Revert concepts changes from D41910

These changes caused LibcxxVariantDataFormatterTestCase in lldb to fail
with an assert:

Assertion failed: (Idx < size() && "Out-of-bounds Bit access."),
function operator[], file
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/include/llvm/ADT/SmallBitVector.h,
line 452.

In:

7  clang-10                 0x00000001094b79d9 isAtLeastAsSpecializedAs(clang::Sema&, clang::SourceLocation, clang::FunctionTemplateDecl*, clang::FunctionTemplateDecl*, clang::TemplatePartialOrderingContext, unsigned int) + 1865
8  clang-10                 0x00000001094b7111 clang::Sema::getMoreSpecializedTemplate(clang::FunctionTemplateDecl*, clang::FunctionTemplateDecl*, clang::SourceLocation, clang::TemplatePartialOrderingContext, unsigned int, unsigned int) + 97
9  clang-10                 0x000000010939bf88 clang::isBetterOverloadCandidate(clang::Sema&, clang::OverloadCandidate const&, clang::OverloadCandidate const&, clang::SourceLocation, clang::OverloadCandidateSet::CandidateSetKind) + 1128

Revert "[Concepts] Fix incorrect move out of temporary in D41910"

This reverts commit 11d5fa6e87e3584f72056ecc2b17f88c58323dde.

Revert "[Concepts] Fix crash in D41910"

This reverts commit 12038be20ee6a903cdbd3fddce65535ef683e31d.

Revert "[Concepts] Constrained partial specializations and function overloads."

This reverts commit fc0731b98a67c793862288f8ae334322666214dc.

1 files changed, 10 insertions, 20 deletions

diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index ade8a5a6ac1..699895568b7 100755..100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -1120,11 +1120,11 @@ NamedDecl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
   // Check that we have valid decl-specifiers specified.
   auto CheckValidDeclSpecifiers = [this, &D] {
     // C++ [temp.param]
-    // p1 
+    // p1
     //   template-parameter:
     //     ...
     //     parameter-declaration
-    // p2 
+    // p2
     //   ... A storage class shall not be specified in a template-parameter
     //   declaration.
     // [dcl.typedef]p1:
@@ -3900,9 +3900,7 @@ DeclResult Sema::ActOnVarTemplateSpecialization(
     }
 
     if (isSameAsPrimaryTemplate(VarTemplate->getTemplateParameters(),
-                                Converted) &&
-        (!Context.getLangOpts().ConceptsTS ||
-         !TemplateParams->hasAssociatedConstraints())) {
+                                Converted)) {
       // C++ [temp.class.spec]p9b3:
       //
       //   -- The argument list of the specialization shall not be identical
@@ -3921,8 +3919,8 @@ DeclResult Sema::ActOnVarTemplateSpecialization(
   VarTemplateSpecializationDecl *PrevDecl = nullptr;
 
   if (IsPartialSpecialization)
-    PrevDecl = VarTemplate->findPartialSpecialization(Converted, TemplateParams,
-                                                      InsertPos);
+    // FIXME: Template parameter list matters too
+    PrevDecl = VarTemplate->findPartialSpecialization(Converted, InsertPos);
   else
     PrevDecl = VarTemplate->findSpecialization(Converted, InsertPos);
 
@@ -5275,16 +5273,12 @@ bool Sema::CheckTemplateArgumentList(
       bool PackExpansionIntoNonPack =
           NewArgs[ArgIdx].getArgument().isPackExpansion() &&
           (!(*Param)->isTemplateParameterPack() || getExpandedPackSize(*Param));
-      if (PackExpansionIntoNonPack && (isa<TypeAliasTemplateDecl>(Template) ||
-                                       isa<ConceptDecl>(Template))) {
+      if (PackExpansionIntoNonPack && isa<TypeAliasTemplateDecl>(Template)) {
         // Core issue 1430: we have a pack expansion as an argument to an
         // alias template, and it's not part of a parameter pack. This
         // can't be canonicalized, so reject it now.
-        // As for concepts - we cannot normalize constraints where this
-        // situation exists.
         Diag(NewArgs[ArgIdx].getLocation(),
-             diag::err_template_expansion_into_fixed_list)
-          << (isa<ConceptDecl>(Template) ? 1 : 0)
+             diag::err_alias_template_expansion_into_fixed_list)
           << NewArgs[ArgIdx].getSourceRange();
         Diag((*Param)->getLocation(), diag::note_template_param_here);
         return true;
@@ -7118,7 +7112,6 @@ static bool MatchTemplateParameterKind(Sema &S, NamedDecl *New, NamedDecl *Old,
                                        bool Complain,
                                      Sema::TemplateParameterListEqualKind Kind,
                                        SourceLocation TemplateArgLoc) {
-  // TODO: Concepts: Check constrained-parameter constraints here.
   // Check the actual kind (type, non-type, template).
   if (Old->getKind() != New->getKind()) {
     if (Complain) {
@@ -7820,9 +7813,8 @@ DeclResult Sema::ActOnClassTemplateSpecialization(
   ClassTemplateSpecializationDecl *PrevDecl = nullptr;
 
   if (isPartialSpecialization)
-    PrevDecl = ClassTemplate->findPartialSpecialization(Converted,
-                                                        TemplateParams,
-                                                        InsertPos);
+    // FIXME: Template parameter list matters, too
+    PrevDecl = ClassTemplate->findPartialSpecialization(Converted, InsertPos);
   else
     PrevDecl = ClassTemplate->findSpecialization(Converted, InsertPos);
 
@@ -7846,9 +7838,7 @@ DeclResult Sema::ActOnClassTemplateSpecialization(
                                                       Converted);
 
     if (Context.hasSameType(CanonType,
-                        ClassTemplate->getInjectedClassNameSpecialization()) &&
-        (!Context.getLangOpts().ConceptsTS ||
-         !TemplateParams->hasAssociatedConstraints())) {
+                        ClassTemplate->getInjectedClassNameSpecialization())) {
       // C++ [temp.class.spec]p9b3:
       //
       //   -- The argument list of the specialization shall not be identical