internal/lsp/code_action.go - tools - Git at Google

 // Copyright 2018 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 lsp

 import (
 	"context"
 	"fmt"
 	"sort"
 	"strings"

 	"golang.org/x/tools/internal/event"
 	"golang.org/x/tools/internal/imports"
 	"golang.org/x/tools/internal/lsp/command"
 	"golang.org/x/tools/internal/lsp/debug/tag"
 	"golang.org/x/tools/internal/lsp/mod"
 	"golang.org/x/tools/internal/lsp/protocol"
 	"golang.org/x/tools/internal/lsp/source"
 	"golang.org/x/tools/internal/span"
 	errors "golang.org/x/xerrors"
 )

 func (s *Server) codeAction(ctx context.Context, params *protocol.CodeActionParams) ([]protocol.CodeAction, error) {
 	snapshot, fh, ok, release, err := s.beginFileRequest(ctx, params.TextDocument.URI, source.UnknownKind)
 	defer release()
 	if !ok {
 		return nil, err
 	}
 	uri := fh.URI()

 	// Determine the supported actions for this file kind.
 	supportedCodeActions, ok := snapshot.View().Options().SupportedCodeActions[fh.Kind()]
 	if !ok {
 		return nil, fmt.Errorf("no supported code actions for %v file kind", fh.Kind())
 	}

 	// The Only field of the context specifies which code actions the client wants.
 	// If Only is empty, assume that the client wants all of the non-explicit code actions.
 	var wanted map[protocol.CodeActionKind]bool

 	// Explicit Code Actions are opt-in and shouldn't be returned to the client unless
 	// requested using Only.
 	// TODO: Add other CodeLenses such as GoGenerate, RegenerateCgo, etc..
 	explicit := map[protocol.CodeActionKind]bool{
 		protocol.GoTest: true,
 	}

 	if len(params.Context.Only) == 0 {
 		wanted = supportedCodeActions
 	} else {
 		wanted = make(map[protocol.CodeActionKind]bool)
 		for _, only := range params.Context.Only {
 			wanted[only] = supportedCodeActions[only] || explicit[only]
 		}
 	}
 	if len(supportedCodeActions) == 0 {
 		return nil, nil // not an error if there are none supported
 	}
 	if len(wanted) == 0 {
 		return nil, fmt.Errorf("no supported code action to execute for %s, wanted %v", uri, params.Context.Only)
 	}

 	var codeActions []protocol.CodeAction
 	switch fh.Kind() {
 	case source.Mod:
 		if diagnostics := params.Context.Diagnostics; len(diagnostics) > 0 {
 			diags, err := mod.DiagnosticsForMod(ctx, snapshot, fh)
 			if source.IsNonFatalGoModError(err) {
 				return nil, nil
 			}
 			if err != nil {
 				return nil, err
 			}
 			quickFixes, err := codeActionsMatchingDiagnostics(ctx, snapshot, diagnostics, diags)
 			if err != nil {
 				return nil, err
 			}
 			codeActions = append(codeActions, quickFixes...)
 		}
 	case source.Go:
 		// Don't suggest fixes for generated files, since they are generally
 		// not useful and some editors may apply them automatically on save.
 		if source.IsGenerated(ctx, snapshot, uri) {
 			return nil, nil
 		}
 		diagnostics := params.Context.Diagnostics

 		// First, process any missing imports and pair them with the
 		// diagnostics they fix.
 		if wantQuickFixes := wanted[protocol.QuickFix] && len(diagnostics) > 0; wantQuickFixes || wanted[protocol.SourceOrganizeImports] {
 			importEdits, importEditsPerFix, err := source.AllImportsFixes(ctx, snapshot, fh)
 			if err != nil {
 				event.Error(ctx, "imports fixes", err, tag.File.Of(fh.URI().Filename()))
 			}
 			// Separate this into a set of codeActions per diagnostic, where
 			// each action is the addition, removal, or renaming of one import.
 			if wantQuickFixes {
 				for _, importFix := range importEditsPerFix {
 					fixes := importDiagnostics(importFix.Fix, diagnostics)
 					if len(fixes) == 0 {
 						continue
 					}
 					codeActions = append(codeActions, protocol.CodeAction{
 						Title: importFixTitle(importFix.Fix),
 						Kind:  protocol.QuickFix,
 						Edit: protocol.WorkspaceEdit{
 							DocumentChanges: documentChanges(fh, importFix.Edits),
 						},
 						Diagnostics: fixes,
 					})
 				}
 			}

