Don't rely on truthiness.

DanielRosenwasser · DanielRosenwasser · commit 1905eac824e6 · 2016-01-11T12:22:40.000-08:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -5636,7 +5636,7 @@ namespace ts {
              * See signatureAssignableTo, compareSignaturesIdentical
              */
             function signatureRelatedTo(source: Signature, target: Signature, reportErrors: boolean): Ternary {
-                return compareSignaturesRelated(source, target, /*ignoreReturnTypes*/ false, reportErrors && reportError, isRelatedTo);
+                return compareSignaturesRelated(source, target, /*ignoreReturnTypes*/ false, reportErrors ? reportError : undefined, isRelatedTo);
             }
 
             function signaturesIdenticalTo(source: Type, target: Type, kind: SignatureKind): Ternary {

Original file line number	Diff line number	Diff line change
`@@ -5636,7 +5636,7 @@ namespace ts {`
`5636`	`5636`	`* See signatureAssignableTo, compareSignaturesIdentical`
`5637`	`5637`	`*/`
`5638`	`5638`	`function signatureRelatedTo(source: Signature, target: Signature, reportErrors: boolean): Ternary {`
`5639`		`- return compareSignaturesRelated(source, target, /ignoreReturnTypes/ false, reportErrors && reportError, isRelatedTo);`
	`5639`	`+ return compareSignaturesRelated(source, target, /ignoreReturnTypes/ false, reportErrors ? reportError : undefined, isRelatedTo);`
`5640`	`5640`	`}`
`5641`	`5641`
`5642`	`5642`	`function signaturesIdenticalTo(source: Type, target: Type, kind: SignatureKind): Ternary {`