Annotate fewer extracted constants with types

amcasey · amcasey · commit 9efab94dfd00 · 2017-12-15T15:11:17.000-08:00
Expose `isContextSensitive` from the checker and omit type annotations
for expressions for which it returns false.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -171,6 +171,7 @@ namespace ts {
                 node = getParseTreeNode(node, isExpression);
                 return node ? getContextualType(node) : undefined;
             },
+            isContextSensitive,
             getFullyQualifiedName,
             getResolvedSignature: (node, candidatesOutArray, theArgumentCount) => {
                 node = getParseTreeNode(node, isCallLikeExpression);
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
@@ -2739,6 +2739,8 @@ namespace ts {
         getAugmentedPropertiesOfType(type: Type): Symbol[];
         getRootSymbols(symbol: Symbol): Symbol[];
         getContextualType(node: Expression): Type | undefined;
+        /* @internal */ isContextSensitive(node: Expression | MethodDeclaration | ObjectLiteralElementLike | JsxAttributeLike): boolean;
+
         /**
          * returns unknownSignature in the case of an error.
          * @param argumentCount Apparent number of arguments, passed in case of a possibly incomplete call. This should come from an ArgumentListInfo. See `signatureHelp.ts`.
diff --git a/src/services/refactors/extractSymbol.ts b/src/services/refactors/extractSymbol.ts
@@ -1004,7 +1004,7 @@ namespace ts.refactor.extractSymbol {
         const localNameText = getUniqueName(isClassLike(scope) ? "newProperty" : "newLocal", file.text);
         const isJS = isInJavaScriptFile(scope);
 
-        const variableType = isJS
+        const variableType = isJS || !checker.isContextSensitive(node)
             ? undefined
             : checker.typeToTypeNode(checker.getContextualType(node), scope, NodeBuilderFlags.NoTruncation);
 
diff --git a/tests/baselines/reference/extractConstant/extractConstant_StatementInsertionPosition7.ts b/tests/baselines/reference/extractConstant/extractConstant_StatementInsertionPosition7.ts
@@ -15,7 +15,7 @@ const i = 0;
 class C {
     M() {
         for (let j = 0; j < 10; j++) {
-            const newLocal: any = i + 1;
+            const newLocal = i + 1;
             x = /*RENAME*/newLocal;
         }
     }
@@ -25,7 +25,7 @@ class C {
 
 const i = 0;
 class C {
-    private readonly newProperty: any = i + 1;
+    private readonly newProperty = i + 1;
 
     M() {
         for (let j = 0; j < 10; j++) {
@@ -37,7 +37,7 @@ class C {
 // ==SCOPE::Extract to constant in global scope==
 
 const i = 0;
-const newLocal: any = i + 1;
+const newLocal = i + 1;
 class C {
     M() {
         for (let j = 0; j < 10; j++) {
