fix(52828): No signature help in parameter declaration before , and ) (#52840)

Author: a-tarasyuk

src/services/signatureHelp.ts

@@ -16,6 +16,7 @@ import {
     emptyArray,
     Expression,
     factory,
+    findAncestor,
     findContainingList,
     findIndex,
     findPrecedingToken,
@@ -30,7 +31,9 @@ import {
     Identifier,
     identity,
     InternalSymbolName,
+    isArrayBindingPattern,
     isBinaryExpression,
+    isBindingElement,
     isBlock,
     isCallOrNewExpression,
     isFunctionTypeNode,
@@ -41,6 +44,8 @@ import {
     isJsxOpeningLikeElement,
     isMethodDeclaration,
     isNoSubstitutionTemplateLiteral,
+    isObjectBindingPattern,
+    isParameter,
     isPropertyAccessExpression,
     isSourceFile,
     isSourceFileJS,
@@ -387,8 +392,11 @@ function countBinaryExpressionParameters(b: BinaryExpression): number {
 }
 
 function tryGetParameterInfo(startingToken: Node, position: number, sourceFile: SourceFile, checker: TypeChecker): ArgumentListInfo | undefined {
-    const info = getContextualSignatureLocationInfo(startingToken, sourceFile, position, checker);
-    if (!info) return undefined;
+    const node = getAdjustedNode(startingToken);
+    if (node === undefined) return undefined;
+
+    const info = getContextualSignatureLocationInfo(node, sourceFile, position, checker);
+    if (info === undefined) return undefined;
     const { contextualType, argumentIndex, argumentCount, argumentsSpan } = info;
 
     // for optional function condition.
@@ -404,24 +412,34 @@ function tryGetParameterInfo(startingToken: Node, position: number, sourceFile:
     return { isTypeParameterList: false, invocation, argumentsSpan, argumentIndex, argumentCount };
 }
 
+function getAdjustedNode(node: Node) {
+    switch (node.kind) {
+        case SyntaxKind.OpenParenToken:
+        case SyntaxKind.CommaToken:
+            return node;
+        default:
+            return findAncestor(node.parent, n =>
+                isParameter(n) ? true : isBindingElement(n) || isObjectBindingPattern(n) || isArrayBindingPattern(n) ? false : "quit");
+    }
+}
+
 interface ContextualSignatureLocationInfo { readonly contextualType: Type; readonly argumentIndex: number; readonly argumentCount: number; readonly argumentsSpan: TextSpan; }
-function getContextualSignatureLocationInfo(startingToken: Node, sourceFile: SourceFile, position: number, checker: TypeChecker): ContextualSignatureLocationInfo | undefined {
-    if (startingToken.kind !== SyntaxKind.OpenParenToken && startingToken.kind !== SyntaxKind.CommaToken) return undefined;
-    const { parent } = startingToken;
+function getContextualSignatureLocationInfo(node: Node, sourceFile: SourceFile, position: number, checker: TypeChecker): ContextualSignatureLocationInfo | undefined {
+    const { parent } = node;
     switch (parent.kind) {
         case SyntaxKind.ParenthesizedExpression:
         case SyntaxKind.MethodDeclaration:
         case SyntaxKind.FunctionExpression:
         case SyntaxKind.ArrowFunction:
-            const info = getArgumentOrParameterListInfo(startingToken, position, sourceFile);
+            const info = getArgumentOrParameterListInfo(node, position, sourceFile);
             if (!info) return undefined;
             const { argumentIndex, argumentCount, argumentsSpan } = info;
             const contextualType = isMethodDeclaration(parent) ? checker.getContextualTypeForObjectLiteralElement(parent) : checker.getContextualType(parent as ParenthesizedExpression | FunctionExpression | ArrowFunction);
             return contextualType && { contextualType, argumentIndex, argumentCount, argumentsSpan };
         case SyntaxKind.BinaryExpression: {
             const highestBinary = getHighestBinary(parent as BinaryExpression);
             const contextualType = checker.getContextualType(highestBinary);
-            const argumentIndex = startingToken.kind === SyntaxKind.OpenParenToken ? 0 : countBinaryExpressionParameters(parent as BinaryExpression) - 1;
+            const argumentIndex = node.kind === SyntaxKind.OpenParenToken ? 0 : countBinaryExpressionParameters(parent as BinaryExpression) - 1;
             const argumentCount = countBinaryExpressionParameters(highestBinary);
             return contextualType && { contextualType, argumentIndex, argumentCount, argumentsSpan: createTextSpanFromNode(parent) };
         }