Properly guard for undefined in getTypeReferenceArity

ahejlsberg · ahejlsberg · commit 4e56fc0d272e · 2016-08-22T09:49:26.000-07:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -4979,7 +4979,7 @@ namespace ts {
         }
 
         function getTypeReferenceArity(type: TypeReference): number {
-            return type.target.typeParameters.length;
+            return type.target.typeParameters ? type.target.typeParameters.length : 0;
         }
 
         // Get type from reference to class or interface

Original file line number	Diff line number	Diff line change
`@@ -4979,7 +4979,7 @@ namespace ts {`
`4979`	`4979`	`}`
`4980`	`4980`
`4981`	`4981`	`function getTypeReferenceArity(type: TypeReference): number {`
`4982`		`- return type.target.typeParameters.length;`
	`4982`	`+ return type.target.typeParameters ? type.target.typeParameters.length : 0;`
`4983`	`4983`	`}`
`4984`	`4984`
`4985`	`4985`	`// Get type from reference to class or interface`