feat(44720): allow renaming string literal in switch/case (microsoft#45084)

Author: a-tarasyuk

src/services/findAllReferences.ts

@@ -2003,13 +2003,13 @@ namespace ts.FindAllReferences {
         }
 
         function getReferencesForStringLiteral(node: StringLiteralLike, sourceFiles: readonly SourceFile[], checker: TypeChecker, cancellationToken: CancellationToken): SymbolAndEntries[] {
-            const type = getContextualTypeOrAncestorTypeNodeType(node, checker);
+            const type = getContextualTypeFromParentOrAncestorTypeNode(node, checker);
             const references = flatMap(sourceFiles, sourceFile => {
                 cancellationToken.throwIfCancellationRequested();
                 return mapDefined(getPossibleSymbolReferenceNodes(sourceFile, node.text), ref => {
                     if (isStringLiteralLike(ref) && ref.text === node.text) {
                         if (type) {
-                            const refType = getContextualTypeOrAncestorTypeNodeType(ref, checker);
+                            const refType = getContextualTypeFromParentOrAncestorTypeNode(ref, checker);
                             if (type !== checker.getStringType() && type === refType) {
                                 return nodeEntry(ref, EntryKind.StringLiteral);
                             }

src/services/rename.ts

@@ -15,7 +15,7 @@ namespace ts.Rename {
         const symbol = typeChecker.getSymbolAtLocation(node);
         if (!symbol) {
             if (isStringLiteralLike(node)) {
-                const type = getContextualTypeOrAncestorTypeNodeType(node, typeChecker);
+                const type = getContextualTypeFromParentOrAncestorTypeNode(node, typeChecker);
                 if (type && ((type.flags & TypeFlags.StringLiteral) || (
                     (type.flags & TypeFlags.Union) && every((type as UnionType).types, type => !!(type.flags & TypeFlags.StringLiteral))
                 ))) {

src/services/utilities.ts

@@ -796,16 +796,9 @@ namespace ts {
         return lastTypeNode;
     }
 
-    export function getContextualTypeOrAncestorTypeNodeType(node: Expression, checker: TypeChecker) {
-        const contextualType = checker.getContextualType(node);
-        if (contextualType) {
-            return contextualType;
-        }
-
-        const parent = node.parent;
-        if (parent && isBinaryExpression(parent) && isEqualityOperatorKind(parent.operatorToken.kind)) {
-            return checker.getTypeAtLocation(node === parent.left ? parent.right : parent.left);
-        }
+    export function getContextualTypeFromParentOrAncestorTypeNode(node: Expression, checker: TypeChecker): Type | undefined {
+        const contextualType = getContextualTypeFromParent(node, checker);
+        if (contextualType) return contextualType;
 
         const ancestorTypeNode = getAncestorTypeNode(node);
         return ancestorTypeNode && checker.getTypeAtLocation(ancestorTypeNode);

tests/cases/fourslash/renameStringLiteralTypes3.ts

@@ -0,0 +1,17 @@
+/// <reference path='fourslash.ts' />
+
+////type Foo = "[|a|]" | "b";
+////
+////class C {
+////    p: Foo = "[|a|]";
+////    m() {
+////        switch (this.p) {
+////            case "[|a|]":
+////                return 1;
+////            case "b":
+////                return 2;
+////        }
+////    }
+////}
+
+verify.rangesWithSameTextAreRenameLocations("a");