Sema: Hack up CSDiag for removal of multiple parameter lists

Author: slavapestov

lib/Sema/CSDiag.cpp

@@ -3421,11 +3421,15 @@ static bool candidatesHaveAnyDefaultValues(
     auto function = dyn_cast_or_null<AbstractFunctionDecl>(cand.getDecl());
     if (!function) continue;
 
-    auto paramLists = function->getParameterLists();
-    if (cand.level >= paramLists.size()) continue;
+    if (function->getImplicitSelfDecl()) {
+      if (cand.level != 1)
+        return false;
+    } else {
+      if (cand.level != 0)
+        return false;
+    }
 
-    auto paramList = paramLists[cand.level];
-    for (auto param : *paramList) {
+    for (auto param : *function->getParameters()) {
       if (param->getDefaultArgumentKind() != DefaultArgumentKind::None)
         return true;
     }
@@ -3456,11 +3460,15 @@ static Optional<unsigned> getElementForScalarInitOfArg(
   auto function = dyn_cast_or_null<AbstractFunctionDecl>(cand.getDecl());
   if (!function) return getElementForScalarInitSimple(tupleTy);
 
-  auto paramLists = function->getParameterLists();
-  if (cand.level >= paramLists.size())
-    return getElementForScalarInitSimple(tupleTy);
+  if (function->getImplicitSelfDecl()) {
+    if (cand.level != 1)
+      return getElementForScalarInitSimple(tupleTy);
+  } else {
+    if (cand.level != 0)
+      return getElementForScalarInitSimple(tupleTy);
+  }
 
-  auto paramList = paramLists[cand.level];
+  auto paramList = function->getParameters();
   if (tupleTy->getNumElements() != paramList->size()) 
     return getElementForScalarInitSimple(tupleTy);
 

lib/Sema/CalleeCandidateInfo.cpp

@@ -90,10 +90,18 @@ ArrayRef<Identifier> UncurriedCandidate::getArgumentLabels(
   scratch.clear();
   if (auto decl = getDecl()) {
     if (auto func = dyn_cast<AbstractFunctionDecl>(decl)) {
-      // Retrieve the argument labels of the corresponding parameter list.
-      if (level < func->getNumParameterLists()) {
-        auto paramList = func->getParameterList(level);
-        for (auto param : *paramList) {
+      if (func->getImplicitSelfDecl()) {
+        if (level == 0) {
+          scratch.push_back(Identifier());
+          return scratch;
+        }
+
+        --level;
+      }
+
+      if (level == 0) {
+        // Retrieve the argument labels of the corresponding parameter list.
+        for (auto param : *func->getParameters()) {
           scratch.push_back(param->getArgumentName());
         }
         return scratch;