 			// Send all of the import edits as one code action if the file is
 			// being organized.
 			if wanted[protocol.SourceOrganizeImports] && len(importEdits) > 0 {
 				codeActions = append(codeActions, protocol.CodeAction{
 					Title: "Organize Imports",
 					Kind:  protocol.SourceOrganizeImports,
 					Edit: protocol.WorkspaceEdit{
 						DocumentChanges: documentChanges(fh, importEdits),
 					},
 				})
 			}
 		}
 		if ctx.Err() != nil {
 			return nil, ctx.Err()
 		}
 		pkg, err := snapshot.PackageForFile(ctx, fh.URI(), source.TypecheckFull, source.WidestPackage)
 		if err != nil {
 			return nil, err
 		}

 		pkgDiagnostics, err := snapshot.DiagnosePackage(ctx, pkg)
 		if err != nil {
 			return nil, err
 		}
 		analysisDiags, err := source.Analyze(ctx, snapshot, pkg, true)
 		if err != nil {
 			return nil, err
 		}
 		fileDiags := append(pkgDiagnostics[uri], analysisDiags[uri]...)

 		// Split diagnostics into fixes, which must match incoming diagnostics,
 		// and non-fixes, which must match the requested range. Build actions
 		// for all of them.
 		var fixDiags, nonFixDiags []*source.Diagnostic
 		for _, d := range fileDiags {
 			if len(d.SuggestedFixes) == 0 {
 				continue
 			}
 			var isFix bool
 			for _, fix := range d.SuggestedFixes {
 				if fix.ActionKind == protocol.QuickFix || fix.ActionKind == protocol.SourceFixAll {
 					isFix = true
 					break
 				}
 			}
 			if isFix {
 				fixDiags = append(fixDiags, d)
 			} else {
 				nonFixDiags = append(nonFixDiags, d)
 			}
 		}

 		fixActions, err := codeActionsMatchingDiagnostics(ctx, snapshot, diagnostics, fixDiags)
 		if err != nil {
 			return nil, err
 		}
 		codeActions = append(codeActions, fixActions...)

 		for _, nonfix := range nonFixDiags {
 			// For now, only show diagnostics for matching lines. Maybe we should
 			// alter this behavior in the future, depending on the user experience.
 			if !protocol.Intersect(nonfix.Range, params.Range) {
 				continue
 			}
 			actions, err := codeActionsForDiagnostic(ctx, snapshot, nonfix, nil)
 			if err != nil {
 				return nil, err
 			}
 			codeActions = append(codeActions, actions...)
 		}

 		if wanted[protocol.RefactorExtract] {
 			fixes, err := extractionFixes(ctx, snapshot, pkg, uri, params.Range)
 			if err != nil {
 				return nil, err
 			}
 			codeActions = append(codeActions, fixes...)
 		}

 		if wanted[protocol.GoTest] {
 			fixes, err := goTest(ctx, snapshot, uri, params.Range)
 			if err != nil {
 				return nil, err
 			}
 			codeActions = append(codeActions, fixes...)
 		}

 	default:
 		// Unsupported file kind for a code action.
 		return nil, nil
 	}

 	var filtered []protocol.CodeAction
 	for _, action := range codeActions {
 		if wanted[action.Kind] {
 			filtered = append(filtered, action)
 		}
 	}
 	return filtered, nil
 }

