internal/lsp: stop caching diagnostics on the package

Now that we are using the memoize package to cache analysis results, we
can use that cache for suggested fixes.

Change-Id: I42905a6fe575f49d38979d53d58ea8ec59210ae0
Reviewed-on: https://go-review.googlesource.com/c/tools/+/203278
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>

internal/lsp/cache/analysis.go

@@ -123,7 +123,7 @@ func (s *snapshot) actionHandle(ctx context.Context, id packageID, mode source.P
 	}
 	h := s.view.session.cache.store.Bind(buildActionKey(a, cph), func(ctx context.Context) interface{} {
 		data := &actionData{}
-		data.diagnostics, data.result, data.err = ah.exec(ctx, s.view.session.cache.fset)
+		data.diagnostics, data.result, data.err = run(ctx, s.view.session.cache.fset, ah)
 		return data
 	})
 	ah.handle = h
@@ -141,6 +141,15 @@ func (act *actionHandle) analyze(ctx context.Context) ([]*source.Error, interfac
 	return data.diagnostics, data.result, data.err
 }
 
+func (act *actionHandle) cached() ([]*source.Error, interface{}, error) {
+	v := act.handle.Cached()
+	if v == nil {
+		return nil, nil, errors.Errorf("no analyses for %s", act.pkg.ID())
+	}
+	data := v.(*actionData)
+	return data.diagnostics, data.result, data.err
+}
+
 func buildActionKey(a *analysis.Analyzer, cph *checkPackageHandle) string {
 	return hashContents([]byte(fmt.Sprintf("%p %s", a, string(cph.key))))
 }
@@ -177,7 +186,7 @@ func execAll(ctx context.Context, fset *token.FileSet, actions []*actionHandle)
 	return diagnostics, results, g.Wait()
 }
 
-func (act *actionHandle) exec(ctx context.Context, fset *token.FileSet) ([]*source.Error, interface{}, error) {
+func run(ctx context.Context, fset *token.FileSet, act *actionHandle) ([]*source.Error, interface{}, error) {
 	// Analyze dependencies.
 	_, depResults, err := execAll(ctx, fset, act.deps)
 	if err != nil {
@@ -209,12 +218,20 @@ func (act *actionHandle) exec(ctx context.Context, fset *token.FileSet) ([]*sour
 	pass := &analysis.Pass{
 		Analyzer:   act.analyzer,
 		Fset:       fset,
-		Files:             act.pkg.GetSyntax(ctx),
+		Files:      act.pkg.GetSyntax(),
 		Pkg:        act.pkg.GetTypes(),
 		TypesInfo:  act.pkg.GetTypesInfo(),
 		TypesSizes: act.pkg.GetTypesSizes(),
 		ResultOf:   inputs,
-		Report:            func(d analysis.Diagnostic) { diagnostics = append(diagnostics, &d) },
+		Report: func(d analysis.Diagnostic) {
+			// Prefix the diagnostic category with the analyzer's name.
+			if d.Category == "" {
+				d.Category = act.analyzer.Name
+			} else {
+				d.Category = act.analyzer.Name + "." + d.Category
+			}
+			diagnostics = append(diagnostics, &d)
+		},
 		ImportObjectFact:  act.importObjectFact,
 		ExportObjectFact:  act.exportObjectFact,
 		ImportPackageFact: act.importPackageFact,

internal/lsp/cache/check.go

@@ -202,11 +202,11 @@ func (cph *checkPackageHandle) MissingDependencies() []string {
 	return md
 }
 
-func (cph *checkPackageHandle) Cached(ctx context.Context) (source.Package, error) {
+func (cph *checkPackageHandle) Cached() (source.Package, error) {
-	return cph.cached(ctx)
+	return cph.cached()
 }
 
