LSP: Jump to the function name

internal/ls/definition.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/microsoft/typescript-go/internal/ast"
 	"github.com/microsoft/typescript-go/internal/astnav"
+	"github.com/microsoft/typescript-go/internal/checker"
 	"github.com/microsoft/typescript-go/internal/core"
 	"github.com/microsoft/typescript-go/internal/lsp/lsproto"
 	"github.com/microsoft/typescript-go/internal/scanner"
@@ -20,24 +21,69 @@ func (l *LanguageService) ProvideDefinition(ctx context.Context, documentURI lsp
 	checker, done := program.GetTypeCheckerForFile(ctx, file)
 	defer done()
 
+	calledDeclaration := tryGetSignatureDeclaration(checker, node)
+	if calledDeclaration != nil {
+		name := ast.GetNameOfDeclaration(calledDeclaration)
+		if name != nil {
+			return l.createLocationsFromDeclarations([]*ast.Node{name})
+		}
+	}
+
 	if symbol := checker.GetSymbolAtLocation(node); symbol != nil {
 		if symbol.Flags&ast.SymbolFlagsAlias != 0 {
 			if resolved, ok := checker.ResolveAlias(symbol); ok {
 				symbol = resolved
 			}
 		}
 
-		locations := make([]lsproto.Location, 0, len(symbol.Declarations))
-		for _, decl := range symbol.Declarations {
-			file := ast.GetSourceFileOfNode(decl)
-			loc := decl.Loc
-			pos := scanner.GetTokenPosOfNode(decl, file, false /*includeJSDoc*/)
-			locations = append(locations, lsproto.Location{
-				Uri:   FileNameToDocumentURI(file.FileName()),
-				Range: l.converters.ToLSPRange(file, core.NewTextRange(pos, loc.End())),
-			})
-		}
-		return &lsproto.Definition{Locations: &locations}, nil
+		return l.createLocationsFromDeclarations(symbol.Declarations)
 	}
 	return nil, nil
 }
+
+func (l *LanguageService) createLocationsFromDeclarations(declarations []*ast.Node) (*lsproto.Definition, error) {
+	locations := make([]lsproto.Location, 0, len(declarations))
+	for _, decl := range declarations {
+		file := ast.GetSourceFileOfNode(decl)
+		loc := decl.Loc
+		pos := scanner.GetTokenPosOfNode(decl, file, false /*includeJSDoc*/)
+		locations = append(locations, lsproto.Location{
+			Uri:   FileNameToDocumentURI(file.FileName()),
+			Range: l.converters.ToLSPRange(file, core.NewTextRange(pos, loc.End())),
+		})
+	}
+	return &lsproto.Definition{Locations: &locations}, nil
+}
+
+/** Returns a CallLikeExpression where `node` is the target being invoked. */
+func getAncestorCallLikeExpression(node *ast.Node) *ast.Node {
+	target := ast.FindAncestor(node, func(n *ast.Node) bool {
+		return !isRightSideOfPropertyAccess(n)
+	})
+
+	callLike := target.Parent
+	if callLike != nil && ast.IsCallLikeExpression(callLike) && ast.GetInvokedExpression(callLike) == target {
+		return callLike
+	}
+
+	return nil
+}
+
+func tryGetSignatureDeclaration(typeChecker *checker.Checker, node *ast.Node) *ast.Node {
+	var signature *checker.Signature
+	callLike := getAncestorCallLikeExpression(node)
+	if callLike != nil {
+		signature = typeChecker.GetResolvedSignature(callLike)
+	}
+
+	// Don't go to a function type, go to the value having that type.
+	var declaration *ast.Node
+	if signature != nil && signature.Declaration() != nil {
+		declaration = signature.Declaration()
+		if ast.IsFunctionLike(declaration) && !ast.IsFunctionTypeNode(declaration) {
+			return declaration
+		}
+	}
+
+	return nil
+}

internal/ls/definition_test.go

@@ -0,0 +1,74 @@
+package ls_test
+
+import (
+	"testing"
+
+	"github.com/microsoft/typescript-go/internal/bundled"
+	"github.com/microsoft/typescript-go/internal/fourslash"
+	"github.com/microsoft/typescript-go/internal/ls"
+	"github.com/microsoft/typescript-go/internal/lsp/lsproto"
+	"github.com/microsoft/typescript-go/internal/testutil/projecttestutil"
+	"gotest.tools/v3/assert"
+)
+
+func TestDefinition(t *testing.T) {
+	t.Parallel()
+	if !bundled.Embedded {
+		// Without embedding, we'd need to read all of the lib files out from disk into the MapFS.
+		// Just skip this for now.
+		t.Skip("bundled files are not embedded")
+	}
+
+	testCases := []struct {
+		title    string
+		input    string
+		expected map[string]lsproto.Definition
+	}{
+		{
+			title: "localFunction",
+			input: `
+// @filename: index.ts
+function localFunction() { }
+/*localFunction*/localFunction();`,
+			expected: map[string]lsproto.Definition{
+				"localFunction": {
+					Locations: &[]lsproto.Location{{
+						Uri:   ls.FileNameToDocumentURI("/index.ts"),
+						Range: lsproto.Range{Start: lsproto.Position{Character: 9}, End: lsproto.Position{Character: 22}},
+					}},
+				},
+			},
+		},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.title, func(t *testing.T) {
+			t.Parallel()
+			runDefinitionTest(t, testCase.input, testCase.expected)
+		})
+	}
+}
+
+func runDefinitionTest(t *testing.T, input string, expected map[string]lsproto.Definition) {
+	testData := fourslash.ParseTestData(t, input, "/mainFile.ts")
+	file := testData.Files[0].FileName()
+	markerPositions := testData.MarkerPositions
+	ctx := projecttestutil.WithRequestID(t.Context())
+	languageService, done := createLanguageService(ctx, file, map[string]any{
+		file: testData.Files[0].Content,
+	})
+	defer done()
+
+	for markerName, expectedResult := range expected {
+		marker, ok := markerPositions[markerName]
+		if !ok {
+			t.Fatalf("No marker found for '%s'", markerName)
+		}
+		locations, err := languageService.ProvideDefinition(
+			ctx,
+			ls.FileNameToDocumentURI(file),
+			marker.LSPosition)
+		assert.NilError(t, err)
+		assert.DeepEqual(t, *locations, expectedResult)
+	}
+}