Go to the name of the function

Author: shinichy

Diff for: internal/ast/utilities.go

@@ -2650,3 +2650,8 @@ func getPragmaArgument(pragma *Pragma, name string) string {
 	}
 	return ""
 }
+
+func IsRightSideOfPropertyAccess(node *Node) bool {
+	parent := node.Parent
+	return IsPropertyAccessExpression(parent) && parent.AsPropertyAccessExpression().Name() == node
+}

Diff for: internal/checker/checker.go

@@ -5584,7 +5584,7 @@ func (c *Checker) checkDecorators(node *ast.Node) {
 
 func (c *Checker) checkDecorator(node *ast.Node) {
 	c.checkGrammarDecorator(node.AsDecorator())
-	signature := c.getResolvedSignature(node, nil, CheckModeNormal)
+	signature := c.GetResolvedSignature(node, nil, CheckModeNormal)
 	c.checkDeprecatedSignature(signature, node)
 	returnType := c.getReturnTypeOfSignature(signature)
 	if returnType.flags&TypeFlagsAny != 0 {
@@ -7820,7 +7820,7 @@ func (c *Checker) checkImportCallExpression(node *ast.Node) *Type {
  */
 func (c *Checker) checkCallExpression(node *ast.Node, checkMode CheckMode) *Type {
 	c.checkGrammarTypeArguments(node, node.TypeArgumentList())
-	signature := c.getResolvedSignature(node, nil /*candidatesOutArray*/, checkMode)
+	signature := c.GetResolvedSignature(node, nil /*candidatesOutArray*/, checkMode)
 	if signature == c.resolvingSignature {
 		// CheckMode.SkipGenericFunctions is enabled and this is a call to a generic function that
 		// returns a function type. We defer checking and return silentNeverType.
@@ -7864,7 +7864,7 @@ func (c *Checker) checkDeprecatedSignature(sig *Signature, node *ast.Node) {
 	}
 	if sig.declaration != nil && sig.declaration.Flags&ast.NodeFlagsDeprecated != 0 {
 		suggestionNode := c.getDeprecatedSuggestionNode(node)
-		name := tryGetPropertyAccessOrIdentifierToString(getInvokedExpression(node))
+		name := tryGetPropertyAccessOrIdentifierToString(GetInvokedExpression(node))
 		c.addDeprecatedSuggestionWithSignature(suggestionNode, sig.declaration, name, c.signatureToString(sig))
 	}
 }
@@ -7901,7 +7901,7 @@ func (c *Checker) isSymbolOrSymbolForCall(node *ast.Node) bool {
  *    the function will fill it up with appropriate candidate signatures
  * @return a signature of the call-like expression or undefined if one can't be found
  */
-func (c *Checker) getResolvedSignature(node *ast.Node, candidatesOutArray *[]*Signature, checkMode CheckMode) *Signature {
+func (c *Checker) GetResolvedSignature(node *ast.Node, candidatesOutArray *[]*Signature, checkMode CheckMode) *Signature {
 	links := c.signatureLinks.Get(node)
 	// If getResolvedSignature has already been called, we will have cached the resolvedSignature.
 	// However, it is possible that either candidatesOutArray was not passed in the first time,
@@ -9521,7 +9521,7 @@ func (c *Checker) checkTaggedTemplateExpression(node *ast.Node) *Type {
 	if !c.checkGrammarTaggedTemplateChain(node.AsTaggedTemplateExpression()) {
 		c.checkGrammarTypeArguments(node, node.TypeArgumentList())
 	}
-	signature := c.getResolvedSignature(node, nil, CheckModeNormal)
+	signature := c.GetResolvedSignature(node, nil, CheckModeNormal)
 	c.checkDeprecatedSignature(signature, node)
 	return c.getReturnTypeOfSignature(signature)
 }
@@ -10961,7 +10961,7 @@ func (c *Checker) isUncalledFunctionReference(node *ast.Node, symbol *ast.Symbol
 		if parent == nil {
 			parent = node.Parent
 		}
-		if isCallLikeExpression(parent) {
+		if IsCallLikeExpression(parent) {
 			return isCallOrNewExpression(parent) && ast.IsIdentifier(node) && c.hasMatchingArgument(parent, node)
 		}
 		return core.Every(symbol.Declarations, func(d *ast.Node) bool {
@@ -12261,7 +12261,7 @@ func (c *Checker) checkInstanceOfExpression(left *ast.Expression, right *ast.Exp
 	if !IsTypeAny(leftType) && c.allTypesAssignableToKind(leftType, TypeFlagsPrimitive) {
 		c.error(left, diagnostics.The_left_hand_side_of_an_instanceof_expression_must_be_of_type_any_an_object_type_or_a_type_parameter)
 	}
-	signature := c.getResolvedSignature(left.Parent, nil /*candidatesOutArray*/, checkMode)
+	signature := c.GetResolvedSignature(left.Parent, nil /*candidatesOutArray*/, checkMode)
 	if signature == c.resolvingSignature {
 		// CheckMode.SkipGenericFunctions is enabled and this is a call to a generic function that
 		// returns a function type. We defer checking and return silentNeverType.
@@ -27529,7 +27529,7 @@ func (c *Checker) getContextualTypeForArgumentAtIndex(callTarget *ast.Node, argI
 	if c.signatureLinks.Get(callTarget).resolvedSignature == c.resolvingSignature {
 		signature = c.resolvingSignature
 	} else {
-		signature = c.getResolvedSignature(callTarget, nil, CheckModeNormal)
+		signature = c.GetResolvedSignature(callTarget, nil, CheckModeNormal)
 	}
 	if isJsxOpeningLikeElement(callTarget) && argIndex == 0 {
 		return c.getEffectiveFirstArgumentForJsxSignature(signature, callTarget)

