}
+}
+
+func (k *UInt16) Name() string        { return k.name }
+func (k *UInt16) Description() string { return k.description }
+
+func (k *UInt16) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendUint(buf, uint64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *UInt16) Of(v uint16) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *UInt16) Get(lm label.Map) uint16 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *UInt16) From(t label.Label) uint16 { return uint16(t.Unpack64()) }
+
+// UInt32 represents a key
+type UInt32 struct {
+	name        string
+	description string
+}
+
+// NewUInt32 creates a new Key for uint32 values.
+func NewUInt32(name, description string) *UInt32 {
+	return &UInt32{name: name, description: description}
+}
+
+func (k *UInt32) Name() string        { return k.name }
+func (k *UInt32) Description() string { return k.description }
+
+func (k *UInt32) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendUint(buf, uint64(k.From(l)), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *UInt32) Of(v uint32) label.Label { return label.Of64(k, uint64(v)) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *UInt32) Get(lm label.Map) uint32 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *UInt32) From(t label.Label) uint32 { return uint32(t.Unpack64()) }
+
+// UInt64 represents a key
+type UInt64 struct {
+	name        string
+	description string
+}
+
+// NewUInt64 creates a new Key for uint64 values.
+func NewUInt64(name, description string) *UInt64 {
+	return &UInt64{name: name, description: description}
+}
+
+func (k *UInt64) Name() string        { return k.name }
+func (k *UInt64) Description() string { return k.description }
+
+func (k *UInt64) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendUint(buf, k.From(l), 10))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *UInt64) Of(v uint64) label.Label { return label.Of64(k, v) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *UInt64) Get(lm label.Map) uint64 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *UInt64) From(t label.Label) uint64 { return t.Unpack64() }
+
+// Float32 represents a key
+type Float32 struct {
+	name        string
+	description string
+}
+
+// NewFloat32 creates a new Key for float32 values.
+func NewFloat32(name, description string) *Float32 {
+	return &Float32{name: name, description: description}
+}
+
+func (k *Float32) Name() string        { return k.name }
+func (k *Float32) Description() string { return k.description }
+
+func (k *Float32) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendFloat(buf, float64(k.From(l)), 'E', -1, 32))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Float32) Of(v float32) label.Label {
+	return label.Of64(k, uint64(math.Float32bits(v)))
+}
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Float32) Get(lm label.Map) float32 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Float32) From(t label.Label) float32 {
+	return math.Float32frombits(uint32(t.Unpack64()))
+}
+
+// Float64 represents a key
+type Float64 struct {
+	name        string
+	description string
+}
+
+// NewFloat64 creates a new Key for int64 values.
+func NewFloat64(name, description string) *Float64 {
+	return &Float64{name: name, description: description}
+}
+
+func (k *Float64) Name() string        { return k.name }
+func (k *Float64) Description() string { return k.description }
+
+func (k *Float64) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendFloat(buf, k.From(l), 'E', -1, 64))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Float64) Of(v float64) label.Label {
+	return label.Of64(k, math.Float64bits(v))
+}
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Float64) Get(lm label.Map) float64 {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return 0
+}
+
+// From can be used to get a value from a Label.
+func (k *Float64) From(t label.Label) float64 {
+	return math.Float64frombits(t.Unpack64())
+}
+
+// String represents a key
+type String struct {
+	name        string
+	description string
+}
+
+// NewString creates a new Key for int64 values.
+func NewString(name, description string) *String {
+	return &String{name: name, description: description}
+}
+
+func (k *String) Name() string        { return k.name }
+func (k *String) Description() string { return k.description }
+
+func (k *String) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendQuote(buf, k.From(l)))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *String) Of(v string) label.Label { return label.OfString(k, v) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *String) Get(lm label.Map) string {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return ""
+}
+
+// From can be used to get a value from a Label.
+func (k *String) From(t label.Label) string { return t.UnpackString() }
+
+// Boolean represents a key
+type Boolean struct {
+	name        string
+	description string
+}
+
+// NewBoolean creates a new Key for bool values.
+func NewBoolean(name, description string) *Boolean {
+	return &Boolean{name: name, description: description}
+}
+
+func (k *Boolean) Name() string        { return k.name }
+func (k *Boolean) Description() string { return k.description }
+
+func (k *Boolean) Format(w io.Writer, buf []byte, l label.Label) {
+	w.Write(strconv.AppendBool(buf, k.From(l)))
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Boolean) Of(v bool) label.Label {
+	if v {
+		return label.Of64(k, 1)
+	}
+	return label.Of64(k, 0)
+}
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Boolean) Get(lm label.Map) bool {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return false
+}
+
+// From can be used to get a value from a Label.
+func (k *Boolean) From(t label.Label) bool { return t.Unpack64() > 0 }
+
+// Error represents a key
+type Error struct {
+	name        string
+	description string
+}
+
+// NewError creates a new Key for int64 values.
+func NewError(name, description string) *Error {
+	return &Error{name: name, description: description}
+}
+
+func (k *Error) Name() string        { return k.name }
+func (k *Error) Description() string { return k.description }
+
+func (k *Error) Format(w io.Writer, buf []byte, l label.Label) {
+	io.WriteString(w, k.From(l).Error())
+}
+
+// Of creates a new Label with this key and the supplied value.
+func (k *Error) Of(v error) label.Label { return label.OfValue(k, v) }
+
+// Get can be used to get a label for the key from a label.Map.
+func (k *Error) Get(lm label.Map) error {
+	if t := lm.Find(k); t.Valid() {
+		return k.From(t)
+	}
+	return nil
+}
+
+// From can be used to get a value from a Label.
+func (k *Error) From(t label.Label) error {
+	err, _ := t.UnpackValue().(error)
+	return err
+}

vendor/golang.org/x/tools/internal/event/keys/standard.go

@@ -0,0 +1,22 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package keys
+
+var (
+	// Msg is a key used to add message strings to label lists.
+	Msg = NewString("message", "a readable message")
+	// Label is a key used to indicate an event adds labels to the context.
+	Label = NewTag("label", "a label context marker")
+	// Start is used for things like traces that have a name.
+	Start = NewString("start", "span start")
+	// Metric is a key used to indicate an event records metrics.
+	End = NewTag("end", "a span end marker")
+	// Metric is a key used to indicate an event records metrics.
+	Detach = NewTag("detach", "a span detach marker")
+	// Err is a key used to add error values to label lists.
+	Err = NewError("error", "an error that occurred")
+	// Metric is a key used to indicate an event records metrics.
+	Metric = NewTag("metric", "a metric event marker")
+)

vendor/golang.org/x/tools/internal/event/label/label.go

@@ -0,0 +1,213 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package label
+
+import (
+	"fmt"
+	"io"
+	"reflect"
+	"unsafe"
+)
+
+// Key is used as the identity of a Label.
+// Keys are intended to be compared by pointer only, the name should be unique
+// for communicating with external systems, but it is not required or enforced.
+type Key interface {
+	// Name returns the key name.
+	Name() string
+	// Description returns a string that can be used to describe the value.
+	Description() string
+
+	// Format is used in formatting to append the value of the label to the
+	// supplied buffer.
+	// The formatter may use the supplied buf as a scratch area to avoid
+	// allocations.
+	Format(w io.Writer, buf []byte, l Label)
+}
+
+// Label holds a key and value pair.
+// It is normally used when passing around lists of labels.
+type Label struct {
+	key     Key
+	packed  uint64
+	untyped interface{}
+}
+
+// Map is the interface to a collection of Labels indexed by key.
+type Map interface {
+	// Find returns the label that matches the supplied key.
+	Find(key Key) Label
+}
+
+// List is the interface to something that provides an iterable
+// list of labels.
+// Iteration should start from 0 and continue until Valid returns false.
+type List interface {
+	// Valid returns true if the index is within range for the list.
+	// It does not imply the label at that index will itself be valid.
+	Valid(index int) bool
+	// Label returns the label at the given index.
+	Label(index int) Label
+}
+
+// list implements LabelList for a list of Labels.
+type list struct {
+	labels []Label
+}
+
+// filter wraps a LabelList filtering out specific labels.
+type filter struct {
+	keys       []Key
+	underlying List
+}
+
+// listMap implements LabelMap for a simple list of labels.
+type listMap struct {
+	labels []Label
+}
+
+// mapChain implements LabelMap for a list of underlying LabelMap.
+type mapChain struct {
+	maps []Map
+}
+
+// OfValue creates a new label from the key and value.
+// This method is for implementing new key types, label creation should
+// normally be done with the Of method of the key.
+func OfValue(k Key, value interface{}) Label { return Label{key: k, untyped: value} }
+
+// UnpackValue assumes the label was built using LabelOfValue and returns the value
+// that was passed to that constructor.
+// This method is for implementing new key types, for type safety normal
+// access should be done with the From method of the key.
+func (t Label) UnpackValue() interface{} { return t.untyped }
+
+// Of64 creates a new label from a key and a uint64. This is often
+// used for non uint64 values that can be packed into a uint64.
+// This method is for implementing new key types, label creation should
+// normally be done with the Of method of the key.
+func Of64(k Key, v uint64) Label { return Label{key: k, packed: v} }
+
+// Unpack64 assumes the label was built using LabelOf64 and returns the value that
+// was passed to that constructor.
+// This method is for implementing new key types, for type safety normal
+// access should be done with the From method of the key.
+func (t Label) Unpack64() uint64 { return t.packed }
+
+// OfString creates a new label from a key and a string.
+// This method is for implementing new key types, label creation should
+// normally be done with the Of method of the key.
+func OfString(k Key, v string) Label {
+	hdr := (*reflect.StringHeader)(unsafe.Pointer(&v))
+	return Label{
+		key:     k,
+		packed:  uint64(hdr.Len),
+		untyped: unsafe.Pointer(hdr.Data),
+	}
+}
+
+// UnpackString assumes the label was built using LabelOfString and returns the
+// value that was passed to that constructor.
+// This method is for implementing new key types, for type safety normal
+// access should be done with the From method of the key.
+func (t Label) UnpackString() string {
+	var v string
+	hdr := (*reflect.StringHeader)(unsafe.Pointer(&v))
+	hdr.Data = uintptr(t.untyped.(unsafe.Pointer))
+	hdr.Len = int(t.packed)
+	return *(*string)(unsafe.Pointer(hdr))
+}
+
+// Valid returns true if the Label is a valid one (it has a key).
+func (t Label) Valid() bool { return t.key != nil }
+
+// Key returns the key of this Label.
+func (t Label) Key() Key { return t.key }
+
+// Format is used for debug printing of labels.
+func (t Label) Format(f fmt.State, r rune) {
+	if !t.Valid() {
+		io.WriteString(f, `nil`)
+		return
+	}
+	io.WriteString(f, t.Key().Name())
+	io.WriteString(f, "=")
+	var buf [128]byte
+	t.Key().Format(f, buf[:0], t)
+}
+
+func (l *list) Valid(index int) bool {
+	return index >= 0 && index < len(l.labels)
+}
+
+func (l *list) Label(index int) Label {
+	return l.labels[index]
+}
+
+func (f *filter) Valid(index int) bool {
+	return f.underlying.Valid(index)
+}
+
+func (f *filter) Label(index int) Label {
+	l := f.underlying.Label(index)
+	for _, f := range f.keys {
+		if l.Key() == f {
+			return Label{}
+		}
+	}
+	return l
+}
+
+func (lm listMap) Find(key Key) Label {
+	for _, l := range lm.labels {
+		if l.Key() == key {
+			return l
+		}
+	}
+	return Label{}
+}
+
+func (c mapChain) Find(key Key) Label {
+	for _, src := range c.maps {
+		l := src.Find(key)
+		if l.Valid() {
+			return l
+		}
+	}
+	return Label{}
+}
+
+var emptyList = &list{}
+
+func NewList(labels ...Label) List {
+	if len(labels) == 0 {
+		return emptyList
+	}
+	return &list{labels: labels}
+}
+
+func Filter(l List, keys ...Key) List {
+	if len(keys) == 0 {
+		return l
+	}
+	return &filter{keys: keys, underlying: l}
+}
+
+func NewMap(labels ...Label) Map {
+	return listMap{labels: labels}
+}
+
+func MergeMaps(srcs ...Map) Map {
+	var nonNil []Map
+	for _, src := range srcs {
+		if src != nil {
+			nonNil = append(nonNil, src)
+		}
+	}
+	if len(nonNil) == 1 {
+		return nonNil[0]
+	}
+	return mapChain{maps: nonNil}
+}

vendor/golang.org/x/tools/internal/gocommand/invoke.go

@@ -1,3 +1,7 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
 // Package gocommand is a helper for calling the go command.
 package gocommand
 
