fix(44701): allow renaming string literal in rhs/lhs of equality (#44708)

src/services/utilities.ts

@@ -802,6 +802,11 @@ namespace ts {
             return contextualType;
         }
 
+        const parent = node.parent;
+        if (parent && isBinaryExpression(parent) && isEqualityOperatorKind(parent.operatorToken.kind)) {
+            return checker.getTypeAtLocation(node === parent.left ? parent.right : parent.left);
+        }
+
         const ancestorTypeNode = getAncestorTypeNode(node);
         return ancestorTypeNode && checker.getTypeAtLocation(ancestorTypeNode);
     }

tests/cases/fourslash/renameStringLiteralOk1.ts

@@ -9,10 +9,3 @@
 //// ff.f = '[|foo|]'
 
 verify.rangesWithSameTextAreRenameLocations("foo");
-
-interface Foo {
-    f: 'foo' | 'bar'
-}
-const d: 'foo' = 'foo'
-declare const f: Foo
-f.f = 'foo'

tests/cases/fourslash/renameStringLiteralTypes2.ts

@@ -0,0 +1,22 @@
+/// <reference path='fourslash.ts' />
+
+////type Foo = "[|a|]" | "b";
+////
+////class C {
+////    p: Foo = "[|a|]";
+////    m() {
+////        if (this.p === "[|a|]") {}
+////        if ("[|a|]" === this.p) {}
+////
+////        if (this.p !== "[|a|]") {}
+////        if ("[|a|]" !== this.p) {}
+////
+////        if (this.p == "[|a|]") {}
+////        if ("[|a|]" == this.p) {}
+////
+////        if (this.p != "[|a|]") {}
+////        if ("[|a|]" != this.p) {}
+////    }
+////}
+
+verify.rangesWithSameTextAreRenameLocations("a");