 func (s *Server) getSupportedCodeActions() []protocol.CodeActionKind {
 	allCodeActionKinds := make(map[protocol.CodeActionKind]struct{})
 	for _, kinds := range s.session.Options().SupportedCodeActions {
 		for kind := range kinds {
 			allCodeActionKinds[kind] = struct{}{}
 		}
 	}
 	var result []protocol.CodeActionKind
 	for kind := range allCodeActionKinds {
 		result = append(result, kind)
 	}
 	sort.Slice(result, func(i, j int) bool {
 		return result[i] < result[j]
 	})
 	return result
 }

 func importFixTitle(fix *imports.ImportFix) string {
 	var str string
 	switch fix.FixType {
 	case imports.AddImport:
 		str = fmt.Sprintf("Add import: %s %q", fix.StmtInfo.Name, fix.StmtInfo.ImportPath)
 	case imports.DeleteImport:
 		str = fmt.Sprintf("Delete import: %s %q", fix.StmtInfo.Name, fix.StmtInfo.ImportPath)
 	case imports.SetImportName:
 		str = fmt.Sprintf("Rename import: %s %q", fix.StmtInfo.Name, fix.StmtInfo.ImportPath)
 	}
 	return str
 }

 func importDiagnostics(fix *imports.ImportFix, diagnostics []protocol.Diagnostic) (results []protocol.Diagnostic) {
 	for _, diagnostic := range diagnostics {
 		switch {
 		// "undeclared name: X" may be an unresolved import.
 		case strings.HasPrefix(diagnostic.Message, "undeclared name: "):
 			ident := strings.TrimPrefix(diagnostic.Message, "undeclared name: ")
 			if ident == fix.IdentName {
 				results = append(results, diagnostic)
 			}
 		// "could not import: X" may be an invalid import.
 		case strings.HasPrefix(diagnostic.Message, "could not import: "):
 			ident := strings.TrimPrefix(diagnostic.Message, "could not import: ")
 			if ident == fix.IdentName {
 				results = append(results, diagnostic)
 			}
 		// "X imported but not used" is an unused import.
 		// "X imported but not used as Y" is an unused import.
 		case strings.Contains(diagnostic.Message, " imported but not used"):
 			idx := strings.Index(diagnostic.Message, " imported but not used")
 			importPath := diagnostic.Message[:idx]
 			if importPath == fmt.Sprintf("%q", fix.StmtInfo.ImportPath) {
 				results = append(results, diagnostic)
 			}
 		}
 	}
 	return results
 }

 func extractionFixes(ctx context.Context, snapshot source.Snapshot, pkg source.Package, uri span.URI, rng protocol.Range) ([]protocol.CodeAction, error) {
 	if rng.Start == rng.End {
 		return nil, nil
 	}
 	fh, err := snapshot.GetFile(ctx, uri)
 	if err != nil {
 		return nil, err
 	}
 	_, pgf, err := source.GetParsedFile(ctx, snapshot, fh, source.NarrowestPackage)
 	if err != nil {
 		return nil, errors.Errorf("getting file for Identifier: %w", err)
 	}
 	srng, err := pgf.Mapper.RangeToSpanRange(rng)
 	if err != nil {
 		return nil, err
 	}
 	puri := protocol.URIFromSpanURI(uri)
 	var commands []protocol.Command
 	if _, ok, methodOk, _ := source.CanExtractFunction(snapshot.FileSet(), srng, pgf.Src, pgf.File); ok {
 		cmd, err := command.NewApplyFixCommand("Extract function", command.ApplyFixArgs{
 			URI:   puri,
 			Fix:   source.ExtractFunction,
 			Range: rng,
 		})
 		if err != nil {
 			return nil, err
 		}
 		commands = append(commands, cmd)
 		if methodOk {
 			cmd, err := command.NewApplyFixCommand("Extract method", command.ApplyFixArgs{
 				URI:   puri,
 				Fix:   source.ExtractMethod,
 				Range: rng,
 			})
 			if err != nil {
 				return nil, err
 			}
 			commands = append(commands, cmd)
 		}
 	}
 	if _, _, ok, _ := source.CanExtractVariable(srng, pgf.File); ok {
 		cmd, err := command.NewApplyFixCommand("Extract variable", command.ApplyFixArgs{
 			URI:   puri,
 			Fix:   source.ExtractVariable,
 			Range: rng,
 		})
 		if err != nil {
 			return nil, err
 		}
 		commands = append(commands, cmd)
 	}
 	var actions []protocol.CodeAction
 	for i := range commands {
 		actions = append(actions, protocol.CodeAction{
 			Title:   commands[i].Title,
 			Kind:    protocol.RefactorExtract,
 			Command: &commands[i],
 		})
 	}
 	return actions, nil
 }