@@ -8,10 +12,119 @@ import (
 	"io"
 	"os"
 	"os/exec"
+	"regexp"
 	"strings"
+	"sync"
 	"time"
+
+	"golang.org/x/tools/internal/event"
 )
 
+// An Runner will run go command invocations and serialize
+// them if it sees a concurrency error.
+type Runner struct {
+	// once guards the runner initialization.
+	once sync.Once
+
+	// inFlight tracks available workers.
+	inFlight chan struct{}
+
+	// serialized guards the ability to run a go command serially,
+	// to avoid deadlocks when claiming workers.
+	serialized chan struct{}
+}
+
+const maxInFlight = 10
+
+func (runner *Runner) initialize() {
+	runner.once.Do(func() {
+		runner.inFlight = make(chan struct{}, maxInFlight)
+		runner.serialized = make(chan struct{}, 1)
+	})
+}
+
+// 1.13: go: updates to go.mod needed, but contents have changed
+// 1.14: go: updating go.mod: existing contents have changed since last read
+var modConcurrencyError = regexp.MustCompile(`go:.*go.mod.*contents have changed`)
+
+// Run is a convenience wrapper around RunRaw.
+// It returns only stdout and a "friendly" error.
+func (runner *Runner) Run(ctx context.Context, inv Invocation) (*bytes.Buffer, error) {
+	stdout, _, friendly, _ := runner.RunRaw(ctx, inv)
+	return stdout, friendly
+}
+
+// RunPiped runs the invocation serially, always waiting for any concurrent
+// invocations to complete first.
+func (runner *Runner) RunPiped(ctx context.Context, inv Invocation, stdout, stderr io.Writer) error {
+	_, err := runner.runPiped(ctx, inv, stdout, stderr)
+	return err
+}
+
+// RunRaw runs the invocation, serializing requests only if they fight over
+// go.mod changes.
+func (runner *Runner) RunRaw(ctx context.Context, inv Invocation) (*bytes.Buffer, *bytes.Buffer, error, error) {
+	// Make sure the runner is always initialized.
+	runner.initialize()
+
+	// First, try to run the go command concurrently.
+	stdout, stderr, friendlyErr, err := runner.runConcurrent(ctx, inv)
+
+	// If we encounter a load concurrency error, we need to retry serially.
+	if friendlyErr == nil || !modConcurrencyError.MatchString(friendlyErr.Error()) {
+		return stdout, stderr, friendlyErr, err
+	}
+	event.Error(ctx, "Load concurrency error, will retry serially", err)
+
+	// Run serially by calling runPiped.
+	stdout.Reset()
+	stderr.Reset()
+	friendlyErr, err = runner.runPiped(ctx, inv, stdout, stderr)
+	return stdout, stderr, friendlyErr, err
+}
+
+func (runner *Runner) runConcurrent(ctx context.Context, inv Invocation) (*bytes.Buffer, *bytes.Buffer, error, error) {
+	// Wait for 1 worker to become available.
+	select {
+	case <-ctx.Done():
+		return nil, nil, nil, ctx.Err()
+	case runner.inFlight <- struct{}{}:
+		defer func() { <-runner.inFlight }()
+	}
+
+	stdout, stderr := &bytes.Buffer{}, &bytes.Buffer{}
+	friendlyErr, err := inv.runWithFriendlyError(ctx, stdout, stderr)
+	return stdout, stderr, friendlyErr, err
+}
+
+func (runner *Runner) runPiped(ctx context.Context, inv Invocation, stdout, stderr io.Writer) (error, error) {
+	// Make sure the runner is always initialized.
+	runner.initialize()
+
+	// Acquire the serialization lock. This avoids deadlocks between two
+	// runPiped commands.
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	case runner.serialized <- struct{}{}:
+		defer func() { <-runner.serialized }()
+	}
+
+	// Wait for all in-progress go commands to return before proceeding,
+	// to avoid load concurrency errors.
+	for i := 0; i < maxInFlight; i++ {
+		select {
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		case runner.inFlight <- struct{}{}:
+			// Make sure we always "return" any workers we took.
+			defer func() { <-runner.inFlight }()
+		}
+	}
+
+	return inv.runWithFriendlyError(ctx, stdout, stderr)
+}
+
 // An Invocation represents a call to the go command.
 type Invocation struct {
 	Verb       string
@@ -22,20 +135,10 @@ type Invocation struct {
 	Logf       func(format string, args ...interface{})
 }
 
-// Run runs the invocation, returning its stdout and an error suitable for
-// human consumption, including stderr.
-func (i *Invocation) Run(ctx context.Context) (*bytes.Buffer, error) {
-	stdout, _, friendly, _ := i.RunRaw(ctx)
-	return stdout, friendly
-}
-
-// RunRaw is like RunPiped, but also returns the raw stderr and error for callers
-// that want to do low-level error handling/recovery.
-func (i *Invocation) RunRaw(ctx context.Context) (stdout *bytes.Buffer, stderr *bytes.Buffer, friendlyError error, rawError error) {
-	stdout = &bytes.Buffer{}
-	stderr = &bytes.Buffer{}
-	rawError = i.RunPiped(ctx, stdout, stderr)
+func (i *Invocation) runWithFriendlyError(ctx context.Context, stdout, stderr io.Writer) (friendlyError error, rawError error) {
+	rawError = i.run(ctx, stdout, stderr)
 	if rawError != nil {
+		friendlyError = rawError
 		// Check for 'go' executable not being found.
 		if ee, ok := rawError.(*exec.Error); ok && ee.Err == exec.ErrNotFound {
 			friendlyError = fmt.Errorf("go command required, not found: %v", ee)
@@ -43,13 +146,12 @@ func (i *Invocation) RunRaw(ctx context.Context) (stdout *bytes.Buffer, stderr *
 		if ctx.Err() != nil {
 			friendlyError = ctx.Err()
 		}
-		friendlyError = fmt.Errorf("err: %v: stderr: %s", rawError, stderr)
+		friendlyError = fmt.Errorf("err: %v: stderr: %s", friendlyError, stderr)
 	}
 	return
 }
 
-// RunPiped is like Run, but relies on the given stdout/stderr
-func (i *Invocation) RunPiped(ctx context.Context, stdout, stderr io.Writer) error {
+func (i *Invocation) run(ctx context.Context, stdout, stderr io.Writer) error {
 	log := i.Logf
 	if log == nil {
 		log = func(string, ...interface{}) {}
@@ -78,9 +180,11 @@ func (i *Invocation) RunPiped(ctx context.Context, stdout, stderr io.Writer) err
 	// The Go stdlib has a special feature where if the cwd and the PWD are the
 	// same node then it trusts the PWD, so by setting it in the env for the child
 	// process we fix up all the paths returned by the go command.
-	cmd.Env = append(append([]string{}, i.Env...), "PWD="+i.WorkingDir)
-	cmd.Dir = i.WorkingDir
-
+	cmd.Env = append(os.Environ(), i.Env...)
+	if i.WorkingDir != "" {
+		cmd.Env = append(cmd.Env, "PWD="+i.WorkingDir)
+		cmd.Dir = i.WorkingDir
+	}
 	defer func(start time.Time) { log("%s for %v", time.Since(start), cmdDebugStr(cmd)) }(time.Now())
 
 	return runCmdContext(ctx, cmd)

vendor/golang.org/x/tools/internal/gocommand/vendor.go

@@ -0,0 +1,102 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gocommand
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"golang.org/x/mod/semver"
+)
+
+// ModuleJSON holds information about a module.
+type ModuleJSON struct {
+	Path      string      // module path
+	Replace   *ModuleJSON // replaced by this module
+	Main      bool        // is this the main module?
+	Indirect  bool        // is this module only an indirect dependency of main module?
+	Dir       string      // directory holding files for this module, if any
+	GoMod     string      // path to go.mod file for this module, if any
+	GoVersion string      // go version used in module
+}
+
+var modFlagRegexp = regexp.MustCompile(`-mod[ =](\w+)`)
+
+// VendorEnabled reports whether vendoring is enabled. It takes a *Runner to execute Go commands
+// with the supplied context.Context and Invocation. The Invocation can contain pre-defined fields,
+// of which only Verb and Args are modified to run the appropriate Go command.
+// Inspired by setDefaultBuildMod in modload/init.go
+func VendorEnabled(ctx context.Context, inv Invocation, r *Runner) (*ModuleJSON, bool, error) {
+	mainMod, go114, err := getMainModuleAnd114(ctx, inv, r)
+	if err != nil {
+		return nil, false, err
+	}
+
+	// We check the GOFLAGS to see if there is anything overridden or not.
+	inv.Verb = "env"
+	inv.Args = []string{"GOFLAGS"}
+	stdout, err := r.Run(ctx, inv)
+	if err != nil {
+		return nil, false, err
+	}
+	goflags := string(bytes.TrimSpace(stdout.Bytes()))
+	matches := modFlagRegexp.FindStringSubmatch(goflags)
+	var modFlag string
+	if len(matches) != 0 {
+		modFlag = matches[1]
+	}
+	if modFlag != "" {
+		// Don't override an explicit '-mod=' argument.
+		return mainMod, modFlag == "vendor", nil
+	}
+	if mainMod == nil || !go114 {
+		return mainMod, false, nil
+	}
+	// Check 1.14's automatic vendor mode.
+	if fi, err := os.Stat(filepath.Join(mainMod.Dir, "vendor")); err == nil && fi.IsDir() {
+		if mainMod.GoVersion != "" && semver.Compare("v"+mainMod.GoVersion, "v1.14") >= 0 {
+			// The Go version is at least 1.14, and a vendor directory exists.
+			// Set -mod=vendor by default.
+			return mainMod, true, nil
+		}
+	}
+	return mainMod, false, nil
+}
+
+// getMainModuleAnd114 gets the main module's information and whether the
+// go command in use is 1.14+. This is the information needed to figure out
+// if vendoring should be enabled.
+func getMainModuleAnd114(ctx context.Context, inv Invocation, r *Runner) (*ModuleJSON, bool, error) {
+	const format = `{{.Path}}
+{{.Dir}}
+{{.GoMod}}
+{{.GoVersion}}
+{{range context.ReleaseTags}}{{if eq . "go1.14"}}{{.}}{{end}}{{end}}
+`
+	inv.Verb = "list"
+	inv.Args = []string{"-m", "-f", format}
+	stdout, err := r.Run(ctx, inv)
+	if err != nil {
+		return nil, false, err
+	}
+
+	lines := strings.Split(stdout.String(), "\n")
+	if len(lines) < 5 {
+		return nil, false, fmt.Errorf("unexpected stdout: %q", stdout.String())
+	}
+	mod := &ModuleJSON{
+		Path:      lines[0],
+		Dir:       lines[1],
+		GoMod:     lines[2],
+		GoVersion: lines[3],
+		Main:      true,
+	}
+	return mod, lines[4] == "go1.14", nil
+}

vendor/golang.org/x/tools/internal/gopathwalk/walk.go

@@ -10,7 +10,6 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
-	"go/build"
 	"io/ioutil"
 	"log"
 	"os"
@@ -47,16 +46,6 @@ type Root struct {
 	Type RootType
 }
 
-// SrcDirsRoots returns the roots from build.Default.SrcDirs(). Not modules-compatible.
-func SrcDirsRoots(ctx *build.Context) []Root {
-	var roots []Root
-	roots = append(roots, Root{filepath.Join(ctx.GOROOT, "src"), RootGOROOT})
-	for _, p := range filepath.SplitList(ctx.GOPATH) {
-		roots = append(roots, Root{filepath.Join(p, "src"), RootGOPATH})
-	}
-	return roots
-}
-
 // Walk walks Go source directories ($GOROOT, $GOPATH, etc) to find packages.
 // For each package found, add will be called (concurrently) with the absolute
 // paths of the containing source directory and the package directory.

vendor/golang.org/x/tools/internal/imports/fix.go

@@ -7,6 +7,7 @@ package imports
 import (
 	"bytes"
 	"context"
+	"encoding/json"
 	"fmt"
 	"go/ast"
 	"go/build"
@@ -31,35 +32,36 @@ import (
 
