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.

2 files changed, 8 insertions, 10 deletions

diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 3351f76151e..0240984d75a 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -2176,14 +2176,12 @@ ASTDeclReader::VisitClassTemplateSpecializationDeclImpl(
 
 void ASTDeclReader::VisitClassTemplatePartialSpecializationDecl(
                                     ClassTemplatePartialSpecializationDecl *D) {
-  // We need to read the template params first because redeclarable is going to
-  // need them for profiling
+  RedeclarableResult Redecl = VisitClassTemplateSpecializationDeclImpl(D);
+
   TemplateParameterList *Params = Record.readTemplateParameterList();
   D->TemplateParams = Params;
   D->ArgsAsWritten = Record.readASTTemplateArgumentListInfo();
 
-  RedeclarableResult Redecl = VisitClassTemplateSpecializationDeclImpl(D);
-
   // These are read/set from/to the first declaration.
   if (ThisDeclID == Redecl.getFirstID()) {
     D->InstantiatedFromMember.setPointer(
@@ -2281,12 +2279,12 @@ ASTDeclReader::VisitVarTemplateSpecializationDeclImpl(
 ///        using Template(Partial)SpecializationDecl as input type.
 void ASTDeclReader::VisitVarTemplatePartialSpecializationDecl(
     VarTemplatePartialSpecializationDecl *D) {
+  RedeclarableResult Redecl = VisitVarTemplateSpecializationDeclImpl(D);
+
   TemplateParameterList *Params = Record.readTemplateParameterList();
   D->TemplateParams = Params;
   D->ArgsAsWritten = Record.readASTTemplateArgumentListInfo();
 
-  RedeclarableResult Redecl = VisitVarTemplateSpecializationDeclImpl(D);
-
   // These are read/set from/to the first declaration.
   if (ThisDeclID == Redecl.getFirstID()) {
     D->InstantiatedFromMember.setPointer(
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index 66f4db855a3..8931dc05fdd 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -1539,11 +1539,11 @@ void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
 
 void ASTDeclWriter::VisitClassTemplatePartialSpecializationDecl(
                                     ClassTemplatePartialSpecializationDecl *D) {
+  VisitClassTemplateSpecializationDecl(D);
+
   Record.AddTemplateParameterList(D->getTemplateParameters());
   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
 
-  VisitClassTemplateSpecializationDecl(D);
-
   // These are read/set from/to the first declaration.
   if (D->getPreviousDecl() == nullptr) {
     Record.AddDeclRef(D->getInstantiatedFromMember());
@@ -1599,11 +1599,11 @@ void ASTDeclWriter::VisitVarTemplateSpecializationDecl(
 
 void ASTDeclWriter::VisitVarTemplatePartialSpecializationDecl(
     VarTemplatePartialSpecializationDecl *D) {
+  VisitVarTemplateSpecializationDecl(D);
+
   Record.AddTemplateParameterList(D->getTemplateParameters());
   Record.AddASTTemplateArgumentListInfo(D->getTemplateArgsAsWritten());
 
-  VisitVarTemplateSpecializationDecl(D);
-
   // These are read/set from/to the first declaration.
   if (D->getPreviousDecl() == nullptr) {
     Record.AddDeclRef(D->getInstantiatedFromMember());