Fix ASI for 'as' operator

Author: RyanCavanaugh

src/compiler/parser.ts

@@ -2822,8 +2822,12 @@ module ts {
                 }
 
                 if (token === SyntaxKind.AsKeyword) {
-                    parseTokenNode();
-                    leftOperand = makeAsExpression(leftOperand, parseType());
+                    if (canParseSemicolon()) {
+                        break;
+                    } else {
+                        parseTokenNode();
+                        leftOperand = makeAsExpression(leftOperand, parseType());
+                    }
                 } else {
                     leftOperand = makeBinaryExpression(leftOperand, parseTokenNode(), parseBinaryExpressionOrHigher(newPrecedence));
                 }

tests/baselines/reference/asOperatorASI.js

@@ -0,0 +1,26 @@
+//// [asOperatorASI.ts]
+class Foo { }
+declare function as(...args: any[]);
+
+// Example 1
+var x = 10
+as `Hello world`; // should not error
+
+// Example 2
+var y = 20
+as(Foo); // should emit
+
+
+//// [asOperatorASI.js]
+var Foo = (function () {
+    function Foo() {
+    }
+    return Foo;
+})();
+// Example 1
+var x = 10;
+(_a = ["Hello world"], _a.raw = ["Hello world"], as(_a)); // should not error
+// Example 2
+var y = 20;
+as(Foo); // should emit
+var _a;

tests/baselines/reference/asOperatorASI.symbols

@@ -0,0 +1,23 @@
+=== tests/cases/conformance/expressions/asOperator/asOperatorASI.ts ===
+class Foo { }
+>Foo : Symbol(Foo, Decl(asOperatorASI.ts, 0, 0))
+
+declare function as(...args: any[]);
+>as : Symbol(as, Decl(asOperatorASI.ts, 0, 13))
+>args : Symbol(args, Decl(asOperatorASI.ts, 1, 20))
+
+// Example 1
+var x = 10
+>x : Symbol(x, Decl(asOperatorASI.ts, 4, 3))
+
+as `Hello world`; // should not error
+>as : Symbol(as, Decl(asOperatorASI.ts, 0, 13))
+
+// Example 2
+var y = 20
+>y : Symbol(y, Decl(asOperatorASI.ts, 8, 3))
+
+as(Foo); // should emit
+>as : Symbol(as, Decl(asOperatorASI.ts, 0, 13))
+>Foo : Symbol(Foo, Decl(asOperatorASI.ts, 0, 0))
+

tests/baselines/reference/asOperatorASI.types

@@ -0,0 +1,28 @@
+=== tests/cases/conformance/expressions/asOperator/asOperatorASI.ts ===
+class Foo { }
+>Foo : Foo
+
+declare function as(...args: any[]);
+>as : (...args: any[]) => any
+>args : any[]
+
+// Example 1
+var x = 10
+>x : number
+>10 : number
+
+as `Hello world`; // should not error
+>as `Hello world` : any
+>as : (...args: any[]) => any
+>`Hello world` : string
+
+// Example 2
+var y = 20
+>y : number
+>20 : number
+
+as(Foo); // should emit
+>as(Foo) : any
+>as : (...args: any[]) => any
+>Foo : typeof Foo
+

tests/cases/conformance/expressions/asOperator/asOperatorASI.ts

@@ -0,0 +1,10 @@
+class Foo { }
+declare function as(...args: any[]);
+
+// Example 1
+var x = 10
+as `Hello world`; // should not error
+
+// Example 2
+var y = 20
+as(Foo); // should emit