 func documentChanges(fh source.VersionedFileHandle, edits []protocol.TextEdit) []protocol.TextDocumentEdit {
 	return []protocol.TextDocumentEdit{
 		{
 			TextDocument: protocol.OptionalVersionedTextDocumentIdentifier{
 				Version: fh.Version(),
 				TextDocumentIdentifier: protocol.TextDocumentIdentifier{
 					URI: protocol.URIFromSpanURI(fh.URI()),
 				},
 			},
 			Edits: edits,
 		},
 	}
 }

 func codeActionsMatchingDiagnostics(ctx context.Context, snapshot source.Snapshot, pdiags []protocol.Diagnostic, sdiags []*source.Diagnostic) ([]protocol.CodeAction, error) {
 	var actions []protocol.CodeAction
 	for _, sd := range sdiags {
 		var diag *protocol.Diagnostic
 		for _, pd := range pdiags {
 			if sameDiagnostic(pd, sd) {
 				diag = &pd
 				break
 			}
 		}
 		if diag == nil {
 			continue
 		}
 		diagActions, err := codeActionsForDiagnostic(ctx, snapshot, sd, diag)
 		if err != nil {
 			return nil, err
 		}
 		actions = append(actions, diagActions...)

 	}
 	return actions, nil
 }

 func codeActionsForDiagnostic(ctx context.Context, snapshot source.Snapshot, sd *source.Diagnostic, pd *protocol.Diagnostic) ([]protocol.CodeAction, error) {
 	var actions []protocol.CodeAction
 	for _, fix := range sd.SuggestedFixes {
 		var changes []protocol.TextDocumentEdit
 		for uri, edits := range fix.Edits {
 			fh, err := snapshot.GetVersionedFile(ctx, uri)
 			if err != nil {
 				return nil, err
 			}
 			changes = append(changes, protocol.TextDocumentEdit{
 				TextDocument: protocol.OptionalVersionedTextDocumentIdentifier{
 					Version: fh.Version(),
 					TextDocumentIdentifier: protocol.TextDocumentIdentifier{
 						URI: protocol.URIFromSpanURI(uri),
 					},
 				},
 				Edits: edits,
 			})
 		}
 		action := protocol.CodeAction{
 			Title: fix.Title,
 			Kind:  fix.ActionKind,
 			Edit: protocol.WorkspaceEdit{
 				DocumentChanges: changes,
 			},
 			Command: fix.Command,
 		}
 		if pd != nil {
 			action.Diagnostics = []protocol.Diagnostic{*pd}
 		}
 		actions = append(actions, action)
 	}
 	return actions, nil
 }

 func sameDiagnostic(pd protocol.Diagnostic, sd *source.Diagnostic) bool {
 	return pd.Message == sd.Message && protocol.CompareRange(pd.Range, sd.Range) == 0 && pd.Source == string(sd.Source)
 }

 func goTest(ctx context.Context, snapshot source.Snapshot, uri span.URI, rng protocol.Range) ([]protocol.CodeAction, error) {
 	fh, err := snapshot.GetFile(ctx, uri)
 	if err != nil {
 		return nil, err
 	}
 	fns, err := source.TestsAndBenchmarks(ctx, snapshot, fh)
 	if err != nil {
 		return nil, err
 	}

 	var tests, benchmarks []string
 	for _, fn := range fns.Tests {
 		if !protocol.Intersect(fn.Rng, rng) {
 			continue
 		}
 		tests = append(tests, fn.Name)
 	}
 	for _, fn := range fns.Benchmarks {
 		if !protocol.Intersect(fn.Rng, rng) {
 			continue
 		}
 		benchmarks = append(benchmarks, fn.Name)
 	}

