Short-circuit semantic operations within with blocks

Author: mhegazy

src/compiler/checker.ts

@@ -3815,6 +3815,11 @@ module ts {
         // Return the contextual type for a given expression node. During overload resolution, a contextual type may temporarily
         // be "pushed" onto a node using the contextualType property.
         function getContextualType(node: Expression): Type {
+            if (isInsideWithStatementBody(node)) {
+                // We cannot answer semantic questions within a with block, do not proceed any further
+                return undefined;
+            }
+
             if (node.contextualType) {
                 return node.contextualType;
             }
@@ -6681,7 +6686,20 @@ module ts {
             return findChildAtPosition(sourceFile);
         }
 
-        function getSymbolsInScope(location: Node, meaning: SymbolFlags): Symbol[] {
+        function isInsideWithStatementBody(node: Node): boolean {
+            if (node) {
+                while (node.parent) {
+                    if (node.parent.kind === SyntaxKind.WithStatement && (<WithStatement>node.parent).statement === node) {
+                        return true;
+                    }
+                    node = node.parent;
+                }
+            }
+
+            return false;
+        }
+
+        function getSymbolsInScope(location: Node, meaning: SymbolFlags): Symbol[]{
             var symbols: SymbolTable = {};
             var memberFlags: NodeFlags = 0;
             function copySymbol(symbol: Symbol, meaning: SymbolFlags) {
@@ -6701,6 +6719,12 @@ module ts {
                     }
                 }
             }
+
+            if (isInsideWithStatementBody(location)) {
+                // We cannot answer semantic questions within a with block, do not proceed any further
+                return [];
+            }
+
             while (location) {
                 if (location.locals && !isGlobalSourceFile(location)) {
                     copySymbols(location.locals, meaning);
@@ -6973,6 +6997,11 @@ module ts {
         }
 
         function getSymbolInfo(node: Node) {
+            if (isInsideWithStatementBody(node)) {
+                // We cannot answer semantic questions within a with block, do not proceed any further
+                return undefined;
+            }
+
             if (isDeclarationOrFunctionExpressionOrCatchVariableName(node)) {
                 // This is a declaration, call getSymbolOfNode
                 return getSymbolOfNode(node.parent);
@@ -7027,9 +7056,15 @@ module ts {
         }
 
         function getTypeOfNode(node: Node): Type {
+            if (isInsideWithStatementBody(node)) {
+                // We cannot answer semantic questions within a with block, do not proceed any further
+                return unknownType;
+            }
+
             if (isExpression(node)) {
                 return getTypeOfExpression(<Expression>node);
             }
+
             if (isTypeNode(node)) {
                 return getTypeFromTypeNode(<TypeNode>node);
             }

tests/cases/fourslash/findAllRefsInsideWithBlock.ts

@@ -0,0 +1,16 @@
+/// <reference path='fourslash.ts'/>
+
+////var x = 0;
+////
+////with ({}) {
+////    var y = x;  // Reference of x here should not be picked
+////    /*2*/y++;        // also reference for y should be ignored
+////}
+////
+////x = /*1*/x + 1;
+
+goTo.marker('1');
+verify.referencesCountIs(3);
+
+goTo.marker('2');
+verify.referencesCountIs(1);

tests/cases/fourslash/memberListInWithBlock.ts

@@ -15,8 +15,10 @@ goTo.marker('1');
 verify.memberListIsEmpty();
 
 goTo.marker('2');
+// Only keywords should show in completion, no members or types
 verify.not.completionListContains("foo");
 verify.not.completionListContains("f");
 verify.not.completionListContains("c");
 verify.not.completionListContains("d");
 verify.not.completionListContains("x");
+verify.not.completionListContains("Object");

tests/cases/fourslash/memberListInWithBlock2.ts

@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts'/>
+
+////interface IFoo {
+////    a: number;
+////}
+////
+////with (x) {
+////    var y: IFoo = { /*1*/ }; 
+////}
+
+goTo.marker('1');
+verify.memberListIsEmpty();

tests/cases/fourslash/memberListInWithBlock3.ts

@@ -0,0 +1,7 @@
+/// <reference path='fourslash.ts'/>
+
+////var x = { a: 0 };
+////with(x./*1*/
+
+goTo.marker('1');
+verify.memberListContains("a");