Index: clang/lib/Sema/SemaCoroutine.cpp
===================================================================
--- clang/lib/Sema/SemaCoroutine.cpp
+++ clang/lib/Sema/SemaCoroutine.cpp
@@ -375,7 +375,7 @@
 // returning await_suspend that results in a guaranteed tail call to the target
 // coroutine.
 static Expr *maybeTailCall(Sema &S, QualType RetType, Expr *E,
-                           SourceLocation Loc, bool IsImplicit) {
+                           SourceLocation Loc) {
   if (RetType->isReferenceType())
     return nullptr;
   Type const *T = RetType.getTypePtr();
@@ -482,7 +482,7 @@
 
     // Experimental support for coroutine_handle returning await_suspend.
     if (Expr *TailCallSuspend =
-            maybeTailCall(S, RetType, AwaitSuspend, Loc, IsImplicit))
+            maybeTailCall(S, RetType, AwaitSuspend, Loc))
       // Note that we don't wrap the expression with ExprWithCleanups here
       // because that might interfere with tailcall contract (e.g. inserting
       // clean up instructions in-between tailcall and return). Instead