 // importToGroup is a list of functions which map from an import path to
 // a group number.
-var importToGroup = []func(env *ProcessEnv, importPath string) (num int, ok bool){
-	func(env *ProcessEnv, importPath string) (num int, ok bool) {
-		if env.LocalPrefix == "" {
+var importToGroup = []func(localPrefix, importPath string) (num int, ok bool){
+	func(localPrefix, importPath string) (num int, ok bool) {
+		if localPrefix == "" {
 			return
 		}
-		for _, p := range strings.Split(env.LocalPrefix, ",") {
+		for _, p := range strings.Split(localPrefix, ",") {
 			if strings.HasPrefix(importPath, p) || strings.TrimSuffix(p, "/") == importPath {
 				return 3, true
 			}
 		}
 		return
 	},
-	func(_ *ProcessEnv, importPath string) (num int, ok bool) {
+	func(_, importPath string) (num int, ok bool) {
 		if strings.HasPrefix(importPath, "appengine") {
 			return 2, true
 		}
 		return
 	},
-	func(_ *ProcessEnv, importPath string) (num int, ok bool) {
-		if strings.Contains(importPath, ".") {
+	func(_, importPath string) (num int, ok bool) {
+		firstComponent := strings.Split(importPath, "/")[0]
+		if strings.Contains(firstComponent, ".") {
 			return 1, true
 		}
 		return
 	},
 }
 
-func importGroup(env *ProcessEnv, importPath string) int {
+func importGroup(localPrefix, importPath string) int {
 	for _, fn := range importToGroup {
-		if n, ok := fn(env, importPath); ok {
+		if n, ok := fn(localPrefix, importPath); ok {
 			return n
 		}
 	}
@@ -276,7 +278,12 @@ func (p *pass) loadPackageNames(imports []*ImportInfo) error {
 		unknown = append(unknown, imp.ImportPath)
 	}
 
-	names, err := p.env.GetResolver().loadPackageNames(unknown, p.srcDir)
+	resolver, err := p.env.GetResolver()
+	if err != nil {
+		return err
+	}
+
+	names, err := resolver.loadPackageNames(unknown, p.srcDir)
 	if err != nil {
 		return err
 	}
@@ -566,7 +573,9 @@ func getFixes(fset *token.FileSet, f *ast.File, filename string, env *ProcessEnv
 		return fixes, nil
 	}
 
-	addStdlibCandidates(p, p.missingRefs)
+	if err := addStdlibCandidates(p, p.missingRefs); err != nil {
+		return nil, err
+	}
 	p.assumeSiblingImportsValid()
 	if fixes, done := p.fix(); done {
 		return fixes, nil
@@ -594,10 +603,14 @@ func getCandidatePkgs(ctx context.Context, wrappedCallback *scanCallback, filena
 	notSelf := func(p *pkg) bool {
 		return p.packageName != filePkg || p.dir != filepath.Dir(filename)
 	}
+	goenv, err := env.goEnv()
+	if err != nil {
+		return err
+	}
 	// Start off with the standard library.
 	for importPath, exports := range stdlib {
 		p := &pkg{
-			dir:             filepath.Join(env.GOROOT, "src", importPath),
+			dir:             filepath.Join(goenv["GOROOT"], "src", importPath),
 			importPathShort: importPath,
 			packageName:     path.Base(importPath),
 			relevance:       MaxRelevance,
@@ -638,15 +651,23 @@ func getCandidatePkgs(ctx context.Context, wrappedCallback *scanCallback, filena
 			wrappedCallback.exportsLoaded(pkg, exports)
 		},
 	}
-	return env.GetResolver().scan(ctx, scanFilter)
+	resolver, err := env.GetResolver()
+	if err != nil {
+		return err
+	}
+	return resolver.scan(ctx, scanFilter)
 }
 
-func ScoreImportPaths(ctx context.Context, env *ProcessEnv, paths []string) map[string]int {
+func ScoreImportPaths(ctx context.Context, env *ProcessEnv, paths []string) (map[string]int, error) {
 	result := make(map[string]int)
-	for _, path := range paths {
-		result[path] = env.GetResolver().scoreImportPath(ctx, path)
+	resolver, err := env.GetResolver()
+	if err != nil {
+		return nil, err
 	}
-	return result
+	for _, path := range paths {
+		result[path] = resolver.scoreImportPath(ctx, path)
+	}
+	return result, nil
 }
 
 func PrimeCache(ctx context.Context, env *ProcessEnv) error {
@@ -672,8 +693,9 @@ func candidateImportName(pkg *pkg) string {
 	return ""
 }
 
-// getAllCandidates gets all of the candidates to be imported, regardless of if they are needed.
-func getAllCandidates(ctx context.Context, wrapped func(ImportFix), searchPrefix, filename, filePkg string, env *ProcessEnv) error {
+// GetAllCandidates gets all of the packages starting with prefix that can be
+// imported by filename, sorted by import path.
+func GetAllCandidates(ctx context.Context, wrapped func(ImportFix), searchPrefix, filename, filePkg string, env *ProcessEnv) error {
 	callback := &scanCallback{
 		rootFound: func(gopathwalk.Root) bool {
 			return true
@@ -712,7 +734,8 @@ type PackageExport struct {
 	Exports []string
 }
 
-func getPackageExports(ctx context.Context, wrapped func(PackageExport), searchPkg, filename, filePkg string, env *ProcessEnv) error {
+// GetPackageExports returns all known packages with name pkg and their exports.
+func GetPackageExports(ctx context.Context, wrapped func(PackageExport), searchPkg, filename, filePkg string, env *ProcessEnv) error {
 	callback := &scanCallback{
 		rootFound: func(gopathwalk.Root) bool {
 			return true
@@ -742,67 +765,126 @@ func getPackageExports(ctx context.Context, wrapped func(PackageExport), searchP
 	return getCandidatePkgs(ctx, callback, filename, filePkg, env)
 }
 
+var RequiredGoEnvVars = []string{"GO111MODULE", "GOFLAGS", "GOINSECURE", "GOMOD", "GOMODCACHE", "GONOPROXY", "GONOSUMDB", "GOPATH", "GOPROXY", "GOROOT", "GOSUMDB"}
+
 // ProcessEnv contains environment variables and settings that affect the use of
 // the go command, the go/build package, etc.
 type ProcessEnv struct {
-	LocalPrefix string
+	GocmdRunner *gocommand.Runner
 
 	BuildFlags []string
 
-	// If non-empty, these will be used instead of the
-	// process-wide values.
-	GOPATH, GOROOT, GO111MODULE, GOPROXY, GOFLAGS, GOSUMDB string
-	WorkingDir                                             string
+	// Env overrides the OS environment, and can be used to specify
+	// GOPROXY, GO111MODULE, etc. PATH cannot be set here, because
+	// exec.Command will not honor it.
+	// Specifying all of RequiredGoEnvVars avoids a call to `go env`.
+	Env map[string]string
+
+	WorkingDir string
 
 	// If Logf is non-nil, debug logging is enabled through this function.
 	Logf func(format string, args ...interface{})
 
+	initialized bool
+
 	resolver Resolver
 }
 
+func (e *ProcessEnv) goEnv() (map[string]string, error) {
+	if err := e.init(); err != nil {
+		return nil, err
+	}
+	return e.Env, nil
+}
+
+func (e *ProcessEnv) matchFile(dir, name string) (bool, error) {
+	return build.Default.MatchFile(dir, name)
+}
+
 // CopyConfig copies the env's configuration into a new env.
 func (e *ProcessEnv) CopyConfig() *ProcessEnv {
-	copy := *e
-	copy.resolver = nil
-	return &copy
+	copy := &ProcessEnv{
+		GocmdRunner: e.GocmdRunner,
+		initialized: e.initialized,
+		BuildFlags:  e.BuildFlags,
+		Logf:        e.Logf,
+		WorkingDir:  e.WorkingDir,
+		resolver:    nil,
+		Env:         map[string]string{},
+	}
+	for k, v := range e.Env {
+		copy.Env[k] = v
+	}
+	return copy
+}
+
+func (e *ProcessEnv) init() error {
+	if e.initialized {
+		return nil
+	}
+
+	foundAllRequired := true
+	for _, k := range RequiredGoEnvVars {
+		if _, ok := e.Env[k]; !ok {
+			foundAllRequired = false
+			break
+		}
+	}
+	if foundAllRequired {
+		e.initialized = true
+		return nil
+	}
+
+	if e.Env == nil {
+		e.Env = map[string]string{}
+	}
+
+	goEnv := map[string]string{}
+	stdout, err := e.invokeGo(context.TODO(), "env", append([]string{"-json"}, RequiredGoEnvVars...)...)
+	if err != nil {
+		return err
+	}
+	if err := json.Unmarshal(stdout.Bytes(), &goEnv); err != nil {
+		return err
+	}
+	for k, v := range goEnv {
+		e.Env[k] = v
+	}
+	e.initialized = true
+	return nil
 }
 
 func (e *ProcessEnv) env() []string {
-	env := os.Environ()
-	add := func(k, v string) {
-		if v != "" {
-			env = append(env, k+"="+v)
-		}
-	}
-	add("GOPATH", e.GOPATH)
-	add("GOROOT", e.GOROOT)
-	add("GO111MODULE", e.GO111MODULE)
-	add("GOPROXY", e.GOPROXY)
-	add("GOFLAGS", e.GOFLAGS)
-	add("GOSUMDB", e.GOSUMDB)
-	if e.WorkingDir != "" {
-		add("PWD", e.WorkingDir)
+	var env []string // the gocommand package will prepend os.Environ.
+	for k, v := range e.Env {
+		env = append(env, k+"="+v)
 	}
 	return env
 }
 
-func (e *ProcessEnv) GetResolver() Resolver {
+func (e *ProcessEnv) GetResolver() (Resolver, error) {
 	if e.resolver != nil {
-		return e.resolver
+		return e.resolver, nil
 	}
-	out, err := e.invokeGo(context.TODO(), "env", "GOMOD")
-	if err != nil || len(bytes.TrimSpace(out.Bytes())) == 0 {
+	if err := e.init(); err != nil {
+		return nil, err
+	}
+	if len(e.Env["GOMOD"]) == 0 {
 		e.resolver = newGopathResolver(e)
-		return e.resolver
+		return e.resolver, nil
 	}
 	e.resolver = newModuleResolver(e)
-	return e.resolver
+	return e.resolver, nil
 }
 
-func (e *ProcessEnv) buildContext() *build.Context {
+func (e *ProcessEnv) buildContext() (*build.Context, error) {
 	ctx := build.Default
-	ctx.GOROOT = e.GOROOT
-	ctx.GOPATH = e.GOPATH
+	goenv, err := e.goEnv()
+	if err != nil {
+		return nil, err
+	}
+	ctx.GOROOT = goenv["GOROOT"]
+	ctx.GOPATH = goenv["GOPATH"]
 
 	// As of Go 1.14, build.Context has a Dir field
 	// (see golang.org/issue/34860).
@@ -818,7 +900,7 @@ func (e *ProcessEnv) buildContext() *build.Context {
 		dir.SetString(e.WorkingDir)
 	}
 
-	return &ctx
+	return &ctx, nil
 }
 
 func (e *ProcessEnv) invokeGo(ctx context.Context, verb string, args ...string) (*bytes.Buffer, error) {
@@ -830,13 +912,17 @@ func (e *ProcessEnv) invokeGo(ctx context.Context, verb string, args ...string)
 		Logf:       e.Logf,
 		WorkingDir: e.WorkingDir,
 	}
-	return inv.Run(ctx)
+	return e.GocmdRunner.Run(ctx, inv)
 }
 
-func addStdlibCandidates(pass *pass, refs references) {
+func addStdlibCandidates(pass *pass, refs references) error {
+	goenv, err := pass.env.goEnv()
+	if err != nil {
+		return err
+	}
 	add := func(pkg string) {
 		// Prevent self-imports.
-		if path.Base(pkg) == pass.f.Name.Name && filepath.Join(pass.env.GOROOT, "src", pkg) == pass.srcDir {
+		if path.Base(pkg) == pass.f.Name.Name && filepath.Join(goenv["GOROOT"], "src", pkg) == pass.srcDir {
 			return
 		}
 		exports := copyExports(stdlib[pkg])
@@ -857,6 +943,7 @@ func addStdlibCandidates(pass *pass, refs references) {
 			}
 		}
 	}
+	return nil
 }
 
