Merge pull request #1621 from Microsoft/narrowingOfAny

Type guard narrows type any in a primitive type check

src/compiler/checker.ts

@@ -4590,8 +4590,8 @@ module ts {
         // Get the narrowed type of a given symbol at a given location
         function getNarrowedTypeOfSymbol(symbol: Symbol, node: Node) {
             var type = getTypeOfSymbol(symbol);
-            // Only narrow when symbol is variable of an object, union, or type parameter type
-            if (node && symbol.flags & SymbolFlags.Variable && type.flags & (TypeFlags.ObjectType | TypeFlags.Union | TypeFlags.TypeParameter)) {
+            // Only narrow when symbol is variable of type any or an object, union, or type parameter type
+            if (node && symbol.flags & SymbolFlags.Variable && type.flags & (TypeFlags.Any | TypeFlags.ObjectType | TypeFlags.Union | TypeFlags.TypeParameter)) {
                 loop: while (node.parent) {
                     var child = node;
                     node = node.parent;
@@ -4647,21 +4647,16 @@ module ts {
                 if (expr.left.kind !== SyntaxKind.TypeOfExpression || expr.right.kind !== SyntaxKind.StringLiteral) {
                     return type;
                 }
-
                 var left = <TypeOfExpression>expr.left;
                 var right = <LiteralExpression>expr.right;
-                if (left.expression.kind !== SyntaxKind.Identifier ||
-                    getResolvedSymbol(<Identifier>left.expression) !== symbol) {
-
+                if (left.expression.kind !== SyntaxKind.Identifier || getResolvedSymbol(<Identifier>left.expression) !== symbol) {
                     return type;
                 }
-
                 var t = right.text;
                 var checkType: Type = t === "string" ? stringType : t === "number" ? numberType : t === "boolean" ? booleanType : emptyObjectType;
                 if (expr.operator === SyntaxKind.ExclamationEqualsEqualsToken) {
                     assumeTrue = !assumeTrue;
                 }
-
                 if (assumeTrue) {
                     // The assumed result is true. If check was for a primitive type, that type is the narrowed type. Otherwise we can
                     // remove the primitive types from the narrowed type.
@@ -4705,8 +4700,8 @@ module ts {
             }
 
             function narrowTypeByInstanceof(type: Type, expr: BinaryExpression, assumeTrue: boolean): Type {
-                // Check that assumed result is true and we have variable symbol on the left
-                if (!assumeTrue || expr.left.kind !== SyntaxKind.Identifier || getResolvedSymbol(<Identifier>expr.left) !== symbol) {
+                // Check that type is not any, assumed result is true, and we have variable symbol on the left
+                if (type.flags & TypeFlags.Any || !assumeTrue || expr.left.kind !== SyntaxKind.Identifier || getResolvedSymbol(<Identifier>expr.left) !== symbol) {
                     return type;
                 }
                 // Check that right operand is a function type with a prototype property

src/compiler/types.ts

@@ -1331,8 +1331,6 @@ module ts {
     // Generic class and interface types
     export interface GenericType extends InterfaceType, TypeReference {
         instantiations: Map<TypeReference>;   // Generic instantiation cache
-        openReferenceTargets: GenericType[];  // Open type reference targets
-        openReferenceChecks: Map<boolean>;    // Open type reference check cache
     }
 
     export interface TupleType extends ObjectType {

tests/baselines/reference/typeGuardsWithAny.errors.txt

@@ -0,0 +1,49 @@
+tests/cases/conformance/expressions/typeGuards/typeGuardsWithAny.ts(11,7): error TS2339: Property 'p' does not exist on type 'string'.
+tests/cases/conformance/expressions/typeGuards/typeGuardsWithAny.ts(18,7): error TS2339: Property 'p' does not exist on type 'number'.
+tests/cases/conformance/expressions/typeGuards/typeGuardsWithAny.ts(25,7): error TS2339: Property 'p' does not exist on type 'boolean'.
+
+
+==== tests/cases/conformance/expressions/typeGuards/typeGuardsWithAny.ts (3 errors) ====
+    var x: any = { p: 0 };
+    
+    if (x instanceof Object) {
+        x.p; // No error, type any unaffected by instanceof type guard
+    }
+    else {
+        x.p; // No error, type any unaffected by instanceof type guard
+    }
+    
+    if (typeof x === "string") {
+        x.p; // Error, type any narrowed by primitive type check
+          ~
+!!! error TS2339: Property 'p' does not exist on type 'string'.
+    }
+    else {
+        x.p; // No error, type unaffected in this branch
+    }
+    
+    if (typeof x === "number") {
+        x.p; // Error, type any narrowed by primitive type check
+          ~
+!!! error TS2339: Property 'p' does not exist on type 'number'.
+    }
+    else {
+        x.p; // No error, type unaffected in this branch
+    }
+    
+    if (typeof x === "boolean") {
+        x.p; // Error, type any narrowed by primitive type check
+          ~
+!!! error TS2339: Property 'p' does not exist on type 'boolean'.
+    }
+    else {
+        x.p; // No error, type unaffected in this branch
+    }
+    
+    if (typeof x === "object") {
+        x.p; // No error, type any only affected by primitive type check
+    }
+    else {
+        x.p; // No error, type unaffected in this branch
+    }
+    

