feat(56600): JSDoc @callback doesn't support this parameters via @this (microsoft#56610)

Author: a-tarasyuk

src/compiler/checker.ts

@@ -597,6 +597,7 @@ import {
     isJSDocSatisfiesTag,
     isJSDocSignature,
     isJSDocTemplateTag,
+    isJSDocThisTag,
     isJSDocTypeAlias,
     isJSDocTypeAssertion,
     isJSDocTypedefTag,
@@ -15079,6 +15080,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             let flags = SignatureFlags.None;
             let minArgumentCount = 0;
             let thisParameter: Symbol | undefined;
+            let thisTag: JSDocThisTag | undefined = isInJSFile(declaration) ? getJSDocThisTag(declaration) : undefined;
             let hasThisParameter = false;
             const iife = getImmediatelyInvokedFunctionExpression(declaration);
             const isJSConstructSignature = isJSDocConstructSignature(declaration);
@@ -15096,6 +15098,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             // signature.
             for (let i = isJSConstructSignature ? 1 : 0; i < declaration.parameters.length; i++) {
                 const param = declaration.parameters[i];
+                if (isInJSFile(param) && isJSDocThisTag(param)) {
+                    thisTag = param;
+                    continue;
+                }
 
                 let paramSymbol = param.symbol;
                 const type = isJSDocParameterTag(param) ? (param.typeExpression && param.typeExpression.type) : param.type;
@@ -15139,11 +15145,8 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 }
             }
 
-            if (isInJSFile(declaration)) {
-                const thisTag = getJSDocThisTag(declaration);
-                if (thisTag && thisTag.typeExpression) {
-                    thisParameter = createSymbolWithType(createSymbol(SymbolFlags.FunctionScopedVariable, InternalSymbolName.This), getTypeFromTypeNode(thisTag.typeExpression));
-                }
+            if (thisTag && thisTag.typeExpression) {
+                thisParameter = createSymbolWithType(createSymbol(SymbolFlags.FunctionScopedVariable, InternalSymbolName.This), getTypeFromTypeNode(thisTag.typeExpression));
             }
 
             const hostDeclaration = isJSDocSignature(declaration) ? getEffectiveJSDocHost(declaration) : declaration;

src/compiler/parser.ts

@@ -9343,7 +9343,7 @@ namespace Parser {
             function parseNestedTypeLiteral(typeExpression: JSDocTypeExpression | undefined, name: EntityName, target: PropertyLikeParse, indent: number) {
                 if (typeExpression && isObjectOrObjectArrayTypeReference(typeExpression.type)) {
                     const pos = getNodePos();
-                    let child: JSDocPropertyLikeTag | JSDocTypeTag | JSDocTemplateTag | false;
+                    let child: JSDocPropertyLikeTag | JSDocTypeTag | JSDocTemplateTag | JSDocThisTag | false;
                     let children: JSDocPropertyLikeTag[] | undefined;
                     while (child = tryParse(() => parseChildParameterOrPropertyTag(target, indent, name))) {
                         if (child.kind === SyntaxKind.JSDocParameterTag || child.kind === SyntaxKind.JSDocPropertyTag) {
@@ -9635,7 +9635,7 @@ namespace Parser {
                 return parseChildParameterOrPropertyTag(PropertyLikeParse.Property, indent) as JSDocTypeTag | JSDocPropertyTag | JSDocTemplateTag | false;
             }
 
-            function parseChildParameterOrPropertyTag(target: PropertyLikeParse, indent: number, name?: EntityName): JSDocTypeTag | JSDocPropertyTag | JSDocParameterTag | JSDocTemplateTag | false {
+            function parseChildParameterOrPropertyTag(target: PropertyLikeParse, indent: number, name?: EntityName): JSDocTypeTag | JSDocPropertyTag | JSDocParameterTag | JSDocTemplateTag | JSDocThisTag | false {
                 let canParseTag = true;
                 let seenAsterisk = false;
                 while (true) {
@@ -9672,7 +9672,7 @@ namespace Parser {
                 }
             }
 
-            function tryParseChildTag(target: PropertyLikeParse, indent: number): JSDocTypeTag | JSDocPropertyTag | JSDocParameterTag | JSDocTemplateTag | false {
+            function tryParseChildTag(target: PropertyLikeParse, indent: number): JSDocTypeTag | JSDocPropertyTag | JSDocParameterTag | JSDocTemplateTag | JSDocThisTag | false {
                 Debug.assert(token() === SyntaxKind.AtToken);
                 const start = scanner.getTokenFullStart();
                 nextTokenJSDoc();
@@ -9694,6 +9694,8 @@ namespace Parser {
                         break;
                     case "template":
                         return parseTemplateTag(start, tagName, indent, indentText);
+                    case "this":
+                        return parseThisTag(start, tagName, indent, indentText);
                     default:
                         return false;
                 }

tests/baselines/reference/callbackTag4.symbols

@@ -0,0 +1,23 @@
+//// [tests/cases/conformance/jsdoc/callbackTag4.ts] ////
+
+=== ./a.js ===
+/**
+ * @callback C
+ * @this {{ a: string, b: number }}
+ * @param {string} a
+ * @param {number} b
+ * @returns {boolean}
+ */
+
+/** @type {C} */
+const cb = function (a, b) {
+>cb : Symbol(cb, Decl(a.js, 9, 5))
+>a : Symbol(a, Decl(a.js, 9, 21))
+>b : Symbol(b, Decl(a.js, 9, 23))
+
+    this
+>this : Symbol(this)
+
+    return true
+}
+

tests/baselines/reference/callbackTag4.types

@@ -0,0 +1,25 @@
+//// [tests/cases/conformance/jsdoc/callbackTag4.ts] ////
+
+=== ./a.js ===
+/**
+ * @callback C
+ * @this {{ a: string, b: number }}
+ * @param {string} a
+ * @param {number} b
+ * @returns {boolean}
+ */
+
+/** @type {C} */
+const cb = function (a, b) {
+>cb : C
+>function (a, b) {    this    return true} : (this: { a: string; b: number; }, a: string, b: number) => boolean
+>a : string
+>b : number
+
+    this
+>this : { a: string; b: number; }
+
+    return true
+>true : true
+}
+

tests/cases/conformance/jsdoc/callbackTag4.ts

@@ -0,0 +1,19 @@
+// @allowJs: true
+// @checkJs: true
+// @strict: true
+// @noEmit: true
+// @filename: ./a.js
+
+/**
+ * @callback C
+ * @this {{ a: string, b: number }}
+ * @param {string} a
+ * @param {number} b
+ * @returns {boolean}
+ */
+
+/** @type {C} */
+const cb = function (a, b) {
+    this
+    return true
+}