 // A Resolver does the build-system-specific parts of goimports.
@@ -921,10 +1008,13 @@ func addExternalCandidates(pass *pass, refs references, filename string) error {
 			return false // We'll do our own loading after we sort.
 		},
 	}
-	err := pass.env.GetResolver().scan(context.Background(), callback)
+	resolver, err := pass.env.GetResolver()
 	if err != nil {
 		return err
 	}
+	if err = resolver.scan(context.Background(), callback); err != nil {
+		return err
+	}
 
 	// Search for imports matching potential package references.
 	type result struct {
@@ -1050,21 +1140,24 @@ func (r *gopathResolver) ClearForNewScan() {
 
 func (r *gopathResolver) loadPackageNames(importPaths []string, srcDir string) (map[string]string, error) {
 	names := map[string]string{}
+	bctx, err := r.env.buildContext()
+	if err != nil {
+		return nil, err
+	}
 	for _, path := range importPaths {
-		names[path] = importPathToName(r.env, path, srcDir)
+		names[path] = importPathToName(bctx, path, srcDir)
 	}
 	return names, nil
 }
 
 // importPathToName finds out the actual package name, as declared in its .go files.
-// If there's a problem, it returns "".
-func importPathToName(env *ProcessEnv, importPath, srcDir string) (packageName string) {
+func importPathToName(bctx *build.Context, importPath, srcDir string) string {
 	// Fast path for standard library without going to disk.
 	if _, ok := stdlib[importPath]; ok {
 		return path.Base(importPath) // stdlib packages always match their paths.
 	}
 
-	buildPkg, err := env.buildContext().Import(importPath, srcDir, build.FindOnly)
+	buildPkg, err := bctx.Import(importPath, srcDir, build.FindOnly)
 	if err != nil {
 		return ""
 	}
@@ -1225,8 +1318,18 @@ func (r *gopathResolver) scan(ctx context.Context, callback *scanCallback) error
 	}
 	stop := r.cache.ScanAndListen(ctx, processDir)
 	defer stop()
+
+	goenv, err := r.env.goEnv()
+	if err != nil {
+		return err
+	}
+	var roots []gopathwalk.Root
+	roots = append(roots, gopathwalk.Root{filepath.Join(goenv["GOROOT"], "src"), gopathwalk.RootGOROOT})
+	for _, p := range filepath.SplitList(goenv["GOPATH"]) {
+		roots = append(roots, gopathwalk.Root{filepath.Join(p, "src"), gopathwalk.RootGOPATH})
+	}
 	// The callback is not necessarily safe to use in the goroutine below. Process roots eagerly.
-	roots := filterRoots(gopathwalk.SrcDirsRoots(r.env.buildContext()), callback.rootFound)
+	roots = filterRoots(roots, callback.rootFound)
 	// We can't cancel walks, because we need them to finish to have a usable
 	// cache. Instead, run them in a separate goroutine and detach.
 	scanDone := make(chan struct{})
@@ -1286,8 +1389,6 @@ func VendorlessPath(ipath string) string {
 }
 
 func loadExportsFromFiles(ctx context.Context, env *ProcessEnv, dir string, includeTest bool) (string, []string, error) {
-	var exports []string
-
 	// Look for non-test, buildable .go files which could provide exports.
 	all, err := ioutil.ReadDir(dir)
 	if err != nil {
@@ -1299,7 +1400,7 @@ func loadExportsFromFiles(ctx context.Context, env *ProcessEnv, dir string, incl
 		if !strings.HasSuffix(name, ".go") || (!includeTest && strings.HasSuffix(name, "_test.go")) {
 			continue
 		}
-		match, err := env.buildContext().MatchFile(dir, fi.Name())
+		match, err := env.matchFile(dir, fi.Name())
 		if err != nil || !match {
 			continue
 		}
@@ -1311,6 +1412,7 @@ func loadExportsFromFiles(ctx context.Context, env *ProcessEnv, dir string, incl
 	}
 
 	var pkgName string
+	var exports []string
 	fset := token.NewFileSet()
 	for _, fi := range files {
 		select {
@@ -1322,7 +1424,10 @@ func loadExportsFromFiles(ctx context.Context, env *ProcessEnv, dir string, incl
 		fullFile := filepath.Join(dir, fi.Name())
 		f, err := parser.ParseFile(fset, fullFile, nil, 0)
 		if err != nil {
-			return "", nil, fmt.Errorf("parsing %s: %v", fullFile, err)
+			if env.Logf != nil {
+				env.Logf("error parsing %v: %v", fullFile, err)
+			}
+			continue
 		}
 		if f.Name.Name == "documentation" {
 			// Special case from go/build.ImportDir, not
@@ -1362,6 +1467,10 @@ func findImport(ctx context.Context, pass *pass, candidates []pkgDistance, pkgNa
 			pass.env.Logf("%s candidate %d/%d: %v in %v", pkgName, i+1, len(candidates), c.pkg.importPathShort, c.pkg.dir)
 		}
 	}
+	resolver, err := pass.env.GetResolver()
+	if err != nil {
+		return nil, err
+	}
 
 	// Collect exports for packages with matching names.
 	rescv := make([]chan *pkg, len(candidates))
@@ -1400,7 +1509,7 @@ func findImport(ctx context.Context, pass *pass, candidates []pkgDistance, pkgNa
 				}
 				// If we're an x_test, load the package under test's test variant.
 				includeTest := strings.HasSuffix(pass.f.Name.Name, "_test") && c.pkg.dir == pass.srcDir
-				_, exports, err := pass.env.GetResolver().loadExports(ctx, c.pkg, includeTest)
+				_, exports, err := resolver.loadExports(ctx, c.pkg, includeTest)
 				if err != nil {
 					if pass.env.Logf != nil {
 						pass.env.Logf("loading exports in dir %s (seeking package %s): %v", c.pkg.dir, pkgName, err)

vendor/golang.org/x/tools/internal/imports/imports.go

@@ -11,17 +11,13 @@ package imports
 import (
 	"bufio"
 	"bytes"
-	"context"
 	"fmt"
 	"go/ast"
-	"go/build"
 	"go/format"
 	"go/parser"
 	"go/printer"
 	"go/token"
 	"io"
-	"io/ioutil"
-	"os"
 	"regexp"
 	"strconv"
 	"strings"
@@ -33,6 +29,11 @@ import (
 type Options struct {
 	Env *ProcessEnv // The environment to use. Note: this contains the cached module and filesystem state.
 
+	// LocalPrefix is a comma-separated string of import path prefixes, which, if
+	// set, instructs Process to sort the import paths with the given prefixes
+	// into another group after 3rd-party packages.
+	LocalPrefix string
+
 	Fragment  bool // Accept fragment of a source file (no package statement)
 	AllErrors bool // Report all errors (not just the first 10 on different lines)
 
@@ -43,13 +44,8 @@ type Options struct {
 	FormatOnly bool // Disable the insertion and deletion of imports
 }
 
-// Process implements golang.org/x/tools/imports.Process with explicit context in env.
+// Process implements golang.org/x/tools/imports.Process with explicit context in opt.Env.
 func Process(filename string, src []byte, opt *Options) (formatted []byte, err error) {
-	src, opt, err = initialize(filename, src, opt)
-	if err != nil {
-		return nil, err
-	}
-
 	fileSet := token.NewFileSet()
 	file, adjust, err := parse(fileSet, filename, src, opt)
 	if err != nil {
@@ -65,16 +61,12 @@ func Process(filename string, src []byte, opt *Options) (formatted []byte, err e
 }
 
 // FixImports returns a list of fixes to the imports that, when applied,
-// will leave the imports in the same state as Process.
+// will leave the imports in the same state as Process. src and opt must
+// be specified.
 //
 // Note that filename's directory influences which imports can be chosen,
 // so it is important that filename be accurate.
 func FixImports(filename string, src []byte, opt *Options) (fixes []*ImportFix, err error) {
-	src, opt, err = initialize(filename, src, opt)
-	if err != nil {
-		return nil, err
-	}
-
 	fileSet := token.NewFileSet()
 	file, _, err := parse(fileSet, filename, src, opt)
 	if err != nil {
@@ -85,13 +77,9 @@ func FixImports(filename string, src []byte, opt *Options) (fixes []*ImportFix,
 }
 
 // ApplyFixes applies all of the fixes to the file and formats it. extraMode
-// is added in when parsing the file.
+// is added in when parsing the file. src and opts must be specified, but no
+// env is needed.
 func ApplyFixes(fixes []*ImportFix, filename string, src []byte, opt *Options, extraMode parser.Mode) (formatted []byte, err error) {
-	src, opt, err = initialize(filename, src, opt)
-	if err != nil {
-		return nil, err
-	}
-
 	// Don't use parse() -- we don't care about fragments or statement lists
 	// here, and we need to work with unparseable files.
 	fileSet := token.NewFileSet()
@@ -115,59 +103,9 @@ func ApplyFixes(fixes []*ImportFix, filename string, src []byte, opt *Options, e
 	return formatFile(fileSet, file, src, nil, opt)
 }
 
-// GetAllCandidates gets all of the packages starting with prefix that can be
-// imported by filename, sorted by import path.
-func GetAllCandidates(ctx context.Context, callback func(ImportFix), searchPrefix, filename, filePkg string, opt *Options) error {
-	_, opt, err := initialize(filename, []byte{}, opt)
-	if err != nil {
-		return err
-	}
-	return getAllCandidates(ctx, callback, searchPrefix, filename, filePkg, opt.Env)
-}
-
-// GetPackageExports returns all known packages with name pkg and their exports.
-func GetPackageExports(ctx context.Context, callback func(PackageExport), searchPkg, filename, filePkg string, opt *Options) error {
-	_, opt, err := initialize(filename, []byte{}, opt)
-	if err != nil {
-		return err
-	}
-	return getPackageExports(ctx, callback, searchPkg, filename, filePkg, opt.Env)
-}
-
-// initialize sets the values for opt and src.
-// If they are provided, they are not changed. Otherwise opt is set to the
-// default values and src is read from the file system.
-func initialize(filename string, src []byte, opt *Options) ([]byte, *Options, error) {
-	// Use defaults if opt is nil.
-	if opt == nil {
-		opt = &Options{Comments: true, TabIndent: true, TabWidth: 8}
-	}
-
-	// Set the env if the user has not provided it.
-	if opt.Env == nil {
-		opt.Env = &ProcessEnv{
-			GOPATH:      build.Default.GOPATH,
-			GOROOT:      build.Default.GOROOT,
-			GOFLAGS:     os.Getenv("GOFLAGS"),
-			GO111MODULE: os.Getenv("GO111MODULE"),
-			GOPROXY:     os.Getenv("GOPROXY"),
-			GOSUMDB:     os.Getenv("GOSUMDB"),
-		}
-	}
-	if src == nil {
-		b, err := ioutil.ReadFile(filename)
-		if err != nil {
-			return nil, nil, err
-		}
-		src = b
-	}
-
-	return src, opt, nil
-}
-
 func formatFile(fileSet *token.FileSet, file *ast.File, src []byte, adjust func(orig []byte, src []byte) []byte, opt *Options) ([]byte, error) {
-	mergeImports(opt.Env, fileSet, file)
-	sortImports(opt.Env, fileSet, file)
+	mergeImports(fileSet, file)
+	sortImports(opt.LocalPrefix, fileSet, file)
 	imps := astutil.Imports(fileSet, file)
 	var spacesBefore []string // import paths we need spaces before
 	for _, impSection := range imps {
@@ -178,7 +116,7 @@ func formatFile(fileSet *token.FileSet, file *ast.File, src []byte, adjust func(
 		lastGroup := -1
 		for _, importSpec := range impSection {
 			importPath, _ := strconv.Unquote(importSpec.Path.Value)
-			groupNum := importGroup(opt.Env, importPath)
+			groupNum := importGroup(opt.LocalPrefix, importPath)
 			if groupNum != lastGroup && lastGroup != -1 {
 				spacesBefore = append(spacesBefore, importPath)
 			}

vendor/golang.org/x/tools/internal/imports/mod.go

@@ -15,7 +15,7 @@ import (
 	"strings"
 
 	"golang.org/x/mod/module"
-	"golang.org/x/mod/semver"
+	"golang.org/x/tools/internal/gocommand"
 	"golang.org/x/tools/internal/gopathwalk"
 )
 
@@ -24,31 +24,21 @@ import (
 type ModuleResolver struct {
 	env            *ProcessEnv
 	moduleCacheDir string
-	dummyVendorMod *ModuleJSON // If vendoring is enabled, the pseudo-module that represents the /vendor directory.
+	dummyVendorMod *gocommand.ModuleJSON // If vendoring is enabled, the pseudo-module that represents the /vendor directory.
 	roots          []gopathwalk.Root
 	scanSema       chan struct{} // scanSema prevents concurrent scans and guards scannedRoots.
 	scannedRoots   map[gopathwalk.Root]bool
 
 	initialized   bool
-	main          *ModuleJSON
-	modsByModPath []*ModuleJSON // All modules, ordered by # of path components in module Path...
-	modsByDir     []*ModuleJSON // ...or Dir.
+	main          *gocommand.ModuleJSON
+	modsByModPath []*gocommand.ModuleJSON // All modules, ordered by # of path components in module Path...
+	modsByDir     []*gocommand.ModuleJSON // ...or Dir.
 