Diff for: internal/checker/flow.go

@@ -2040,7 +2040,7 @@ func (c *Checker) getEffectsSignature(node *ast.Node) *Signature {
 		case len(signatures) == 1 && signatures[0].typeParameters == nil:
 			signature = signatures[0]
 		case core.Some(signatures, c.hasTypePredicateOrNeverReturnType):
-			signature = c.getResolvedSignature(node, nil, CheckModeNormal)
+			signature = c.GetResolvedSignature(node, nil, CheckModeNormal)
 		}
 		if !(signature != nil && c.hasTypePredicateOrNeverReturnType(signature)) {
 			signature = c.unknownSignature

Diff for: internal/checker/jsx.go

@@ -125,7 +125,7 @@ func (c *Checker) checkJsxOpeningLikeElementOrOpeningFragment(node *ast.Node) {
 	c.checkJsxPreconditions(node)
 	c.markJsxAliasReferenced(node)
 	if isNodeOpeningLikeElement {
-		sig := c.getResolvedSignature(node, nil, CheckModeNormal)
+		sig := c.GetResolvedSignature(node, nil, CheckModeNormal)
 		c.checkDeprecatedSignature(sig, node)
 		elementTypeConstraint := c.getJsxElementTypeTypeAt(node)
 		if elementTypeConstraint != nil {

Diff for: internal/checker/utilities.go

@@ -1294,7 +1294,7 @@ func isThisTypeParameter(t *Type) bool {
 	return t.flags&TypeFlagsTypeParameter != 0 && t.AsTypeParameter().isThisType
 }
 
-func isCallLikeExpression(node *ast.Node) bool {
+func IsCallLikeExpression(node *ast.Node) bool {
 	switch node.Kind {
 	case ast.KindJsxOpeningElement, ast.KindJsxSelfClosingElement, ast.KindCallExpression, ast.KindNewExpression,
 		ast.KindTaggedTemplateExpression, ast.KindDecorator:
@@ -1829,6 +1829,10 @@ func getNonRestParameterCount(sig *Signature) int {
 	return len(sig.parameters) - core.IfElse(signatureHasRestParameter(sig), 1, 0)
 }
 
+func GetDeclaration(sig *Signature) *ast.Node {
+	return sig.declaration
+}
+
 func minAndMax[T any](slice []T, getValue func(value T) int) (int, int) {
 	var minValue, maxValue int
 	for i, element := range slice {
@@ -2113,7 +2117,7 @@ func tryGetPropertyAccessOrIdentifierToString(expr *ast.Node) string {
 	return ""
 }
 
-func getInvokedExpression(node *ast.Node) *ast.Node {
+func GetInvokedExpression(node *ast.Node) *ast.Node {
 	switch node.Kind {
 	case ast.KindTaggedTemplateExpression:
 		return node.AsTaggedTemplateExpression().Tag

Diff for: internal/ls/definition.go

@@ -3,6 +3,7 @@ package ls
 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/scanner"
 )
@@ -15,25 +16,70 @@ func (l *LanguageService) ProvideDefinitions(fileName string, position int) []Lo
 	}
 
 	checker := program.GetTypeChecker()
+	calledDeclaration := tryGetSignatureDeclaration(checker, node)
+	if calledDeclaration != nil {
+		name := ast.GetNameOfDeclaration(calledDeclaration)
+		if name != nil {
+			return 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([]Location, 0, len(symbol.Declarations))
-		for _, decl := range symbol.Declarations {
-			file := ast.GetSourceFileOfNode(decl)
-			loc := decl.Loc
-			pos := scanner.GetTokenPosOfNode(decl, file, false /*includeJSDoc*/)
+		return createLocationsFromDeclarations(symbol.Declarations)
+	}
+	return nil
+}
+
+func createLocationsFromDeclarations(declarations []*ast.Node) []Location {
+	locations := make([]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, Location{
+			FileName: file.FileName(),
+			Range:    core.NewTextRange(pos, loc.End()),
+		})
+	}
+	return locations
+}
 
-			locations = append(locations, Location{
-				FileName: file.FileName(),
-				Range:    core.NewTextRange(pos, loc.End()),
-			})
+/** 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 !ast.IsRightSideOfPropertyAccess(n)
+	})
+
+	callLike := target.Parent
+	if callLike != nil && checker.IsCallLikeExpression(callLike) && checker.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, nil, checker.CheckModeNormal)
+	}
+
+	// Don't go to a function type, go to the value having that type.
+	var declaration *ast.Node
+	if signature != nil && checker.GetDeclaration(signature) != nil {
+		declaration = checker.GetDeclaration(signature)
+		if ast.IsFunctionLike(declaration) && !ast.IsFunctionTypeNode(declaration) {
+			return declaration
 		}
-		return locations
 	}
+
 	return nil
 }