-func (cph *checkPackageHandle) cached(ctx context.Context) (*pkg, error) {
+func (cph *checkPackageHandle) cached() (*pkg, error) {
 	v := cph.handle.Cached()
 	if v == nil {
 		return nil, errors.Errorf("no cached type information for %s", cph.m.pkgPath)

internal/lsp/cache/errors.go

@@ -167,7 +167,7 @@ func typeErrorRange(ctx context.Context, fset *token.FileSet, pkg *pkg, pos toke
 	if err != nil {
 		return spn, nil // ignore errors
 	}
-	file, m, _, err := ph.Cached(ctx)
+	file, m, _, err := ph.Cached()
 	if err != nil {
 		return spn, nil
 	}
@@ -200,7 +200,7 @@ func scannerErrorRange(ctx context.Context, fset *token.FileSet, pkg *pkg, posn
 	if err != nil {
 		return span.Span{}, err
 	}
-	file, _, _, err := ph.Cached(ctx)
+	file, _, _, err := ph.Cached()
 	if err != nil {
 		return span.Span{}, err
 	}
@@ -228,7 +228,7 @@ func spanToRange(ctx context.Context, pkg *pkg, spn span.Span) (protocol.Range,
 	if err != nil {
 		return protocol.Range{}, err
 	}
-	_, m, _, err := ph.Cached(ctx)
+	_, m, _, err := ph.Cached()
 	if err != nil {
 		return protocol.Range{}, err
 	}

internal/lsp/cache/gofile.go

@@ -17,7 +17,7 @@ func (v *view) CheckPackageHandles(ctx context.Context, f source.File) (source.S
 	// Get the snapshot that will be used for type-checking.
 	s := v.getSnapshot()
 
-	cphs, err := s.checkPackageHandles(ctx, f)
+	cphs, err := s.CheckPackageHandles(ctx, f)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -27,7 +27,7 @@ func (v *view) CheckPackageHandles(ctx context.Context, f source.File) (source.S
 	return s, cphs, nil
 }
 
-func (s *snapshot) checkPackageHandles(ctx context.Context, f source.File) ([]source.CheckPackageHandle, error) {
+func (s *snapshot) CheckPackageHandles(ctx context.Context, f source.File) ([]source.CheckPackageHandle, error) {
 	ctx = telemetry.File.With(ctx, f.URI())
 
 	fh := s.Handle(ctx, f)
@@ -65,6 +65,9 @@ func (s *snapshot) checkPackageHandles(ctx context.Context, f source.File) ([]so
 		}
 		cphs = results
 	}
+	if len(cphs) == 0 {
+		return nil, errors.Errorf("no CheckPackageHandles for %s", f.URI())
+	}
 	return cphs, nil
 }
 
@@ -106,7 +109,7 @@ func (v *view) GetActiveReverseDeps(ctx context.Context, f source.File) (results
 		if _, ok := seen[f.URI()]; ok {
 			continue
 		}
-		cphs, err := s.checkPackageHandles(ctx, f)
+		cphs, err := s.CheckPackageHandles(ctx, f)
 		if err != nil {
 			continue
 		}

internal/lsp/cache/parse.go

@@ -81,7 +81,7 @@ func (h *parseGoHandle) Parse(ctx context.Context) (*ast.File, *protocol.ColumnM
 	return data.ast, data.mapper, data.parseError, data.err
 }
 
-func (h *parseGoHandle) Cached(ctx context.Context) (*ast.File, *protocol.ColumnMapper, error, error) {
+func (h *parseGoHandle) Cached() (*ast.File, *protocol.ColumnMapper, error, error) {
 	v := h.handle.Cached()
 	if v == nil {
 		return nil, nil, nil, errors.Errorf("no cached AST for %s", h.file.Identity().URI)

internal/lsp/cache/pkg.go

@@ -8,9 +8,7 @@ import (
 	"context"
 	"go/ast"
 	"go/types"
-	"sync"
 
-	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/internal/lsp/protocol"
 	"golang.org/x/tools/internal/lsp/source"
 	"golang.org/x/tools/internal/span"
@@ -32,9 +30,6 @@ type pkg struct {
 	types      *types.Package
 	typesInfo  *types.Info
 	typesSizes types.Sizes
-
-	diagMu      sync.Mutex
-	diagnostics map[*analysis.Analyzer][]source.Diagnostic
 }
 
 // Declare explicit types for package paths and IDs to ensure that we never use
@@ -68,10 +63,10 @@ func (p *pkg) File(uri span.URI) (source.ParseGoHandle, error) {
 	return nil, errors.Errorf("no ParseGoHandle for %s", uri)
 }
 