 	// moduleCacheCache stores information about the module cache.
 	moduleCacheCache *dirInfoCache
 	otherCache       *dirInfoCache
 }
 
-type ModuleJSON struct {
-	Path      string      // module path
-	Replace   *ModuleJSON // replaced by this module
-	Main      bool        // is this the main module?
-	Indirect  bool        // is this module only an indirect dependency of main module?
-	Dir       string      // directory holding files for this module, if any
-	GoMod     string      // path to go.mod file for this module, if any
-	GoVersion string      // go version used in module
-}
-
 func newModuleResolver(e *ProcessEnv) *ModuleResolver {
 	r := &ModuleResolver{
 		env:      e,
@@ -62,7 +52,18 @@ func (r *ModuleResolver) init() error {
 	if r.initialized {
 		return nil
 	}
-	mainMod, vendorEnabled, err := vendorEnabled(r.env)
+
+	goenv, err := r.env.goEnv()
+	if err != nil {
+		return err
+	}
+	inv := gocommand.Invocation{
+		BuildFlags: r.env.BuildFlags,
+		Env:        r.env.env(),
+		Logf:       r.env.Logf,
+		WorkingDir: r.env.WorkingDir,
+	}
+	mainMod, vendorEnabled, err := gocommand.VendorEnabled(context.TODO(), inv, r.env.GocmdRunner)
 	if err != nil {
 		return err
 	}
@@ -71,18 +72,22 @@ func (r *ModuleResolver) init() error {
 		// Vendor mode is on, so all the non-Main modules are irrelevant,
 		// and we need to search /vendor for everything.
 		r.main = mainMod
-		r.dummyVendorMod = &ModuleJSON{
+		r.dummyVendorMod = &gocommand.ModuleJSON{
 			Path: "",
 			Dir:  filepath.Join(mainMod.Dir, "vendor"),
 		}
-		r.modsByModPath = []*ModuleJSON{mainMod, r.dummyVendorMod}
-		r.modsByDir = []*ModuleJSON{mainMod, r.dummyVendorMod}
+		r.modsByModPath = []*gocommand.ModuleJSON{mainMod, r.dummyVendorMod}
+		r.modsByDir = []*gocommand.ModuleJSON{mainMod, r.dummyVendorMod}
 	} else {
 		// Vendor mode is off, so run go list -m ... to find everything.
 		r.initAllMods()
 	}
 
-	r.moduleCacheDir = filepath.Join(filepath.SplitList(r.env.GOPATH)[0], "/pkg/mod")
+	if gmc := r.env.Env["GOMODCACHE"]; gmc != "" {
+		r.moduleCacheDir = gmc
+	} else {
+		r.moduleCacheDir = filepath.Join(filepath.SplitList(goenv["GOPATH"])[0], "/pkg/mod")
+	}
 
 	sort.Slice(r.modsByModPath, func(i, j int) bool {
 		count := func(x int) int {
@@ -98,7 +103,7 @@ func (r *ModuleResolver) init() error {
 	})
 
 	r.roots = []gopathwalk.Root{
-		{filepath.Join(r.env.GOROOT, "/src"), gopathwalk.RootGOROOT},
+		{filepath.Join(goenv["GOROOT"], "/src"), gopathwalk.RootGOROOT},
 	}
 	if r.main != nil {
 		r.roots = append(r.roots, gopathwalk.Root{r.main.Dir, gopathwalk.RootCurrentModule})
@@ -106,7 +111,7 @@ func (r *ModuleResolver) init() error {
 	if vendorEnabled {
 		r.roots = append(r.roots, gopathwalk.Root{r.dummyVendorMod.Dir, gopathwalk.RootOther})
 	} else {
-		addDep := func(mod *ModuleJSON) {
+		addDep := func(mod *gocommand.ModuleJSON) {
 			if mod.Replace == nil {
 				// This is redundant with the cache, but we'll skip it cheaply enough.
 				r.roots = append(r.roots, gopathwalk.Root{mod.Dir, gopathwalk.RootModuleCache})
@@ -151,7 +156,7 @@ func (r *ModuleResolver) initAllMods() error {
 		return err
 	}
 	for dec := json.NewDecoder(stdout); dec.More(); {
-		mod := &ModuleJSON{}
+		mod := &gocommand.ModuleJSON{}
 		if err := dec.Decode(mod); err != nil {
 			return err
 		}
@@ -197,7 +202,7 @@ func (r *ModuleResolver) ClearForNewMod() {
 
 // findPackage returns the module and directory that contains the package at
 // the given import path, or returns nil, "" if no module is in scope.
-func (r *ModuleResolver) findPackage(importPath string) (*ModuleJSON, string) {
+func (r *ModuleResolver) findPackage(importPath string) (*gocommand.ModuleJSON, string) {
 	// This can't find packages in the stdlib, but that's harmless for all
 	// the existing code paths.
 	for _, m := range r.modsByModPath {
@@ -239,7 +244,7 @@ func (r *ModuleResolver) findPackage(importPath string) (*ModuleJSON, string) {
 		// files in that directory. If not, it could be provided by an
 		// outer module. See #29736.
 		for _, fi := range pkgFiles {
-			if ok, _ := r.env.buildContext().MatchFile(pkgDir, fi.Name()); ok {
+			if ok, _ := r.env.matchFile(pkgDir, fi.Name()); ok {
 				return m, pkgDir
 			}
 		}
@@ -283,7 +288,7 @@ func (r *ModuleResolver) cacheExports(ctx context.Context, env *ProcessEnv, info
 
 // findModuleByDir returns the module that contains dir, or nil if no such
 // module is in scope.
-func (r *ModuleResolver) findModuleByDir(dir string) *ModuleJSON {
+func (r *ModuleResolver) findModuleByDir(dir string) *gocommand.ModuleJSON {
 	// This is quite tricky and may not be correct. dir could be:
 	// - a package in the main module.
 	// - a replace target underneath the main module's directory.
@@ -310,7 +315,7 @@ func (r *ModuleResolver) findModuleByDir(dir string) *ModuleJSON {
 
 // dirIsNestedModule reports if dir is contained in a nested module underneath
 // mod, not actually in mod.
-func (r *ModuleResolver) dirIsNestedModule(dir string, mod *ModuleJSON) bool {
+func (r *ModuleResolver) dirIsNestedModule(dir string, mod *gocommand.ModuleJSON) bool {
 	if !strings.HasPrefix(dir, mod.Dir) {
 		return false
 	}
@@ -490,7 +495,7 @@ func (r *ModuleResolver) scoreImportPath(ctx context.Context, path string) int {
 	return modRelevance(mod)
 }
 
-func modRelevance(mod *ModuleJSON) int {
+func modRelevance(mod *gocommand.ModuleJSON) int {
 	switch {
 	case mod == nil: // out of scope
 		return MaxRelevance - 4
@@ -656,63 +661,3 @@ func modulePath(mod []byte) string {
 	}
 	return "" // missing module path
 }
-
-var modFlagRegexp = regexp.MustCompile(`-mod[ =](\w+)`)
-
-// vendorEnabled indicates if vendoring is enabled.
-// Inspired by setDefaultBuildMod in modload/init.go
-func vendorEnabled(env *ProcessEnv) (*ModuleJSON, bool, error) {
-	mainMod, go114, err := getMainModuleAnd114(env)
-	if err != nil {
-		return nil, false, err
-	}
-	matches := modFlagRegexp.FindStringSubmatch(env.GOFLAGS)
-	var modFlag string
-	if len(matches) != 0 {
-		modFlag = matches[1]
-	}
-	if modFlag != "" {
-		// Don't override an explicit '-mod=' argument.
-		return mainMod, modFlag == "vendor", nil
-	}
-	if mainMod == nil || !go114 {
-		return mainMod, false, nil
-	}
-	// Check 1.14's automatic vendor mode.
-	if fi, err := os.Stat(filepath.Join(mainMod.Dir, "vendor")); err == nil && fi.IsDir() {
-		if mainMod.GoVersion != "" && semver.Compare("v"+mainMod.GoVersion, "v1.14") >= 0 {
-			// The Go version is at least 1.14, and a vendor directory exists.
-			// Set -mod=vendor by default.
-			return mainMod, true, nil
-		}
-	}
-	return mainMod, false, nil
-}
-
-// getMainModuleAnd114 gets the main module's information and whether the
-// go command in use is 1.14+. This is the information needed to figure out
-// if vendoring should be enabled.
-func getMainModuleAnd114(env *ProcessEnv) (*ModuleJSON, bool, error) {
-	const format = `{{.Path}}
-{{.Dir}}
-{{.GoMod}}
-{{.GoVersion}}
-{{range context.ReleaseTags}}{{if eq . "go1.14"}}{{.}}{{end}}{{end}}
-`
-	stdout, err := env.invokeGo(context.TODO(), "list", "-m", "-f", format)
-	if err != nil {
-		return nil, false, nil
-	}
-	lines := strings.Split(stdout.String(), "\n")
-	if len(lines) < 5 {
-		return nil, false, fmt.Errorf("unexpected stdout: %q", stdout)
-	}
-	mod := &ModuleJSON{
-		Path:      lines[0],
-		Dir:       lines[1],
-		GoMod:     lines[2],
-		GoVersion: lines[3],
-		Main:      true,
-	}
-	return mod, lines[4] == "go1.14", nil
-}

vendor/golang.org/x/tools/internal/imports/sortimports.go

@@ -15,7 +15,7 @@ import (
 
 // sortImports sorts runs of consecutive import lines in import blocks in f.
 // It also removes duplicate imports when it is possible to do so without data loss.
-func sortImports(env *ProcessEnv, fset *token.FileSet, f *ast.File) {
+func sortImports(localPrefix string, fset *token.FileSet, f *ast.File) {
 	for i, d := range f.Decls {
 		d, ok := d.(*ast.GenDecl)
 		if !ok || d.Tok != token.IMPORT {
@@ -40,11 +40,11 @@ func sortImports(env *ProcessEnv, fset *token.FileSet, f *ast.File) {
 		for j, s := range d.Specs {
 			if j > i && fset.Position(s.Pos()).Line > 1+fset.Position(d.Specs[j-1].End()).Line {
 				// j begins a new run.  End this one.
-				specs = append(specs, sortSpecs(env, fset, f, d.Specs[i:j])...)
+				specs = append(specs, sortSpecs(localPrefix, fset, f, d.Specs[i:j])...)
 				i = j
 			}
 		}
-		specs = append(specs, sortSpecs(env, fset, f, d.Specs[i:])...)
+		specs = append(specs, sortSpecs(localPrefix, fset, f, d.Specs[i:])...)
 		d.Specs = specs
 
 		// Deduping can leave a blank line before the rparen; clean that up.
@@ -60,7 +60,7 @@ func sortImports(env *ProcessEnv, fset *token.FileSet, f *ast.File) {
 
 // mergeImports merges all the import declarations into the first one.
 // Taken from golang.org/x/tools/ast/astutil.
-func mergeImports(env *ProcessEnv, fset *token.FileSet, f *ast.File) {
+func mergeImports(fset *token.FileSet, f *ast.File) {
 	if len(f.Decls) <= 1 {
 		return
 	}
@@ -142,7 +142,7 @@ type posSpan struct {
 	End   token.Pos
 }
 
-func sortSpecs(env *ProcessEnv, fset *token.FileSet, f *ast.File, specs []ast.Spec) []ast.Spec {
+func sortSpecs(localPrefix string, fset *token.FileSet, f *ast.File, specs []ast.Spec) []ast.Spec {
 	// Can't short-circuit here even if specs are already sorted,
 	// since they might yet need deduplication.
 	// A lone import, however, may be safely ignored.
@@ -191,7 +191,7 @@ func sortSpecs(env *ProcessEnv, fset *token.FileSet, f *ast.File, specs []ast.Sp
 	// Reassign the import paths to have the same position sequence.
 	// Reassign each comment to abut the end of its spec.
 	// Sort the comments by new position.
-	sort.Sort(byImportSpec{env, specs})
+	sort.Sort(byImportSpec{localPrefix, specs})
 
