Several fixes to JS typing of functions and methods (#1960)

Author: ahejlsberg

internal/ast/utilities.go

@@ -571,7 +571,7 @@ func IsClassElement(node *Node) bool {
 	return false
 }
 
-func isMethodOrAccessor(node *Node) bool {
+func IsMethodOrAccessor(node *Node) bool {
 	switch node.Kind {
 	case KindMethodDeclaration, KindGetAccessor, KindSetAccessor:
 		return true
@@ -580,7 +580,7 @@ func isMethodOrAccessor(node *Node) bool {
 }
 
 func IsPrivateIdentifierClassElementDeclaration(node *Node) bool {
-	return (IsPropertyDeclaration(node) || isMethodOrAccessor(node)) && IsPrivateIdentifier(node.Name())
+	return (IsPropertyDeclaration(node) || IsMethodOrAccessor(node)) && IsPrivateIdentifier(node.Name())
 }
 
 func IsObjectLiteralOrClassExpressionMethodOrAccessor(node *Node) bool {

internal/checker/checker.go

@@ -19101,11 +19101,9 @@ func (c *Checker) getSignaturesOfSymbol(symbol *ast.Symbol) []*Signature {
 		}
 		// If this is a function or method declaration, get the signature from the @type tag for the sake of optional parameters.
 		// Exclude contextually-typed kinds because we already apply the @type tag to the context, plus applying it here to the initializer would suppress checks that the two are compatible.
-		if ast.IsFunctionExpressionOrArrowFunction(decl) || ast.IsObjectLiteralMethod(decl) {
-			if sig := c.getSignatureOfFullSignatureType(decl); sig != nil {
-				result = append(result, sig)
-				continue
-			}
+		if sig := c.getSignatureOfFullSignatureType(decl); sig != nil {
+			result = append(result, sig)
+			continue
 		}
 		result = append(result, c.getSignatureFromDeclaration(decl))
 	}
@@ -19123,6 +19121,14 @@ func (c *Checker) getSignatureFromDeclaration(declaration *ast.Node) *Signature
 	minArgumentCount := 0
 	hasThisParameter := false
 	iife := ast.GetImmediatelyInvokedFunctionExpression(declaration)
+	isUntypedSignatureInJSFile := iife == nil &&
+		ast.IsInJSFile(declaration) &&
+		(ast.IsFunctionExpression(declaration) || ast.IsArrowFunction(declaration) || ast.IsMethodOrAccessor(declaration) || ast.IsFunctionDeclaration(declaration) || ast.IsConstructorDeclaration(declaration)) &&
+		core.Every(declaration.Parameters(), func(param *ast.Node) bool { return param.Type() == nil }) &&
+		c.getContextualType(declaration, ContextFlagsSignature) == nil
+	if isUntypedSignatureInJSFile {
+		flags |= SignatureFlagsIsUntypedSignatureInJSFile
+	}
 	for i, param := range declaration.Parameters() {
 		paramSymbol := param.Symbol()
 		typeNode := param.Type()
@@ -19343,7 +19349,7 @@ func (c *Checker) getReturnTypeFromAnnotation(declaration *ast.Node) *Type {
 }
 
 func (c *Checker) getSignatureOfFullSignatureType(node *ast.Node) *Signature {
-	if ast.IsInJSFile(node) && ast.IsFunctionLike(node) && node.FunctionLikeData().FullSignature != nil {
+	if ast.IsInJSFile(node) && (ast.IsFunctionDeclaration(node) || ast.IsMethodDeclaration(node) || ast.IsFunctionExpressionOrArrowFunction(node)) && node.FunctionLikeData().FullSignature != nil {
 		return c.getSingleCallSignature(c.getTypeFromTypeNode(node.FunctionLikeData().FullSignature))
 	}
 	return nil

internal/checker/emitresolver.go

@@ -458,13 +458,20 @@ func (r *emitResolver) IsImplementationOfOverload(node *ast.SignatureDeclaration
 		//       function foo(a: any) { // This is implementation of the overloads
 		//           return a;
 		//       }
-		return len(signaturesOfSymbol) > 1 ||
-			// If there is single signature for the symbol, it is overload if that signature isn't coming from the node
-			// e.g.: function foo(a: string): string;
-			//       function foo(a: any) { // This is implementation of the overloads
-			//           return a;
-			//       }
-			(len(signaturesOfSymbol) == 1 && signaturesOfSymbol[0].declaration != node)
+		if len(signaturesOfSymbol) > 1 {
+			return true
+		}
+		// If there is single signature for the symbol, it is overload if that signature isn't coming from the node
+		// e.g.: function foo(a: string): string;
+		//       function foo(a: any) { // This is implementation of the overloads
+		//           return a;
+		//       }
+		if len(signaturesOfSymbol) == 1 {
+			declaration := signaturesOfSymbol[0].declaration
+			if declaration != node && declaration.Flags&ast.NodeFlagsJSDoc == 0 {
+				return true
+			}
+		}
 	}
 	return false
 }

testdata/baselines/reference/conformance/jsdocTypeParameterTagConflict.types

@@ -6,7 +6,7 @@
  * @param {2} a
  */
 export function conflictingParam(a) { return true }
->conflictingParam : (a: 2) => true
+>conflictingParam : (a: 1) => true
 >a : 2
 >true : true
 