-func (p *pkg) GetSyntax(ctx context.Context) []*ast.File {
+func (p *pkg) GetSyntax() []*ast.File {
 	var syntax []*ast.File
 	for _, ph := range p.files {
-		file, _, _, err := ph.Cached(ctx)
+		file, _, _, err := ph.Cached()
 		if err == nil {
 			syntax = append(syntax, file)
 		}
@@ -107,34 +102,27 @@ func (p *pkg) GetImport(ctx context.Context, pkgPath string) (source.Package, er
 	return nil, errors.Errorf("no imported package for %s", pkgPath)
 }
 
-func (p *pkg) SetDiagnostics(a *analysis.Analyzer, diags []source.Diagnostic) {
+func (s *snapshot) FindAnalysisError(ctx context.Context, id string, diag protocol.Diagnostic) (*source.Error, error) {
-	p.diagMu.Lock()
+	acts := s.getActionHandles(packageID(id), source.ParseFull)
-	defer p.diagMu.Unlock()
+	for _, act := range acts {
-	if p.diagnostics == nil {
+		errors, _, err := act.analyze(ctx)
-		p.diagnostics = make(map[*analysis.Analyzer][]source.Diagnostic)
+		if err != nil {
+			return nil, err
 		}
-	p.diagnostics[a] = diags
+		for _, err := range errors {
-}
+			if err.Category != diag.Source {
-
-func (p *pkg) FindDiagnostic(pdiag protocol.Diagnostic) (*source.Diagnostic, error) {
-	p.diagMu.Lock()
-	defer p.diagMu.Unlock()
-
-	for a, diagnostics := range p.diagnostics {
-		if a.Name != pdiag.Source {
 				continue
 			}
-		for _, d := range diagnostics {
+			if err.Message != diag.Message {
-			if d.Message != pdiag.Message {
 				continue
 			}
-			if protocol.CompareRange(d.Range, pdiag.Range) != 0 {
+			if protocol.CompareRange(err.Range, diag.Range) != 0 {
 				continue
 			}
-			return &d, nil
+			return err, nil
 		}
 	}
-	return nil, errors.Errorf("no matching diagnostic for %v", pdiag)
+	return nil, errors.Errorf("no matching diagnostic for %v", diag)
 }
 
 func (p *pkg) FindFile(ctx context.Context, uri span.URI) (source.ParseGoHandle, source.Package, error) {

internal/lsp/cache/snapshot.go

@@ -109,6 +109,19 @@ func (s *snapshot) getPackage(id packageID, m source.ParseMode) *checkPackageHan
 	return s.packages[key]
 }
 
+func (s *snapshot) getActionHandles(id packageID, m source.ParseMode) []*actionHandle {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	var acts []*actionHandle
+	for k, v := range s.actions {
+		if k.pkg.id == id && k.pkg.mode == m {
+			acts = append(acts, v)
+		}
+	}
+	return acts
+}
+
 func (s *snapshot) getAction(id packageID, m source.ParseMode, a *analysis.Analyzer) *actionHandle {
 	s.mu.Lock()
 	defer s.mu.Unlock()

internal/lsp/code_action.go

@@ -27,7 +27,8 @@ func (s *Server) codeAction(ctx context.Context, params *protocol.CodeActionPara
 		return nil, err
 	}
 
-	fh := view.Snapshot().Handle(ctx, f)
+	snapshot := view.Snapshot()
+	fh := snapshot.Handle(ctx, f)
 
 	// Determine the supported actions for this file kind.
 	fileKind := fh.Identity().Kind
@@ -75,7 +76,7 @@ func (s *Server) codeAction(ctx context.Context, params *protocol.CodeActionPara
 		}
 		if diagnostics := params.Context.Diagnostics; wanted[protocol.QuickFix] && len(diagnostics) > 0 {
 			// First, add the quick fixes reported by go/analysis.
-			qf, err := quickFixes(ctx, view, f, diagnostics)
+			qf, err := quickFixes(ctx, snapshot, f, diagnostics)
 			if err != nil {
 				log.Error(ctx, "quick fixes failed", err, telemetry.File.Of(uri))
 			}
@@ -205,9 +206,9 @@ func importDiagnostics(fix *imports.ImportFix, diagnostics []protocol.Diagnostic
 	return results
 }
 