 	// Dedup. Thanks to our sorting, we can just consider
 	// adjacent pairs of imports.
@@ -245,8 +245,8 @@ func sortSpecs(env *ProcessEnv, fset *token.FileSet, f *ast.File, specs []ast.Sp
 }
 
 type byImportSpec struct {
-	env   *ProcessEnv
-	specs []ast.Spec // slice of *ast.ImportSpec
+	localPrefix string
+	specs       []ast.Spec // slice of *ast.ImportSpec
 }
 
 func (x byImportSpec) Len() int      { return len(x.specs) }
@@ -255,8 +255,8 @@ func (x byImportSpec) Less(i, j int) bool {
 	ipath := importPath(x.specs[i])
 	jpath := importPath(x.specs[j])
 
-	igroup := importGroup(x.env, ipath)
-	jgroup := importGroup(x.env, jpath)
+	igroup := importGroup(x.localPrefix, ipath)
+	jgroup := importGroup(x.localPrefix, jpath)
 	if igroup != jgroup {
 		return igroup < jgroup
 	}

vendor/golang.org/x/tools/internal/imports/zstdlib.go

@@ -56,6 +56,7 @@ var stdlib = map[string][]string{
 	},
 	"bufio": []string{
 		"ErrAdvanceTooFar",
+		"ErrBadReadCount",
 		"ErrBufferFull",
 		"ErrFinalToken",
 		"ErrInvalidUnreadByte",
@@ -303,7 +304,9 @@ var stdlib = map[string][]string{
 		"PrivateKey",
 		"PublicKey",
 		"Sign",
+		"SignASN1",
 		"Verify",
+		"VerifyASN1",
 	},
 	"crypto/ed25519": []string{
 		"GenerateKey",
@@ -322,11 +325,13 @@ var stdlib = map[string][]string{
 		"CurveParams",
 		"GenerateKey",
 		"Marshal",
+		"MarshalCompressed",
 		"P224",
 		"P256",
 		"P384",
 		"P521",
 		"Unmarshal",
+		"UnmarshalCompressed",
 	},
 	"crypto/hmac": []string{
 		"Equal",
@@ -415,6 +420,9 @@ var stdlib = map[string][]string{
 	"crypto/tls": []string{
 		"Certificate",
 		"CertificateRequestInfo",
+		"CipherSuite",
+		"CipherSuiteName",
+		"CipherSuites",
 		"Client",
 		"ClientAuthType",
 		"ClientHelloInfo",
@@ -429,11 +437,13 @@ var stdlib = map[string][]string{
 		"CurveP521",
 		"Dial",
 		"DialWithDialer",
+		"Dialer",
 		"ECDSAWithP256AndSHA256",
 		"ECDSAWithP384AndSHA384",
 		"ECDSAWithP521AndSHA512",
 		"ECDSAWithSHA1",
 		"Ed25519",
+		"InsecureCipherSuites",
 		"Listen",
 		"LoadX509KeyPair",
 		"NewLRUClientSessionCache",
@@ -465,6 +475,7 @@ var stdlib = map[string][]string{
 		"TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA",
 		"TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
 		"TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305",
+		"TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256",
 		"TLS_ECDHE_ECDSA_WITH_RC4_128_SHA",
 		"TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA",
 		"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA",
@@ -473,6 +484,7 @@ var stdlib = map[string][]string{
 		"TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA",
 		"TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384",
 		"TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305",
+		"TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256",
 		"TLS_ECDHE_RSA_WITH_RC4_128_SHA",
 		"TLS_FALLBACK_SCSV",
 		"TLS_RSA_WITH_3DES_EDE_CBC_SHA",
@@ -501,6 +513,7 @@ var stdlib = map[string][]string{
 		"ConstraintViolationError",
 		"CreateCertificate",
 		"CreateCertificateRequest",
+		"CreateRevocationList",
 		"DSA",
 		"DSAWithSHA1",
 		"DSAWithSHA256",
@@ -575,6 +588,7 @@ var stdlib = map[string][]string{
 		"PublicKeyAlgorithm",
 		"PureEd25519",
 		"RSA",
+		"RevocationList",
 		"SHA1WithRSA",
 		"SHA256WithRSA",
 		"SHA256WithRSAPSS",
@@ -688,6 +702,7 @@ var stdlib = map[string][]string{
 		"String",
 		"Tx",
 		"TxOptions",
+		"Validator",
 		"Value",
 		"ValueConverter",
 		"Valuer",
@@ -698,36 +713,65 @@ var stdlib = map[string][]string{
 		"Attr",
 		"AttrAbstractOrigin",
 		"AttrAccessibility",
+		"AttrAddrBase",
 		"AttrAddrClass",
+		"AttrAlignment",
 		"AttrAllocated",
 		"AttrArtificial",
 		"AttrAssociated",
 		"AttrBaseTypes",
+		"AttrBinaryScale",
 		"AttrBitOffset",
 		"AttrBitSize",
 		"AttrByteSize",
+		"AttrCallAllCalls",
+		"AttrCallAllSourceCalls",
+		"AttrCallAllTailCalls",
 		"AttrCallColumn",
+		"AttrCallDataLocation",
+		"AttrCallDataValue",
 		"AttrCallFile",
 		"AttrCallLine",
+		"AttrCallOrigin",
+		"AttrCallPC",
+		"AttrCallParameter",
+		"AttrCallReturnPC",
+		"AttrCallTailCall",
+		"AttrCallTarget",
+		"AttrCallTargetClobbered",
+		"AttrCallValue",
 		"AttrCalling",
 		"AttrCommonRef",
 		"AttrCompDir",
+		"AttrConstExpr",
 		"AttrConstValue",
 		"AttrContainingType",
 		"AttrCount",
+		"AttrDataBitOffset",
 		"AttrDataLocation",
 		"AttrDataMemberLoc",
+		"AttrDecimalScale",
+		"AttrDecimalSign",
 		"AttrDeclColumn",
 		"AttrDeclFile",
 		"AttrDeclLine",
 		"AttrDeclaration",
 		"AttrDefaultValue",
+		"AttrDefaulted",
+		"AttrDeleted",
 		"AttrDescription",
+		"AttrDigitCount",
 		"AttrDiscr",
 		"AttrDiscrList",
 		"AttrDiscrValue",
+		"AttrDwoName",
+		"AttrElemental",
 		"AttrEncoding",
+		"AttrEndianity",
 		"AttrEntrypc",
+		"AttrEnumClass",
+		"AttrExplicit",
+		"AttrExportSymbols",
 		"AttrExtension",
 		"AttrExternal",
 		"AttrFrameBase",
@@ -738,27 +782,47 @@ var stdlib = map[string][]string{
 		"AttrInline",
 		"AttrIsOptional",
 		"AttrLanguage",
+		"AttrLinkageName",
 		"AttrLocation",
+		"AttrLoclistsBase",
 		"AttrLowerBound",
 		"AttrLowpc",
 		"AttrMacroInfo",
+		"AttrMacros",
+		"AttrMainSubprogram",
+		"AttrMutable",
 		"AttrName",
 		"AttrNamelistItem",
+		"AttrNoreturn",
+		"AttrObjectPointer",
 		"AttrOrdering",
+		"AttrPictureString",
 		"AttrPriority",
 		"AttrProducer",
 		"AttrPrototyped",
+		"AttrPure",
 		"AttrRanges",
+		"AttrRank",
+		"AttrRecursive",
+		"AttrReference",
 		"AttrReturnAddr",
+		"AttrRnglistsBase",
+		"AttrRvalueReference",
 		"AttrSegment",
 		"AttrSibling",
+		"AttrSignature",
+		"AttrSmall",
 		"AttrSpecification",
 		"AttrStartScope",
 		"AttrStaticLink",
 		"AttrStmtList",
+		"AttrStrOffsetsBase",
 		"AttrStride",
 		"AttrStrideSize",
 		"AttrStringLength",
+		"AttrStringLengthBitSize",
+		"AttrStringLengthByteSize",
+		"AttrThreadsScaled",
 		"AttrTrampoline",
 		"AttrType",
 		"AttrUpperBound",
@@ -772,18 +836,23 @@ var stdlib = map[string][]string{
 		"BoolType",
 		"CharType",
 		"Class",
+		"ClassAddrPtr",
 		"ClassAddress",
 		"ClassBlock",
 		"ClassConstant",
 		"ClassExprLoc",
 		"ClassFlag",
 		"ClassLinePtr",
+		"ClassLocList",
 		"ClassLocListPtr",
 		"ClassMacPtr",
 		"ClassRangeListPtr",
 		"ClassReference",
 		"ClassReferenceAlt",
 		"ClassReferenceSig",
+		"ClassRngList",
+		"ClassRngListsPtr",
+		"ClassStrOffsetsPtr",
 		"ClassString",
 		"ClassStringAlt",
 		"ClassUnknown",
@@ -814,9 +883,13 @@ var stdlib = map[string][]string{
 		"Tag",
 		"TagAccessDeclaration",
 		"TagArrayType",
+		"TagAtomicType",
 		"TagBaseType",
+		"TagCallSite",
+		"TagCallSiteParameter",
 		"TagCatchDwarfBlock",
 		"TagClassType",
+		"TagCoarrayType",
 		"TagCommonDwarfBlock",
 		"TagCommonInclusion",
 		"TagCompileUnit",
@@ -824,12 +897,15 @@ var stdlib = map[string][]string{
 		"TagConstType",
 		"TagConstant",
 		"TagDwarfProcedure",
+		"TagDynamicType",
 		"TagEntryPoint",
 		"TagEnumerationType",
 		"TagEnumerator",
 		"TagFileType",
 		"TagFormalParameter",
 		"TagFriend",
+		"TagGenericSubrange",
+		"TagImmutableType",
 		"TagImportedDeclaration",
 		"TagImportedModule",
 		"TagImportedUnit",
@@ -853,6 +929,7 @@ var stdlib = map[string][]string{
 		"TagRvalueReferenceType",
 		"TagSetType",
 		"TagSharedType",
+		"TagSkeletonUnit",
 		"TagStringType",
 		"TagStructType",
 		"TagSubprogram",
@@ -2281,6 +2358,27 @@ var stdlib = map[string][]string{
 		"IMAGE_DIRECTORY_ENTRY_RESOURCE",
 		"IMAGE_DIRECTORY_ENTRY_SECURITY",
 		"IMAGE_DIRECTORY_ENTRY_TLS",
+		"IMAGE_DLLCHARACTERISTICS_APPCONTAINER",
+		"IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE",
+		"IMAGE_DLLCHARACTERISTICS_FORCE_INTEGRITY",
+		"IMAGE_DLLCHARACTERISTICS_GUARD_CF",
+		"IMAGE_DLLCHARACTERISTICS_HIGH_ENTROPY_VA",
+		"IMAGE_DLLCHARACTERISTICS_NO_BIND",
+		"IMAGE_DLLCHARACTERISTICS_NO_ISOLATION",
+		"IMAGE_DLLCHARACTERISTICS_NO_SEH",
+		"IMAGE_DLLCHARACTERISTICS_NX_COMPAT",
+		"IMAGE_DLLCHARACTERISTICS_TERMINAL_SERVER_AWARE",
+		"IMAGE_DLLCHARACTERISTICS_WDM_DRIVER",
+		"IMAGE_FILE_32BIT_MACHINE",
+		"IMAGE_FILE_AGGRESIVE_WS_TRIM",
+		"IMAGE_FILE_BYTES_REVERSED_HI",
+		"IMAGE_FILE_BYTES_REVERSED_LO",
+		"IMAGE_FILE_DEBUG_STRIPPED",
+		"IMAGE_FILE_DLL",
+		"IMAGE_FILE_EXECUTABLE_IMAGE",
+		"IMAGE_FILE_LARGE_ADDRESS_AWARE",
+		"IMAGE_FILE_LINE_NUMS_STRIPPED",
+		"IMAGE_FILE_LOCAL_SYMS_STRIPPED",
 		"IMAGE_FILE_MACHINE_AM33",
 		"IMAGE_FILE_MACHINE_AMD64",
 		"IMAGE_FILE_MACHINE_ARM",
@@ -2303,6 +2401,25 @@ var stdlib = map[string][]string{
 		"IMAGE_FILE_MACHINE_THUMB",
 		"IMAGE_FILE_MACHINE_UNKNOWN",
 		"IMAGE_FILE_MACHINE_WCEMIPSV2",
+		"IMAGE_FILE_NET_RUN_FROM_SWAP",
+		"IMAGE_FILE_RELOCS_STRIPPED",
+		"IMAGE_FILE_REMOVABLE_RUN_FROM_SWAP",
+		"IMAGE_FILE_SYSTEM",
+		"IMAGE_FILE_UP_SYSTEM_ONLY",
+		"IMAGE_SUBSYSTEM_EFI_APPLICATION",
+		"IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER",
+		"IMAGE_SUBSYSTEM_EFI_ROM",
+		"IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER",
+		"IMAGE_SUBSYSTEM_NATIVE",
+		"IMAGE_SUBSYSTEM_NATIVE_WINDOWS",
+		"IMAGE_SUBSYSTEM_OS2_CUI",
+		"IMAGE_SUBSYSTEM_POSIX_CUI",
+		"IMAGE_SUBSYSTEM_UNKNOWN",
+		"IMAGE_SUBSYSTEM_WINDOWS_BOOT_APPLICATION",
+		"IMAGE_SUBSYSTEM_WINDOWS_CE_GUI",
+		"IMAGE_SUBSYSTEM_WINDOWS_CUI",
+		"IMAGE_SUBSYSTEM_WINDOWS_GUI",
+		"IMAGE_SUBSYSTEM_XBOX",
 		"ImportDirectory",
 		"NewFile",
 		"Open",
@@ -2359,6 +2476,7 @@ var stdlib = map[string][]string{
 		"RawValue",
 		"StructuralError",
 		"SyntaxError",
+		"TagBMPString",
 		"TagBitString",
 		"TagBoolean",
 		"TagEnum",
@@ -2787,6 +2905,7 @@ var stdlib = map[string][]string{
 		"IsPredeclared",
 		"Mode",
 		"New",
+		"NewFromFiles",
 		"Note",
 		"Package",
 		"PreserveAST",
@@ -3115,6 +3234,11 @@ var stdlib = map[string][]string{
 		"New64",
 		"New64a",
 	},
+	"hash/maphash": []string{
+		"Hash",
+		"MakeSeed",
+		"Seed",
+	},
 	"html": []string{
 		"EscapeString",
 		"UnescapeString",
@@ -3367,6 +3491,7 @@ var stdlib = map[string][]string{
 		"Ldate",
 		"Llongfile",
 		"Lmicroseconds",
+		"Lmsgprefix",
 		"Logger",
 		"Lshortfile",
 		"LstdFlags",
@@ -3443,6 +3568,7 @@ var stdlib = map[string][]string{
 		"Exp",
 		"Exp2",
 		"Expm1",
+		"FMA",
 		"Float32bits",
 		"Float32frombits",
 		"Float64bits",
@@ -3567,6 +3693,9 @@ var stdlib = map[string][]string{
 		"OnesCount32",
 		"OnesCount64",
 		"OnesCount8",
+		"Rem",
+		"Rem32",
+		"Rem64",
 		"Reverse",
 		"Reverse16",
 		"Reverse32",
@@ -4108,6 +4237,7 @@ var stdlib = map[string][]string{
 		"DevNull",
 		"Environ",
 		"ErrClosed",
+		"ErrDeadlineExceeded",
 		"ErrExist",
 		"ErrInvalid",
 		"ErrNoDeadline",
@@ -4566,6 +4696,7 @@ var stdlib = map[string][]string{
 		"ErrRange",
 		"ErrSyntax",
 		"FormatBool",
+		"FormatComplex",
 		"FormatFloat",
 		"FormatInt",
 		"FormatUint",
@@ -4575,6 +4706,7 @@ var stdlib = map[string][]string{
 		"Itoa",
 		"NumError",
 		"ParseBool",
+		"ParseComplex",
 		"ParseFloat",
 		"ParseInt",
 		"ParseUint",
@@ -5140,7 +5272,10 @@ var stdlib = map[string][]string{
 		"CTL_NET",
 		"CTL_QUERY",
 		"CTRL_BREAK_EVENT",
+		"CTRL_CLOSE_EVENT",
 		"CTRL_C_EVENT",
+		"CTRL_LOGOFF_EVENT",
+		"CTRL_SHUTDOWN_EVENT",
 		"CancelIo",
 		"CancelIoEx",
 		"CertAddCertificateContextToStore",
@@ -10112,6 +10247,7 @@ var stdlib = map[string][]string{
 		"Duployan",
 		"Egyptian_Hieroglyphs",
 		"Elbasan",
+		"Elymaic",
 		"Ethiopic",
 		"Extender",
 		"FoldCategory",
@@ -10215,6 +10351,7 @@ var stdlib = map[string][]string{
 		"Myanmar",
 		"N",
 		"Nabataean",
+		"Nandinagari",
 		"Nd",
 		"New_Tai_Lue",
 		"Newa",
@@ -10224,6 +10361,7 @@ var stdlib = map[string][]string{
 		"Noncharacter_Code_Point",
 		"Number",
 		"Nushu",
+		"Nyiakeng_Puachue_Hmong",
 		"Ogham",
 		"Ol_Chiki",
 		"Old_Hungarian",
@@ -10331,6 +10469,7 @@ var stdlib = map[string][]string{
 		"Vai",
 		"Variation_Selector",
 		"Version",
+		"Wancho",
 		"Warang_Citi",
 		"White_Space",
 		"Yi",