@@ -15,7 +15,7 @@ export function conflictingParam(a) { return true }
  * @return {false}
  */
 export function conflictingReturn(b) { return false }
->conflictingReturn : (b: 3) => false
+>conflictingReturn : (b: 3) => true
 >b : 3
 >false : false
 
@@ -26,7 +26,7 @@ export function conflictingReturn(b) { return false }
  * @return {false}
  */
 export function conflictingBoth(d) { return false }
->conflictingBoth : (d: 5) => false
+>conflictingBoth : (c: 4) => true
 >d : 5
 >false : false
 

testdata/baselines/reference/submodule/compiler/argumentsObjectCreatesRestForJs.errors.txt

@@ -1,22 +1,18 @@
 main.js(3,9): error TS2554: Expected 0 arguments, but got 3.
-main.js(5,1): error TS2554: Expected 2 arguments, but got 0.
-main.js(6,16): error TS2554: Expected 2 arguments, but got 3.
+main.js(6,16): error TS2554: Expected 0-2 arguments, but got 3.
 
 
-==== main.js (3 errors) ====
+==== main.js (2 errors) ====
     function allRest() { arguments; }
     allRest();
     allRest(1, 2, 3);
             ~~~~~~~
 !!! error TS2554: Expected 0 arguments, but got 3.
     function someRest(x, y) { arguments; }
     someRest(); // x and y are still optional because they are in a JS file
-    ~~~~~~~~
-!!! error TS2554: Expected 2 arguments, but got 0.
-!!! related TS6210 main.js:4:19: An argument for 'x' was not provided.
     someRest(1, 2, 3);
                    ~
-!!! error TS2554: Expected 2 arguments, but got 3.
+!!! error TS2554: Expected 0-2 arguments, but got 3.
 
     /**
      * @param {number} x - a thing

testdata/baselines/reference/submodule/compiler/argumentsPropertyNameInJsMode1.errors.txt

@@ -1,4 +1,4 @@
-a.js(9,7): error TS2554: Expected 1 arguments, but got 3.
+a.js(9,7): error TS2554: Expected 0-1 arguments, but got 3.
 
 
 ==== a.js (1 errors) ====
@@ -12,5 +12,5 @@ a.js(9,7): error TS2554: Expected 1 arguments, but got 3.
 
     f2(1, 2, 3);
           ~~~~
-!!! error TS2554: Expected 1 arguments, but got 3.
+!!! error TS2554: Expected 0-1 arguments, but got 3.
 

testdata/baselines/reference/submodule/compiler/argumentsPropertyNameInJsMode2.errors.txt

@@ -1,4 +1,4 @@
-a.js(5,6): error TS2554: Expected 1 arguments, but got 3.
+a.js(5,6): error TS2554: Expected 0-1 arguments, but got 3.
 
 
 ==== a.js (1 errors) ====
@@ -8,5 +8,5 @@ a.js(5,6): error TS2554: Expected 1 arguments, but got 3.
 
     f(1, 2, 3);
          ~~~~
-!!! error TS2554: Expected 1 arguments, but got 3.
+!!! error TS2554: Expected 0-1 arguments, but got 3.
 

testdata/baselines/reference/submodule/compiler/argumentsReferenceInFunction1_Js.errors.txt

@@ -1,5 +1,5 @@
 index.js(1,25): error TS7006: Parameter 'f' implicitly has an 'any' type.
-index.js(13,29): error TS2345: Argument of type 'IArguments' is not assignable to parameter of type '[f: any]'.
+index.js(13,29): error TS2345: Argument of type 'IArguments' is not assignable to parameter of type '[f?: any]'.
 
 
 ==== index.js (2 errors) ====
@@ -19,6 +19,6 @@ index.js(13,29): error TS2345: Argument of type 'IArguments' is not assignable t
     const debuglog = function() {
       return format.apply(null, arguments);
                                 ~~~~~~~~~
-!!! error TS2345: Argument of type 'IArguments' is not assignable to parameter of type '[f: any]'.
+!!! error TS2345: Argument of type 'IArguments' is not assignable to parameter of type '[f?: any]'.
     };