-func quickFixes(ctx context.Context, view source.View, f source.File, diagnostics []protocol.Diagnostic) ([]protocol.CodeAction, error) {
+func quickFixes(ctx context.Context, s source.Snapshot, f source.File, diagnostics []protocol.Diagnostic) ([]protocol.CodeAction, error) {
 	var codeActions []protocol.CodeAction
-	_, cphs, err := view.CheckPackageHandles(ctx, f)
+	cphs, err := s.CheckPackageHandles(ctx, f)
 	if err != nil {
 		return nil, err
 	}
@@ -217,16 +218,12 @@ func quickFixes(ctx context.Context, view source.View, f source.File, diagnostic
 	if err != nil {
 		return nil, err
 	}
-	pkg, err := cph.Cached(ctx)
-	if err != nil {
-		return nil, err
-	}
 	for _, diag := range diagnostics {
-		sdiag, err := pkg.FindDiagnostic(diag)
+		srcErr, err := s.FindAnalysisError(ctx, cph.ID(), diag)
 		if err != nil {
 			continue
 		}
-		for _, fix := range sdiag.SuggestedFixes {
+		for _, fix := range srcErr.SuggestedFixes {
 			edits := make(map[string][]protocol.TextEdit)
 			for uri, e := range fix.Edits {
 				edits[protocol.NewURI(uri)] = e

internal/lsp/source/completion.go

@@ -416,7 +416,7 @@ func Completion(ctx context.Context, view View, f File, pos protocol.Position, o
 	if err != nil {
 		return nil, nil, err
 	}
-	file, m, _, err := ph.Cached(ctx)
+	file, m, _, err := ph.Cached()
 	if err != nil {
 		return nil, nil, err
 	}

internal/lsp/source/completion_format.go

@@ -129,7 +129,7 @@ func (c *completer) item(cand candidate) (CompletionItem, error) {
 	if err != nil {
 		return CompletionItem{}, err
 	}
-	file, _, _, err := ph.Cached(c.ctx)
+	file, _, _, err := ph.Cached()
 	if err != nil {
 		return CompletionItem{}, err
 	}

internal/lsp/source/diagnostics.go

@@ -171,22 +171,27 @@ func analyses(ctx context.Context, snapshot Snapshot, cph CheckPackageHandle, di
 		return err
 	}
 
-	// For caching diagnostics.
-	// TODO(https://golang.org/issue/32443): Cache diagnostics on the snapshot.
-	pkg, err := cph.Check(ctx)
-	if err != nil {
-		return err
-	}
-
 	// Report diagnostics and errors from root analyzers.
-	var sdiags []Diagnostic
+	for _, diags := range diagnostics {
-	for a, diags := range diagnostics {
+		for _, e := range diags {
-		for _, diag := range diags {
+			// This is a bit of a hack, but clients > 3.15 will be able to grey out unnecessary code.
-			sdiag := toDiagnostic(diag, a.Name)
+			// If we are deleting code as part of all of our suggested fixes, assume that this is dead code.
-			addReport(snapshot.View(), reports, sdiag)
+			// TODO(golang/go/#34508): Return these codes from the diagnostics themselves.
-			sdiags = append(sdiags, sdiag)
+			var tags []protocol.DiagnosticTag
+			if onlyDeletions(e.SuggestedFixes) {
+				tags = append(tags, protocol.Unnecessary)
+			}
+			addReport(snapshot.View(), reports, Diagnostic{
+				URI:            e.URI,
+				Range:          e.Range,
+				Message:        e.Message,
+				Source:         e.Category,
+				Severity:       protocol.SeverityWarning,
+				Tags:           tags,
+				SuggestedFixes: e.SuggestedFixes,
+				Related:        e.Related,
+			})
 		}
-		pkg.SetDiagnostics(a, sdiags)
 	}
 	return nil
 }
@@ -219,29 +224,6 @@ func singleDiagnostic(uri span.URI, format string, a ...interface{}) map[span.UR
 	}
 }
 