vendor/golang.org/x/tools/internal/lsp/fuzzy/input.go

@@ -0,0 +1,168 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package fuzzy
+
+import (
+	"unicode"
+)
+
+// RuneRole specifies the role of a rune in the context of an input.
+type RuneRole byte
+
+const (
+	// RNone specifies a rune without any role in the input (i.e., whitespace/non-ASCII).
+	RNone RuneRole = iota
+	// RSep specifies a rune with the role of segment separator.
+	RSep
+	// RTail specifies a rune which is a lower-case tail in a word in the input.
+	RTail
+	// RUCTail specifies a rune which is an upper-case tail in a word in the input.
+	RUCTail
+	// RHead specifies a rune which is the first character in a word in the input.
+	RHead
+)
+
+// RuneRoles detects the roles of each byte rune in an input string and stores it in the output
+// slice. The rune role depends on the input type. Stops when it parsed all the runes in the string
+// or when it filled the output. If output is nil, then it gets created.
+func RuneRoles(str string, reuse []RuneRole) []RuneRole {
+	var output []RuneRole
+	if cap(reuse) < len(str) {
+		output = make([]RuneRole, 0, len(str))
+	} else {
+		output = reuse[:0]
+	}
+
+	prev, prev2 := rtNone, rtNone
+	for i := 0; i < len(str); i++ {
+		r := rune(str[i])
+
+		role := RNone
+
+		curr := rtLower
+		if str[i] <= unicode.MaxASCII {
+			curr = runeType(rt[str[i]] - '0')
+		}
+
+		if curr == rtLower {
+			if prev == rtNone || prev == rtPunct {
+				role = RHead
+			} else {
+				role = RTail
+			}
+		} else if curr == rtUpper {
+			role = RHead
+
+			if prev == rtUpper {
+				// This and previous characters are both upper case.
+
+				if i+1 == len(str) {
+					// This is last character, previous was also uppercase -> this is UCTail
+					// i.e., (current char is C): aBC / BC / ABC
+					role = RUCTail
+				}
+			}
+		} else if curr == rtPunct {
+			switch r {
+			case '.', ':':
+				role = RSep
+			}
+		}
+		if curr != rtLower {
+			if i > 1 && output[i-1] == RHead && prev2 == rtUpper && (output[i-2] == RHead || output[i-2] == RUCTail) {
+				// The previous two characters were uppercase. The current one is not a lower case, so the
+				// previous one can't be a HEAD. Make it a UCTail.
+				// i.e., (last char is current char - B must be a UCTail): ABC / ZABC / AB.
+				output[i-1] = RUCTail
+			}
+		}
+
+		output = append(output, role)
+		prev2 = prev
+		prev = curr
+	}
+	return output
+}
+
+type runeType byte
+
+const (
+	rtNone runeType = iota
+	rtPunct
+	rtLower
+	rtUpper
+)
+
+const rt = "00000000000000000000000000000000000000000000001122222222221000000333333333333333333333333330000002222222222222222222222222200000"
+
+// LastSegment returns the substring representing the last segment from the input, where each
+// byte has an associated RuneRole in the roles slice. This makes sense only for inputs of Symbol
+// or Filename type.
+func LastSegment(input string, roles []RuneRole) string {
+	// Exclude ending separators.
+	end := len(input) - 1
+	for end >= 0 && roles[end] == RSep {
+		end--
+	}
+	if end < 0 {
+		return ""
+	}
+
+	start := end - 1
+	for start >= 0 && roles[start] != RSep {
+		start--
+	}
+
+	return input[start+1 : end+1]
+}
+
+// ToLower transforms the input string to lower case, which is stored in the output byte slice.
+// The lower casing considers only ASCII values - non ASCII values are left unmodified.
+// Stops when parsed all input or when it filled the output slice. If output is nil, then it gets
+// created.
+func ToLower(input string, reuse []byte) []byte {
+	output := reuse
+	if cap(reuse) < len(input) {
+		output = make([]byte, len(input))
+	}
+
+	for i := 0; i < len(input); i++ {
+		r := rune(input[i])
+		if r <= unicode.MaxASCII {
+			if 'A' <= r && r <= 'Z' {
+				r += 'a' - 'A'
+			}
+		}
+		output[i] = byte(r)
+	}
+	return output[:len(input)]
+}
+
+// WordConsumer defines a consumer for a word delimited by the [start,end) byte offsets in an input
+// (start is inclusive, end is exclusive).
+type WordConsumer func(start, end int)
+
+// Words find word delimiters in an input based on its bytes' mappings to rune roles. The offset
+// delimiters for each word are fed to the provided consumer function.
+func Words(roles []RuneRole, consume WordConsumer) {
+	var wordStart int
+	for i, r := range roles {
+		switch r {
+		case RUCTail, RTail:
+		case RHead, RNone, RSep:
+			if i != wordStart {
+				consume(wordStart, i)
+			}
+			wordStart = i
+			if r != RHead {
+				// Skip this character.
+				wordStart = i + 1
+			}
+		}
+	}
+	if wordStart != len(roles) {
+		consume(wordStart, len(roles))
+	}
+}