tests/baselines/reference/typeGuardsWithAny.js

@@ -1,18 +1,71 @@
 //// [typeGuardsWithAny.ts]
 var x: any = { p: 0 };
+
 if (x instanceof Object) {
-    x.p; // No error, type any unaffected by type guard
+    x.p; // No error, type any unaffected by instanceof type guard
 }
 else {
-    x.p; // No error, type any unaffected by type guard
+    x.p; // No error, type any unaffected by instanceof type guard
+}
+
+if (typeof x === "string") {
+    x.p; // Error, type any narrowed by primitive type check
+}
+else {
+    x.p; // No error, type unaffected in this branch
+}
+
+if (typeof x === "number") {
+    x.p; // Error, type any narrowed by primitive type check
+}
+else {
+    x.p; // No error, type unaffected in this branch
+}
+
+if (typeof x === "boolean") {
+    x.p; // Error, type any narrowed by primitive type check
+}
+else {
+    x.p; // No error, type unaffected in this branch
+}
+
+if (typeof x === "object") {
+    x.p; // No error, type any only affected by primitive type check
+}
+else {
+    x.p; // No error, type unaffected in this branch
 }
 
 
 //// [typeGuardsWithAny.js]
 var x = { p: 0 };
 if (x instanceof Object) {
-    x.p; // No error, type any unaffected by type guard
+    x.p; // No error, type any unaffected by instanceof type guard
 }
 else {
-    x.p; // No error, type any unaffected by type guard
+    x.p; // No error, type any unaffected by instanceof type guard
+}
+if (typeof x === "string") {
+    x.p; // Error, type any narrowed by primitive type check
+}
+else {
+    x.p; // No error, type unaffected in this branch
+}
+if (typeof x === "number") {
+    x.p; // Error, type any narrowed by primitive type check
+}
+else {
+    x.p; // No error, type unaffected in this branch
+}
+if (typeof x === "boolean") {
+    x.p; // Error, type any narrowed by primitive type check
+}
+else {
+    x.p; // No error, type unaffected in this branch
+}
+if (typeof x === "object") {
+    x.p; // No error, type any only affected by primitive type check
+}
+else {
+    x.p; // No error, type unaffected in this branch
 }

tests/baselines/reference/typeGuardsWithAny.types

@@ -1,23 +0,0 @@
-=== tests/cases/conformance/expressions/typeGuards/typeGuardsWithAny.ts ===
-var x: any = { p: 0 };
->x : any
->{ p: 0 } : { p: number; }
->p : number
-
-if (x instanceof Object) {
->x instanceof Object : boolean
->x : any
->Object : ObjectConstructor
-
-    x.p; // No error, type any unaffected by type guard
->x.p : any
->x : any
->p : any
-}
-else {
-    x.p; // No error, type any unaffected by type guard
->x.p : any
->x : any
->p : any
-}
-

tests/cases/conformance/expressions/typeGuards/typeGuardsWithAny.ts

@@ -1,7 +1,36 @@
 var x: any = { p: 0 };
+
 if (x instanceof Object) {
-    x.p; // No error, type any unaffected by type guard
+    x.p; // No error, type any unaffected by instanceof type guard
 }
 else {
-    x.p; // No error, type any unaffected by type guard
+    x.p; // No error, type any unaffected by instanceof type guard
+}
+
+if (typeof x === "string") {
+    x.p; // Error, type any narrowed by primitive type check
+}
+else {
+    x.p; // No error, type unaffected in this branch
+}
+
+if (typeof x === "number") {
+    x.p; // Error, type any narrowed by primitive type check
+}
+else {
+    x.p; // No error, type unaffected in this branch
+}
+
+if (typeof x === "boolean") {
+    x.p; // Error, type any narrowed by primitive type check
+}
+else {
+    x.p; // No error, type unaffected in this branch
+}
+
+if (typeof x === "object") {
+    x.p; // No error, type any only affected by primitive type check
+}
+else {
+    x.p; // No error, type unaffected in this branch
 }