diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 079d942df4e..cb6a34392c0 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4577,12 +4577,7 @@ namespace ts {
         function getErasedSignature(signature: Signature): Signature {
             if (!signature.typeParameters) return signature;
             if (!signature.erasedSignatureCache) {
-                if (signature.target) {
-                    signature.erasedSignatureCache = instantiateSignature(getErasedSignature(signature.target), signature.mapper);
-                }
-                else {
-                    signature.erasedSignatureCache = instantiateSignature(signature, createTypeEraser(signature.typeParameters), /*eraseTypeParameters*/ true);
-                }
+                signature.erasedSignatureCache = instantiateSignature(signature, createTypeEraser(signature.typeParameters), /*eraseTypeParameters*/ true);
             }
             return signature.erasedSignatureCache;
         }