-func toDiagnostic(e *Error, category string) Diagnostic {
-	// This is a bit of a hack, but clients > 3.15 will be able to grey out unnecessary code.
-	// If we are deleting code as part of all of our suggested fixes, assume that this is dead code.
-	// TODO(golang/go/#34508): Return these codes from the diagnostics themselves.
-	var tags []protocol.DiagnosticTag
-	if onlyDeletions(e.SuggestedFixes) {
-		tags = append(tags, protocol.Unnecessary)
-	}
-	if e.Category != "" {
-		category += "." + e.Category
-	}
-	return Diagnostic{
-		URI:            e.URI,
-		Range:          e.Range,
-		Message:        e.Message,
-		Source:         category,
-		Severity:       protocol.SeverityWarning,
-		Tags:           tags,
-		SuggestedFixes: e.SuggestedFixes,
-		Related:        e.Related,
-	}
-}
-
 // onlyDeletions returns true if all of the suggested fixes are deletions.
 func onlyDeletions(fixes []SuggestedFix) bool {
 	for _, fix := range fixes {

internal/lsp/source/identifier.go

@@ -64,7 +64,7 @@ func Identifier(ctx context.Context, view View, f File, pos protocol.Position) (
 	if err != nil {
 		return nil, err
 	}
-	file, m, _, err := ph.Cached(ctx)
+	file, m, _, err := ph.Cached()
 	if err != nil {
 		return nil, err
 	}
@@ -248,7 +248,7 @@ func objToNode(ctx context.Context, pkg Package, obj types.Object) (ast.Decl, er
 	if err != nil {
 		return nil, err
 	}
-	declAST, _, _, err := ph.Cached(ctx)
+	declAST, _, _, err := ph.Cached()
 	if declAST == nil {
 		return nil, err
 	}
@@ -313,12 +313,12 @@ func importSpec(ctx context.Context, snapshot Snapshot, pkg Package, file *ast.F
 	if err != nil {
 		return nil, err
 	}
-	if importedPkg.GetSyntax(ctx) == nil {
+	if importedPkg.GetSyntax() == nil {
 		return nil, errors.Errorf("no syntax for for %q", importPath)
 	}
 	// Heuristic: Jump to the longest (most "interesting") file of the package.
 	var dest *ast.File
-	for _, f := range importedPkg.GetSyntax(ctx) {
+	for _, f := range importedPkg.GetSyntax() {
 		if dest == nil || f.End()-f.Pos() > dest.End()-dest.Pos() {
 			dest = f
 		}

internal/lsp/source/rename.go

@@ -180,7 +180,7 @@ func (i *IdentifierInfo) getPkgName(ctx context.Context) (*IdentifierInfo, error
 	if err != nil {
 		return nil, err
 	}
-	file, _, _, err := ph.Cached(ctx)
+	file, _, _, err := ph.Cached()
 	if err != nil {
 		return nil, err
 	}

internal/lsp/source/rename_check.go

@@ -117,7 +117,7 @@ func (r *renamer) checkInPackageBlock(from types.Object) {
 	}
 
 	// Check for conflicts between package block and all file blocks.
-	for _, f := range pkg.GetSyntax(r.ctx) {
+	for _, f := range pkg.GetSyntax() {
 		fileScope := pkg.GetTypesInfo().Scopes[f]
 		b, prev := fileScope.LookupParent(r.to, token.NoPos)
 		if b == fileScope {
@@ -331,7 +331,7 @@ func forEachLexicalRef(ctx context.Context, pkg Package, obj types.Object, fn fu
 		return true
 	}
 
-	for _, f := range pkg.GetSyntax(ctx) {
+	for _, f := range pkg.GetSyntax() {
 		ast.Inspect(f, visit)
 		if len(stack) != 0 {
 			panic(stack)
@@ -808,7 +808,7 @@ func (r *renamer) satisfy() map[satisfy.Constraint]bool {
 					r.from, r.to, pkg.PkgPath())
 				return nil
 			}
-			f.Find(pkg.GetTypesInfo(), pkg.GetSyntax(r.ctx))
+			f.Find(pkg.GetTypesInfo(), pkg.GetSyntax())
 		}
 		r.satisfyConstraints = f.Result
 	}
@@ -841,7 +841,7 @@ func someUse(info *types.Info, obj types.Object) *ast.Ident {
 //
 func pathEnclosingInterval(ctx context.Context, fset *token.FileSet, pkg Package, start, end token.Pos) (resPkg Package, path []ast.Node, exact bool) {
 	var pkgs = []Package{pkg}
-	for _, f := range pkg.GetSyntax(ctx) {
+	for _, f := range pkg.GetSyntax() {
 		for _, imp := range f.Imports {
 			if imp == nil {
 				continue
@@ -858,7 +858,7 @@ func pathEnclosingInterval(ctx context.Context, fset *token.FileSet, pkg Package
 		}
 	}
 	for _, p := range pkgs {
-		for _, f := range p.GetSyntax(ctx) {
+		for _, f := range p.GetSyntax() {
 			if f.Pos() == token.NoPos {
 				// This can happen if the parser saw
 				// too many errors and bailed out.