 	if len(tests) == 0 && len(benchmarks) == 0 {
 		return nil, nil
 	}

 	cmd, err := command.NewTestCommand("Run tests and benchmarks", protocol.URIFromSpanURI(uri), tests, benchmarks)
 	if err != nil {
 		return nil, err
 	}
 	return []protocol.CodeAction{{
 		Title:   cmd.Title,
 		Kind:    protocol.GoTest,
 		Command: &cmd,
 	}}, nil
 }
	// Copyright 2018 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 lsp

	import (
	"context"
	"fmt"
	"sort"
	"strings"

	"golang.org/x/tools/internal/event"
	"golang.org/x/tools/internal/imports"
	"golang.org/x/tools/internal/lsp/command"
	"golang.org/x/tools/internal/lsp/debug/tag"
	"golang.org/x/tools/internal/lsp/mod"
	"golang.org/x/tools/internal/lsp/protocol"
	"golang.org/x/tools/internal/lsp/source"
	"golang.org/x/tools/internal/span"
	errors "golang.org/x/xerrors"
	)

	func (s Server) codeAction(ctx context.Context, params protocol.CodeActionParams) ([]protocol.CodeAction, error) {
	snapshot, fh, ok, release, err := s.beginFileRequest(ctx, params.TextDocument.URI, source.UnknownKind)
	defer release()
	if !ok {
	return nil, err
	}
	uri := fh.URI()

	// Determine the supported actions for this file kind.
	supportedCodeActions, ok := snapshot.View().Options().SupportedCodeActions[fh.Kind()]
	if !ok {
	return nil, fmt.Errorf("no supported code actions for %v file kind", fh.Kind())
	}

	// The Only field of the context specifies which code actions the client wants.
	// If Only is empty, assume that the client wants all of the non-explicit code actions.
	var wanted map[protocol.CodeActionKind]bool

	// Explicit Code Actions are opt-in and shouldn't be returned to the client unless
	// requested using Only.
	// TODO: Add other CodeLenses such as GoGenerate, RegenerateCgo, etc..
	explicit := map[protocol.CodeActionKind]bool{
	protocol.GoTest: true,
	}

	if len(params.Context.Only) == 0 {
	wanted = supportedCodeActions
	} else {
	wanted = make(map[protocol.CodeActionKind]bool)
	for _, only := range params.Context.Only {
	wanted[only] = supportedCodeActions[only] \|\| explicit[only]
	}
	}
	if len(supportedCodeActions) == 0 {
	return nil, nil // not an error if there are none supported
	}
	if len(wanted) == 0 {
	return nil, fmt.Errorf("no supported code action to execute for %s, wanted %v", uri, params.Context.Only)
	}

	var codeActions []protocol.CodeAction
	switch fh.Kind() {
	case source.Mod:
	if diagnostics := params.Context.Diagnostics; len(diagnostics) > 0 {
	diags, err := mod.DiagnosticsForMod(ctx, snapshot, fh)
	if source.IsNonFatalGoModError(err) {
	return nil, nil
	}
	if err != nil {
	return nil, err
	}
	quickFixes, err := codeActionsMatchingDiagnostics(ctx, snapshot, diagnostics, diags)
	if err != nil {
	return nil, err
	}
	codeActions = append(codeActions, quickFixes...)
	}
	case source.Go:
	// Don't suggest fixes for generated files, since they are generally
	// not useful and some editors may apply them automatically on save.
	if source.IsGenerated(ctx, snapshot, uri) {
	return nil, nil
	}
	diagnostics := params.Context.Diagnostics

