[CSApply] Don't attempt covariant result type erasure for parameters

of method references.

Author: hborla

lib/Sema/CSApply.cpp

@@ -1720,7 +1720,8 @@ namespace {
         return forceUnwrapIfExpected(result, memberLocator);
       }
 
-      if (member->getInterfaceType()->hasDynamicSelfType()) {
+      auto *func = dyn_cast<FuncDecl>(member);
+      if (func && func->getResultInterfaceType()->hasDynamicSelfType()) {
         refTy = refTy->replaceCovariantResultType(containerTy, 2);
         adjustedRefTy = adjustedRefTy->replaceCovariantResultType(
             containerTy, 2);

test/Sema/dynamic_self_implicit_conversions.swift

@@ -74,3 +74,10 @@ extension Generic where T == Never {
     _ = Generic()[]
   }
 }
+
+final class Final {
+  static func useSelf(_ body: (Self) -> ()) {}
+}
+func testNoErasure(_ body: (Final) -> ()) {
+  return Final.useSelf(body)
+}