internal/lsp/source/signature_help.go

@@ -47,7 +47,7 @@ func SignatureHelp(ctx context.Context, view View, f File, pos protocol.Position
 	if err != nil {
 		return nil, err
 	}
-	file, m, _, err := ph.Cached(ctx)
+	file, m, _, err := ph.Cached()
 	if err != nil {
 		return nil, err
 	}

internal/lsp/source/symbols.go

@@ -34,7 +34,7 @@ func DocumentSymbols(ctx context.Context, view View, f File) ([]protocol.Documen
 	if err != nil {
 		return nil, err
 	}
-	file, m, _, err := ph.Cached(ctx)
+	file, m, _, err := ph.Cached()
 	if err != nil {
 		return nil, err
 	}

internal/lsp/source/util.go

@@ -181,7 +181,7 @@ func posToMapper(ctx context.Context, pkg Package, pos token.Pos) (*protocol.Col
 	if err != nil {
 		return nil, err
 	}
-	_, m, _, err := ph.Cached(ctx)
+	_, m, _, err := ph.Cached()
 	return m, err
 }
 

internal/lsp/source/view.go

@@ -73,7 +73,7 @@ type ParseGoHandle interface {
 	Parse(ctx context.Context) (*ast.File, *protocol.ColumnMapper, error, error)
 
 	// Cached returns the AST for this handle, if it has already been stored.
-	Cached(ctx context.Context) (*ast.File, *protocol.ColumnMapper, error, error)
+	Cached() (*ast.File, *protocol.ColumnMapper, error, error)
 }
 
 // ParseMode controls the content of the AST produced when parsing a source file.
@@ -109,7 +109,7 @@ type CheckPackageHandle interface {
 	Check(ctx context.Context) (Package, error)
 
 	// Cached returns the Package for the CheckPackageHandle if it has already been stored.
-	Cached(ctx context.Context) (Package, error)
+	Cached() (Package, error)
 
 	// MissingDependencies reports any unresolved imports.
 	MissingDependencies() []string
@@ -263,6 +263,14 @@ type Snapshot interface {
 
 	// Analyze runs the analyses for the given package at this snapshot.
 	Analyze(ctx context.Context, id string, analyzers []*analysis.Analyzer) (map[*analysis.Analyzer][]*Error, error)
+
+	// FindAnalysisError returns the analysis error represented by the diagnostic.
+	// This is used to get the SuggestedFixes associated with that error.
+	FindAnalysisError(ctx context.Context, id string, diag protocol.Diagnostic) (*Error, error)
+
+	// CheckPackageHandles returns the CheckPackageHandles for the packages
+	// that this file belongs to.
+	CheckPackageHandles(ctx context.Context, f File) ([]CheckPackageHandle, error)
 }
 
 // File represents a source file of any type.
@@ -278,16 +286,13 @@ type Package interface {
 	PkgPath() string
 	Files() []ParseGoHandle
 	File(uri span.URI) (ParseGoHandle, error)
-	GetSyntax(context.Context) []*ast.File
+	GetSyntax() []*ast.File
 	GetErrors() []*Error
 	GetTypes() *types.Package
 	GetTypesInfo() *types.Info
 	GetTypesSizes() types.Sizes
 	IsIllTyped() bool
 
-	SetDiagnostics(*analysis.Analyzer, []Diagnostic)
-	FindDiagnostic(protocol.Diagnostic) (*Diagnostic, error)
-
 	// GetImport returns the CheckPackageHandle for a package imported by this package.
 	GetImport(ctx context.Context, pkgPath string) (Package, error)
 
@@ -303,7 +308,7 @@ type Error struct {
 	Range          protocol.Range
 	Kind           ErrorKind
 	Message        string
-	Category       string
+	Category       string // only used by analysis errors so far
 	SuggestedFixes []SuggestedFix
 	Related        []RelatedInformation
 }