	// First, process any missing imports and pair them with the
	// diagnostics they fix.
	if wantQuickFixes := wanted[protocol.QuickFix] && len(diagnostics) > 0; wantQuickFixes \|\| wanted[protocol.SourceOrganizeImports] {
	importEdits, importEditsPerFix, err := source.AllImportsFixes(ctx, snapshot, fh)
	if err != nil {
	event.Error(ctx, "imports fixes", err, tag.File.Of(fh.URI().Filename()))
	}
	// Separate this into a set of codeActions per diagnostic, where
	// each action is the addition, removal, or renaming of one import.
	if wantQuickFixes {
	for _, importFix := range importEditsPerFix {
	fixes := importDiagnostics(importFix.Fix, diagnostics)
	if len(fixes) == 0 {
	continue
	}
	codeActions = append(codeActions, protocol.CodeAction{
	Title: importFixTitle(importFix.Fix),
	Kind: protocol.QuickFix,
	Edit: protocol.WorkspaceEdit{
	DocumentChanges: documentChanges(fh, importFix.Edits),
	},
	Diagnostics: fixes,
	})
	}
	}

	// Send all of the import edits as one code action if the file is
	// being organized.
	if wanted[protocol.SourceOrganizeImports] && len(importEdits) > 0 {
	codeActions = append(codeActions, protocol.CodeAction{
	Title: "Organize Imports",
	Kind: protocol.SourceOrganizeImports,
	Edit: protocol.WorkspaceEdit{
	DocumentChanges: documentChanges(fh, importEdits),
	},
	})
	}
	}
	if ctx.Err() != nil {
	return nil, ctx.Err()
	}
	pkg, err := snapshot.PackageForFile(ctx, fh.URI(), source.TypecheckFull, source.WidestPackage)
	if err != nil {
	return nil, err
	}

	pkgDiagnostics, err := snapshot.DiagnosePackage(ctx, pkg)
	if err != nil {
	return nil, err
	}
	analysisDiags, err := source.Analyze(ctx, snapshot, pkg, true)
	if err != nil {
	return nil, err
	}
	fileDiags := append(pkgDiagnostics[uri], analysisDiags[uri]...)

	// Split diagnostics into fixes, which must match incoming diagnostics,
	// and non-fixes, which must match the requested range. Build actions
	// for all of them.
	var fixDiags, nonFixDiags []*source.Diagnostic
	for _, d := range fileDiags {
	if len(d.SuggestedFixes) == 0 {
	continue
	}
	var isFix bool
	for _, fix := range d.SuggestedFixes {
	if fix.ActionKind == protocol.QuickFix \|\| fix.ActionKind == protocol.SourceFixAll {
	isFix = true
	break
	}
	}
	if isFix {
	fixDiags = append(fixDiags, d)
	} else {
	nonFixDiags = append(nonFixDiags, d)
	}
	}

	fixActions, err := codeActionsMatchingDiagnostics(ctx, snapshot, diagnostics, fixDiags)
	if err != nil {
	return nil, err
	}
	codeActions = append(codeActions, fixActions...)

	for _, nonfix := range nonFixDiags {
	// For now, only show diagnostics for matching lines. Maybe we should
	// alter this behavior in the future, depending on the user experience.
	if !protocol.Intersect(nonfix.Range, params.Range) {
	continue
	}
	actions, err := codeActionsForDiagnostic(ctx, snapshot, nonfix, nil)
	if err != nil {
	return nil, err
	}
	codeActions = append(codeActions, actions...)
	}

	if wanted[protocol.RefactorExtract] {
	fixes, err := extractionFixes(ctx, snapshot, pkg, uri, params.Range)
	if err != nil {
	return nil, err
	}
	codeActions = append(codeActions, fixes...)
	}

	if wanted[protocol.GoTest] {
	fixes, err := goTest(ctx, snapshot, uri, params.Range)
	if err != nil {
	return nil, err
	}
	codeActions = append(codeActions, fixes...)
	}

	default:
	// Unsupported file kind for a code action.
	return nil, nil
	}

	var filtered []protocol.CodeAction
	for _, action := range codeActions {
	if wanted[action.Kind] {
	filtered = append(filtered, action)
	}
	}
	return filtered, nil
	}

