feat(48231): allow unique symbol for constant variables (microsoft#48270)

Author: a-tarasyuk

Diff for: src/compiler/checker.ts

@@ -43992,13 +43992,11 @@ namespace ts {
                 if (node.type.kind !== SyntaxKind.SymbolKeyword) {
                     return grammarErrorOnNode(node.type, Diagnostics._0_expected, tokenToString(SyntaxKind.SymbolKeyword));
                 }
-
                 let parent = walkUpParenthesizedTypes(node.parent);
                 if (isInJSFile(parent) && isJSDocTypeExpression(parent)) {
-                    parent = parent.parent;
-                    if (isJSDocTypeTag(parent)) {
-                        // walk up past JSDoc comment node
-                        parent = parent.parent.parent;
+                    const host = getJSDocHost(parent);
+                    if (host) {
+                        parent = getSingleVariableOfVariableStatement(host) || host;
                     }
                 }
                 switch (parent.kind) {

Diff for: tests/baselines/reference/uniqueSymbolsDeclarationsInJs.js

@@ -23,6 +23,9 @@ class C {
     readonlyCall = Symbol();
     readwriteCall = Symbol();
 }
+
+/** @type {unique symbol} */
+const a = Symbol();
 
 
 //// [uniqueSymbolsDeclarationsInJs-out.js]
@@ -46,6 +49,8 @@ class C {
     static { this.readonlyStaticTypeAndCall = Symbol(); }
     static { this.readwriteStaticCall = Symbol(); }
 }
+/** @type {unique symbol} */
+const a = Symbol();
 
 
 //// [uniqueSymbolsDeclarationsInJs-out.d.ts]
@@ -71,3 +76,5 @@ declare class C {
     readonly readonlyCall: symbol;
     readwriteCall: symbol;
 }
+/** @type {unique symbol} */
+declare const a: unique symbol;

Diff for: tests/baselines/reference/uniqueSymbolsDeclarationsInJs.symbols

@@ -41,3 +41,8 @@ class C {
 >Symbol : Symbol(Symbol, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2019.symbol.d.ts, --, --))
 }
 
+/** @type {unique symbol} */
+const a = Symbol();
+>a : Symbol(a, Decl(uniqueSymbolsDeclarationsInJs.js, 26, 5))
+>Symbol : Symbol(Symbol, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2019.symbol.d.ts, --, --))
+

Diff for: tests/baselines/reference/uniqueSymbolsDeclarationsInJs.types

@@ -46,3 +46,9 @@ class C {
 >Symbol : SymbolConstructor
 }
 
+/** @type {unique symbol} */
+const a = Symbol();
+>a : symbol
+>Symbol() : unique symbol
+>Symbol : SymbolConstructor
+

Diff for: tests/cases/conformance/types/uniqueSymbol/uniqueSymbolsDeclarationsInJs.ts

@@ -31,3 +31,6 @@ class C {
     readonlyCall = Symbol();
     readwriteCall = Symbol();
 }
+
+/** @type {unique symbol} */
+const a = Symbol();