CSApply: Handle unbound references to methods found via dynamic lookup

Author: AnthonyLatsis

lib/Sema/CSApply.cpp

@@ -903,11 +903,6 @@ namespace {
                                bool baseIsInstance) {
       ValueDecl *member = choice.getDecl();
 
-      // FIXME: We should finish plumbing this through for dynamic
-      // lookup as well.
-      if (choice.getKind() == OverloadChoiceKind::DeclViaDynamic)
-        return false;
-
       // If we're inside a selector expression, don't build the thunk.
       // Were not actually going to emit the member reference, just
       // look at the AST.
@@ -921,9 +916,11 @@ namespace {
       if (!baseIsInstance && member->isInstanceMember())
         return true;
 
-      // Bound optional method references are represented via
-      // DynamicMemberRefExpr instead of a curry thunk.
-      if (member->getAttrs().hasAttribute<OptionalAttr>())
+      // Bound member references that are '@objc optional' or found via dynamic
+      // lookup are always represented via DynamicMemberRefExpr instead of a
+      // curry thunk.
+      if (member->getAttrs().hasAttribute<OptionalAttr>() ||
+          choice.getKind() == OverloadChoiceKind::DeclViaDynamic)
         return false;
 
       // Figure out how many argument lists we need.
@@ -1590,8 +1587,8 @@ namespace {
       }
 
       // Handle dynamic references.
-      if (isDynamic || (!needsCurryThunk &&
-                        member->getAttrs().hasAttribute<OptionalAttr>())) {
+      if (!needsCurryThunk &&
+          (isDynamic || member->getAttrs().hasAttribute<OptionalAttr>())) {
         base = cs.coerceToRValue(base);
         Expr *ref = new (context) DynamicMemberRefExpr(base, dotLoc, memberRef,
                                                        memberLoc);

test/SILGen/dynamic_lookup.swift

@@ -117,6 +117,23 @@ func opt_to_class(_ obj: AnyObject) {
   // CHECK:   return [[RESULT]] : $()
 }
 
+// CHECK-LABEL: sil hidden [ossa] @$s14dynamic_lookup20opt_to_class_unboundyyF : $@convention(thin) () -> () {
+// CHECK: bb0:
+// CHECK:   metatype $@thin AnyObject.Protocol
+// CHECK:   function_ref @$[[THUNK_NAME:[_a-zA-Z0-9]+]]
+// CHECK: } // end sil function '$s14dynamic_lookup20opt_to_class_unboundyyF'
+//
+// CHECK: sil private [ossa] @$[[THUNK_NAME]] : $@convention(thin) (@guaranteed AnyObject) -> @owned Optional<@callee_guaranteed () -> ()> {
+// CHECK: bb0(%0 : @guaranteed $AnyObject):
+// CHECK:   [[OPENED:%[0-9]+]] = open_existential_ref %0 : $AnyObject to $[[OPENED_TY:@opened\("[-A-F0-9]+"\) AnyObject]]
+// CHECK:   [[OPENED_COPY:%[0-9]+]] = copy_value [[OPENED]]
+// CHECK:   alloc_stack $Optional<@callee_guaranteed () -> ()>
+// CHECK:   dynamic_method_br [[OPENED_COPY]] : $[[OPENED_TY]], #X.f!foreign, bb1, bb2
+// CHECK: } // end sil function '$[[THUNK_NAME]]'
+func opt_to_class_unbound() {
+  let f = AnyObject.f
+}
+
 // CHECK-LABEL: sil hidden [ossa] @$s14dynamic_lookup20forced_without_outer{{[_0-9a-zA-Z]*}}F
 func forced_without_outer(_ obj: AnyObject) {
   // CHECK: dynamic_method_br