	func (s *Server) getSupportedCodeActions() []protocol.CodeActionKind {
	allCodeActionKinds := make(map[protocol.CodeActionKind]struct{})
	for _, kinds := range s.session.Options().SupportedCodeActions {
	for kind := range kinds {
	allCodeActionKinds[kind] = struct{}{}
	}
	}
	var result []protocol.CodeActionKind
	for kind := range allCodeActionKinds {
	result = append(result, kind)
	}
	sort.Slice(result, func(i, j int) bool {
	return result[i] < result[j]
	})
	return result
	}

	func importFixTitle(fix *imports.ImportFix) string {
	var str string
	switch fix.FixType {
	case imports.AddImport:
	str = fmt.Sprintf("Add import: %s %q", fix.StmtInfo.Name, fix.StmtInfo.ImportPath)
	case imports.DeleteImport:
	str = fmt.Sprintf("Delete import: %s %q", fix.StmtInfo.Name, fix.StmtInfo.ImportPath)
	case imports.SetImportName:
	str = fmt.Sprintf("Rename import: %s %q", fix.StmtInfo.Name, fix.StmtInfo.ImportPath)
	}
	return str
	}

	func importDiagnostics(fix *imports.ImportFix, diagnostics []protocol.Diagnostic) (results []protocol.Diagnostic) {
	for _, diagnostic := range diagnostics {
	switch {
	// "undeclared name: X" may be an unresolved import.
	case strings.HasPrefix(diagnostic.Message, "undeclared name: "):
	ident := strings.TrimPrefix(diagnostic.Message, "undeclared name: ")
	if ident == fix.IdentName {
	results = append(results, diagnostic)
	}
	// "could not import: X" may be an invalid import.
	case strings.HasPrefix(diagnostic.Message, "could not import: "):
	ident := strings.TrimPrefix(diagnostic.Message, "could not import: ")
	if ident == fix.IdentName {
	results = append(results, diagnostic)
	}
	// "X imported but not used" is an unused import.
	// "X imported but not used as Y" is an unused import.
	case strings.Contains(diagnostic.Message, " imported but not used"):
	idx := strings.Index(diagnostic.Message, " imported but not used")
	importPath := diagnostic.Message[:idx]
	if importPath == fmt.Sprintf("%q", fix.StmtInfo.ImportPath) {
	results = append(results, diagnostic)
	}
	}
	}
	return results
	}

	func extractionFixes(ctx context.Context, snapshot source.Snapshot, pkg source.Package, uri span.URI, rng protocol.Range) ([]protocol.CodeAction, error) {
	if rng.Start == rng.End {
	return nil, nil
	}
	fh, err := snapshot.GetFile(ctx, uri)
	if err != nil {
	return nil, err
	}
	_, pgf, err := source.GetParsedFile(ctx, snapshot, fh, source.NarrowestPackage)
	if err != nil {
	return nil, errors.Errorf("getting file for Identifier: %w", err)
	}
	srng, err := pgf.Mapper.RangeToSpanRange(rng)
	if err != nil {
	return nil, err
	}
	puri := protocol.URIFromSpanURI(uri)
	var commands []protocol.Command
	if _, ok, methodOk, _ := source.CanExtractFunction(snapshot.FileSet(), srng, pgf.Src, pgf.File); ok {
	cmd, err := command.NewApplyFixCommand("Extract function", command.ApplyFixArgs{
	URI: puri,
	Fix: source.ExtractFunction,
	Range: rng,
	})
	if err != nil {
	return nil, err
	}
	commands = append(commands, cmd)
	if methodOk {
	cmd, err := command.NewApplyFixCommand("Extract method", command.ApplyFixArgs{
	URI: puri,
	Fix: source.ExtractMethod,
	Range: rng,
	})
	if err != nil {
	return nil, err
	}
	commands = append(commands, cmd)
	}
	}
	if _, _, ok, _ := source.CanExtractVariable(srng, pgf.File); ok {
	cmd, err := command.NewApplyFixCommand("Extract variable", command.ApplyFixArgs{
	URI: puri,
	Fix: source.ExtractVariable,
	Range: rng,
	})
	if err != nil {
	return nil, err
	}
	commands = append(commands, cmd)
	}
	var actions []protocol.CodeAction
	for i := range commands {
	actions = append(actions, protocol.CodeAction{
	Title: commands[i].Title,
	Kind: protocol.RefactorExtract,
	Command: &commands[i],
	})
	}
	return actions, nil
	}