vendor/golang.org/x/tools/internal/lsp/fuzzy/matcher.go

@@ -0,0 +1,398 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package fuzzy implements a fuzzy matching algorithm.
+package fuzzy
+
+import (
+	"bytes"
+	"fmt"
+)
+
+const (
+	// MaxInputSize is the maximum size of the input scored against the fuzzy matcher. Longer inputs
+	// will be truncated to this size.
+	MaxInputSize = 127
+	// MaxPatternSize is the maximum size of the pattern used to construct the fuzzy matcher. Longer
+	// inputs are truncated to this size.
+	MaxPatternSize = 63
+)
+
+type scoreVal int
+
+func (s scoreVal) val() int {
+	return int(s) >> 1
+}
+
+func (s scoreVal) prevK() int {
+	return int(s) & 1
+}
+
+func score(val int, prevK int /*0 or 1*/) scoreVal {
+	return scoreVal(val<<1 + prevK)
+}
+
+// Matcher implements a fuzzy matching algorithm for scoring candidates against a pattern.
+// The matcher does not support parallel usage.
+type Matcher struct {
+	pattern       string
+	patternLower  []byte // lower-case version of the pattern
+	patternShort  []byte // first characters of the pattern
+	caseSensitive bool   // set if the pattern is mix-cased
+
+	patternRoles []RuneRole // the role of each character in the pattern
+	roles        []RuneRole // the role of each character in the tested string
+
+	scores [MaxInputSize + 1][MaxPatternSize + 1][2]scoreVal
+
+	scoreScale float32
+
+	lastCandidateLen     int // in bytes
+	lastCandidateMatched bool
+
+	// Here we save the last candidate in lower-case. This is basically a byte slice we reuse for
+	// performance reasons, so the slice is not reallocated for every candidate.
+	lowerBuf [MaxInputSize]byte
+	rolesBuf [MaxInputSize]RuneRole
+}
+
+func (m *Matcher) bestK(i, j int) int {
+	if m.scores[i][j][0].val() < m.scores[i][j][1].val() {
+		return 1
+	}
+	return 0
+}
+
+// NewMatcher returns a new fuzzy matcher for scoring candidates against the provided pattern.
+func NewMatcher(pattern string) *Matcher {
+	if len(pattern) > MaxPatternSize {
+		pattern = pattern[:MaxPatternSize]
+	}
+
+	m := &Matcher{
+		pattern:      pattern,
+		patternLower: ToLower(pattern, nil),
+	}
+
+	for i, c := range m.patternLower {
+		if pattern[i] != c {
+			m.caseSensitive = true
+			break
+		}
+	}
+
+	if len(pattern) > 3 {
+		m.patternShort = m.patternLower[:3]
+	} else {
+		m.patternShort = m.patternLower
+	}
+
+	m.patternRoles = RuneRoles(pattern, nil)
+
+	if len(pattern) > 0 {
+		maxCharScore := 4
+		m.scoreScale = 1 / float32(maxCharScore*len(pattern))
+	}
+
+	return m
+}
+
+// Score returns the score returned by matching the candidate to the pattern.
+// This is not designed for parallel use. Multiple candidates must be scored sequentially.
+// Returns a score between 0 and 1 (0 - no match, 1 - perfect match).
+func (m *Matcher) Score(candidate string) float32 {
+	if len(candidate) > MaxInputSize {
+		candidate = candidate[:MaxInputSize]
+	}
+	lower := ToLower(candidate, m.lowerBuf[:])
+	m.lastCandidateLen = len(candidate)
+
+	if len(m.pattern) == 0 {
+		// Empty patterns perfectly match candidates.
+		return 1
+	}
+
+	if m.match(candidate, lower) {
+		sc := m.computeScore(candidate, lower)
+		if sc > minScore/2 && !m.poorMatch() {
+			m.lastCandidateMatched = true
+			if len(m.pattern) == len(candidate) {
+				// Perfect match.
+				return 1
+			}
+
+			if sc < 0 {
+				sc = 0
+			}
+			normalizedScore := float32(sc) * m.scoreScale
+			if normalizedScore > 1 {
+				normalizedScore = 1
+			}
+
+			return normalizedScore
+		}
+	}
+
+	m.lastCandidateMatched = false
+	return -1
+}
+
+const minScore = -10000
+
+// MatchedRanges returns matches ranges for the last scored string as a flattened array of
+// [begin, end) byte offset pairs.
+func (m *Matcher) MatchedRanges() []int {
+	if len(m.pattern) == 0 || !m.lastCandidateMatched {
+		return nil
+	}
+	i, j := m.lastCandidateLen, len(m.pattern)
+	if m.scores[i][j][0].val() < minScore/2 && m.scores[i][j][1].val() < minScore/2 {
+		return nil
+	}
+
+	var ret []int
+	k := m.bestK(i, j)
+	for i > 0 {
+		take := (k == 1)
+		k = m.scores[i][j][k].prevK()
+		if take {
+			if len(ret) == 0 || ret[len(ret)-1] != i {
+				ret = append(ret, i)
+				ret = append(ret, i-1)
+			} else {
+				ret[len(ret)-1] = i - 1
+			}
+			j--
+		}
+		i--
+	}
+	// Reverse slice.
+	for i := 0; i < len(ret)/2; i++ {
+		ret[i], ret[len(ret)-1-i] = ret[len(ret)-1-i], ret[i]
+	}
+	return ret
+}
+
+func (m *Matcher) match(candidate string, candidateLower []byte) bool {
+	i, j := 0, 0
+	for ; i < len(candidateLower) && j < len(m.patternLower); i++ {
+		if candidateLower[i] == m.patternLower[j] {
+			j++
+		}
+	}
+	if j != len(m.patternLower) {
+		return false
+	}
+
+	// The input passes the simple test against pattern, so it is time to classify its characters.
+	// Character roles are used below to find the last segment.
+	m.roles = RuneRoles(candidate, m.rolesBuf[:])
+
+	return true
+}
+
+func (m *Matcher) computeScore(candidate string, candidateLower []byte) int {
+	pattLen, candLen := len(m.pattern), len(candidate)
+
+	for j := 0; j <= len(m.pattern); j++ {
+		m.scores[0][j][0] = minScore << 1
+		m.scores[0][j][1] = minScore << 1
+	}
+	m.scores[0][0][0] = score(0, 0) // Start with 0.
+
+	segmentsLeft, lastSegStart := 1, 0
+	for i := 0; i < candLen; i++ {
+		if m.roles[i] == RSep {
+			segmentsLeft++
+			lastSegStart = i + 1
+		}
+	}
+
+	// A per-character bonus for a consecutive match.
+	consecutiveBonus := 2
+	wordIdx := 0 // Word count within segment.
+	for i := 1; i <= candLen; i++ {
+
+		role := m.roles[i-1]
+		isHead := role == RHead
+
+		if isHead {
+			wordIdx++
+		} else if role == RSep && segmentsLeft > 1 {
+			wordIdx = 0
+			segmentsLeft--
+		}
+
+		var skipPenalty int
+		if i == 1 || (i-1) == lastSegStart {
+			// Skipping the start of first or last segment.
+			skipPenalty++
+		}
+
+		for j := 0; j <= pattLen; j++ {
+			// By default, we don't have a match. Fill in the skip data.
+			m.scores[i][j][1] = minScore << 1
+
+			// Compute the skip score.
+			k := 0
+			if m.scores[i-1][j][0].val() < m.scores[i-1][j][1].val() {
+				k = 1
+			}
+
+			skipScore := m.scores[i-1][j][k].val()
+			// Do not penalize missing characters after the last matched segment.
+			if j != pattLen {
+				skipScore -= skipPenalty
+			}
+			m.scores[i][j][0] = score(skipScore, k)
+
+			if j == 0 || candidateLower[i-1] != m.patternLower[j-1] {
+				// Not a match.
+				continue
+			}
+			pRole := m.patternRoles[j-1]
+
+			if role == RTail && pRole == RHead {
+				if j > 1 {
+					// Not a match: a head in the pattern matches a tail character in the candidate.
+					continue
+				}
+				// Special treatment for the first character of the pattern. We allow
+				// matches in the middle of a word if they are long enough, at least
+				// min(3, pattern.length) characters.
+				if !bytes.HasPrefix(candidateLower[i-1:], m.patternShort) {
+					continue
+				}
+			}
+
+			// Compute the char score.
+			var charScore int
+			// Bonus 1: the char is in the candidate's last segment.
+			if segmentsLeft <= 1 {
+				charScore++
+			}
+			// Bonus 2: Case match or a Head in the pattern aligns with one in the word.
+			// Single-case patterns lack segmentation signals and we assume any character
+			// can be a head of a segment.
+			if candidate[i-1] == m.pattern[j-1] || role == RHead && (!m.caseSensitive || pRole == RHead) {
+				charScore++
+			}
+
+			// Penalty 1: pattern char is Head, candidate char is Tail.
+			if role == RTail && pRole == RHead {
+				charScore--
+			}
+			// Penalty 2: first pattern character matched in the middle of a word.
+			if j == 1 && role == RTail {
+				charScore -= 4
+			}
+
+			// Third dimension encodes whether there is a gap between the previous match and the current
+			// one.
+			for k := 0; k < 2; k++ {
+				sc := m.scores[i-1][j-1][k].val() + charScore
+
+				isConsecutive := k == 1 || i-1 == 0 || i-1 == lastSegStart
+				if isConsecutive {
+					// Bonus 3: a consecutive match. First character match also gets a bonus to
+					// ensure prefix final match score normalizes to 1.0.
+					// Logically, this is a part of charScore, but we have to compute it here because it
+					// only applies for consecutive matches (k == 1).
+					sc += consecutiveBonus
+				}
+				if k == 0 {
+					// Penalty 3: Matching inside a segment (and previous char wasn't matched). Penalize for the lack
+					// of alignment.
+					if role == RTail || role == RUCTail {
+						sc -= 3
+					}
+				}
+
+				if sc > m.scores[i][j][1].val() {
+					m.scores[i][j][1] = score(sc, k)
+				}
+			}
+		}
+	}
+
+	result := m.scores[len(candidate)][len(m.pattern)][m.bestK(len(candidate), len(m.pattern))].val()
+
+	return result
+}
+
+// ScoreTable returns the score table computed for the provided candidate. Used only for debugging.
+func (m *Matcher) ScoreTable(candidate string) string {
+	var buf bytes.Buffer
+
+	var line1, line2, separator bytes.Buffer
+	line1.WriteString("\t")
+	line2.WriteString("\t")
+	for j := 0; j < len(m.pattern); j++ {
+		line1.WriteString(fmt.Sprintf("%c\t\t", m.pattern[j]))
+		separator.WriteString("----------------")
+	}
+
+	buf.WriteString(line1.String())
+	buf.WriteString("\n")
+	buf.WriteString(separator.String())
+	buf.WriteString("\n")
+
+	for i := 1; i <= len(candidate); i++ {
+		line1.Reset()
+		line2.Reset()
+
+		line1.WriteString(fmt.Sprintf("%c\t", candidate[i-1]))
+		line2.WriteString("\t")
+
+		for j := 1; j <= len(m.pattern); j++ {
+			line1.WriteString(fmt.Sprintf("M%6d(%c)\t", m.scores[i][j][0].val(), dir(m.scores[i][j][0].prevK())))
+			line2.WriteString(fmt.Sprintf("H%6d(%c)\t", m.scores[i][j][1].val(), dir(m.scores[i][j][1].prevK())))
+		}
+		buf.WriteString(line1.String())
+		buf.WriteString("\n")
+		buf.WriteString(line2.String())
+		buf.WriteString("\n")
+		buf.WriteString(separator.String())
+		buf.WriteString("\n")
+	}
+
+	return buf.String()
+}
+
+func dir(prevK int) rune {
+	if prevK == 0 {
+		return 'M'
+	}
+	return 'H'
+}
+
+func (m *Matcher) poorMatch() bool {
+	if len(m.pattern) < 2 {
+		return false
+	}
+
+	i, j := m.lastCandidateLen, len(m.pattern)
+	k := m.bestK(i, j)
+
+	var counter, len int
+	for i > 0 {
+		take := (k == 1)
+		k = m.scores[i][j][k].prevK()
+		if take {
+			len++
+			if k == 0 && len < 3 && m.roles[i-1] == RTail {
+				// Short match in the middle of a word
+				counter++
+				if counter > 1 {
+					return true
+				}
+			}
+			j--
+		} else {
+			len = 0
+		}
+		i--
+	}
+	return false
+}

vendor/golang.org/x/tools/internal/packagesinternal/packages.go

@@ -1,27 +1,14 @@
 // Package packagesinternal exposes internal-only fields from go/packages.
 package packagesinternal
 
-import "time"
-
-// Fields must match go list;
-type Module struct {
-	Path      string       // module path
-	Version   string       // module version
-	Versions  []string     // available module versions (with -versions)
-	Replace   *Module      // replaced by this module
-	Time      *time.Time   // time version was created
-	Update    *Module      // available update, if any (with -u)
-	Main      bool         // is this the main module?
-	Indirect  bool         // is this module only an indirect dependency of main module?
-	Dir       string       // directory holding files for this module, if any
-	GoMod     string       // path to go.mod file used when loading this module, if any
-	GoVersion string       // go version used in module
-	Error     *ModuleError // error loading module
-}
-type ModuleError struct {
-	Err string // the error itself
-}
+import (
+	"golang.org/x/tools/internal/gocommand"
+)
 
 var GetForTest = func(p interface{}) string { return "" }
 
-var GetModule = func(p interface{}) *Module { return nil }
+var GetGoCmdRunner = func(config interface{}) *gocommand.Runner { return nil }
+
+var SetGoCmdRunner = func(config interface{}, runner *gocommand.Runner) {}
+
+var TypecheckCgo int

vendor/golang.org/x/tools/internal/typesinternal/types.go

@@ -0,0 +1,28 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typesinternal
+
+import (
+	"go/types"
+	"reflect"
+	"unsafe"
+)
+
+func SetUsesCgo(conf *types.Config) bool {
+	v := reflect.ValueOf(conf).Elem()
+
+	f := v.FieldByName("go115UsesCgo")
+	if !f.IsValid() {
+		f = v.FieldByName("UsesCgo")
+		if !f.IsValid() {
+			return false
+		}
+	}
+
+	addr := unsafe.Pointer(f.UnsafeAddr())
+	*(*bool)(addr) = true
+
+	return true
+}