Fixes type predicate crash bug

tinganho · tinganho · commit 752e0ba00384 · 2015-06-18T23:04:05.000+08:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -5761,6 +5761,7 @@ namespace ts {
                 let signature = getResolvedSignature(expr);
 
                 if (signature.typePredicate &&
+                    expr.arguments[signature.typePredicate.parameterIndex] &&
                     getSymbolAtLocation(expr.arguments[signature.typePredicate.parameterIndex]) === symbol) {
 
                     if (!assumeTrue) {
diff --git a/tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts b/tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts
@@ -23,6 +23,10 @@ function hasMissingIsKeyword(): x {
     return true;
 }
 
+function hasMissingParameter(): x is A {
+    return true;
+}
+
 function hasMissingTypeInTypeGuardType(x): x is {
     return true;
 }
@@ -132,4 +136,10 @@ function b6([a, b, p1], p2, p3): p1 is A {
 
 function b7({a, b, c: {p1}}, p2, p3): p1 is A {
     return true;
+}
+
+// Should not crash the compiler
+var x: A;
+if (hasMissingParameter()) {
+    x.propA;
 }

Original file line number	Diff line number	Diff line change
`@@ -23,6 +23,10 @@ function hasMissingIsKeyword(): x {`
`23`	`23`	`return true;`
`24`	`24`	`}`
`25`	`25`
	`26`	`+function hasMissingParameter(): x is A {`
	`27`	`+ return true;`
	`28`	`+}`
	`29`	`+`
`26`	`30`	`function hasMissingTypeInTypeGuardType(x): x is {`
`27`	`31`	`return true;`
`28`	`32`	`}`
`@@ -132,4 +136,10 @@ function b6([a, b, p1], p2, p3): p1 is A {`
`132`	`136`
`133`	`137`	`function b7({a, b, c: {p1}}, p2, p3): p1 is A {`
`134`	`138`	`return true;`
	`139`	`+}`
	`140`	`+`
	`141`	`+// Should not crash the compiler`
	`142`	`+var x: A;`
	`143`	`+if (hasMissingParameter()) {`
	`144`	`+ x.propA;`
`135`	`145`	`}`