	func documentChanges(fh source.VersionedFileHandle, edits []protocol.TextEdit) []protocol.TextDocumentEdit {
	return []protocol.TextDocumentEdit{
	{
	TextDocument: protocol.OptionalVersionedTextDocumentIdentifier{
	Version: fh.Version(),
	TextDocumentIdentifier: protocol.TextDocumentIdentifier{
	URI: protocol.URIFromSpanURI(fh.URI()),
	},
	},
	Edits: edits,
	},
	}
	}

	func codeActionsMatchingDiagnostics(ctx context.Context, snapshot source.Snapshot, pdiags []protocol.Diagnostic, sdiags []*source.Diagnostic) ([]protocol.CodeAction, error) {
	var actions []protocol.CodeAction
	for _, sd := range sdiags {
	var diag *protocol.Diagnostic
	for _, pd := range pdiags {
	if sameDiagnostic(pd, sd) {
	diag = &pd
	break
	}
	}
	if diag == nil {
	continue
	}
	diagActions, err := codeActionsForDiagnostic(ctx, snapshot, sd, diag)
	if err != nil {
	return nil, err
	}
	actions = append(actions, diagActions...)

	}
	return actions, nil
	}

	func codeActionsForDiagnostic(ctx context.Context, snapshot source.Snapshot, sd source.Diagnostic, pd protocol.Diagnostic) ([]protocol.CodeAction, error) {
	var actions []protocol.CodeAction
	for _, fix := range sd.SuggestedFixes {
	var changes []protocol.TextDocumentEdit
	for uri, edits := range fix.Edits {
	fh, err := snapshot.GetVersionedFile(ctx, uri)
	if err != nil {
	return nil, err
	}
	changes = append(changes, protocol.TextDocumentEdit{
	TextDocument: protocol.OptionalVersionedTextDocumentIdentifier{
	Version: fh.Version(),
	TextDocumentIdentifier: protocol.TextDocumentIdentifier{
	URI: protocol.URIFromSpanURI(uri),
	},
	},
	Edits: edits,
	})
	}
	action := protocol.CodeAction{
	Title: fix.Title,
	Kind: fix.ActionKind,
	Edit: protocol.WorkspaceEdit{
	DocumentChanges: changes,
	},
	Command: fix.Command,
	}
	if pd != nil {
	action.Diagnostics = []protocol.Diagnostic{*pd}
	}
	actions = append(actions, action)
	}
	return actions, nil
	}

	func sameDiagnostic(pd protocol.Diagnostic, sd *source.Diagnostic) bool {
	return pd.Message == sd.Message && protocol.CompareRange(pd.Range, sd.Range) == 0 && pd.Source == string(sd.Source)
	}

	func goTest(ctx context.Context, snapshot source.Snapshot, uri span.URI, rng protocol.Range) ([]protocol.CodeAction, error) {
	fh, err := snapshot.GetFile(ctx, uri)
	if err != nil {
	return nil, err
	}
	fns, err := source.TestsAndBenchmarks(ctx, snapshot, fh)
	if err != nil {
	return nil, err
	}

	var tests, benchmarks []string
	for _, fn := range fns.Tests {
	if !protocol.Intersect(fn.Rng, rng) {
	continue
	}
	tests = append(tests, fn.Name)
	}
	for _, fn := range fns.Benchmarks {
	if !protocol.Intersect(fn.Rng, rng) {
	continue
	}
	benchmarks = append(benchmarks, fn.Name)
	}

	if len(tests) == 0 && len(benchmarks) == 0 {
	return nil, nil
	}

	cmd, err := command.NewTestCommand("Run tests and benchmarks", protocol.URIFromSpanURI(uri), tests, benchmarks)
	if err != nil {
	return nil, err
	}
	return []protocol.CodeAction{{
	Title: cmd.Title,
	Kind: protocol.GoTest,
	Command: &cmd,
	}}, nil
	}