Fixed bug where function type literals may omit their '=>'.

Author: DanielRosenwasser

src/compiler/parser.ts

@@ -1274,7 +1274,18 @@ module ts {
             var typeParameters = parseTypeParameters();
             var parameters = parseParameterList(SyntaxKind.OpenParenToken, SyntaxKind.CloseParenToken);
             checkParameterList(parameters);
-            var type = parseOptional(returnToken) ? parseType() : undefined;
+
+            var type: TypeNode;
+
+            if (returnToken === SyntaxKind.EqualsGreaterThanToken) {
+                parseExpected(returnToken);
+                type = parseType();
+            }
+            else if (parseOptional(returnToken)) 
+            {
+                type = parseType();
+            }
+
             return {
                 typeParameters: typeParameters,
                 parameters: parameters,

tests/baselines/reference/functionTypesLackingReturnTypes.errors.txt

@@ -0,0 +1,18 @@
+==== tests/cases/compiler/functionTypesLackingReturnTypes.ts (2 errors) ====
+    
+    // Error (no '=>')
+    function f(x: ()) {
+                    ~
+!!! '=>' expected.
+    }
+    
+    // Error (no '=>')
+    var g: (param);
+                  ~
+!!! '=>' expected.
+    
+    // Okay
+    var h: { () }
+    
+    // Okay
+    var i: { new () }

tests/cases/compiler/functionTypesLackingReturnTypes.ts

@@ -0,0 +1,13 @@
+
+// Error (no '=>')
+function f(x: ()) {
+}
+
+// Error (no '=>')
+var g: (param);
+
+// Okay
+var h: { () }
+
+// Okay
+var i: { new () }