Revert r359949 "[clang] adding explicit(bool) from c++2a"

This caused Clang to start erroring on the following:

  struct S {
    template <typename = int> explicit S();
  };

  struct T : S {};

  struct U : T {
    U();
  };
  U::U() {}

  $ clang -c /tmp/x.cc
  /tmp/x.cc:10:4: error: call to implicitly-deleted default constructor of 'T'
  U::U() {}
     ^
  /tmp/x.cc:5:12: note: default constructor of 'T' is implicitly deleted
    because base class 'S' has no default constructor
  struct T : S {};
             ^
  1 error generated.

See discussion on the cfe-commits email thread.

This also reverts the follow-ups r359966 and r359968.

> this patch adds support for the explicit bool specifier.
>
> Changes:
> - The parsing for the explicit(bool) specifier was added in ParseDecl.cpp.
> - The storage of the explicit specifier was changed. the explicit specifier was stored as a boolean value in the FunctionDeclBitfields and in the DeclSpec class. now it is stored as a PointerIntPair<Expr*, 2> with a flag and a potential expression in CXXConstructorDecl, CXXDeductionGuideDecl, CXXConversionDecl and in the DeclSpec class.
> - Following the AST change, Serialization, ASTMatchers, ASTComparator and ASTPrinter were adapted.
> - Template instantiation was adapted to instantiate the potential expressions of the explicit(bool) specifier When instantiating their associated declaration.
> - The Add*Candidate functions were adapted, they now take a Boolean indicating if the context allowing explicit constructor or conversion function and this boolean is used to remove invalid overloads that required template instantiation to be detected.
> - Test for Semantic and Serialization were added.
>
> This patch is not yet complete. I still need to check that interaction with CTAD and deduction guides is correct. and add more tests for AST operations. But I wanted first feedback.
> Perhaps this patch should be spited in smaller patches, but making each patch testable as a standalone may be tricky.
>
> Patch by Tyker
>
> Differential Revision: https://reviews.llvm.org/D60934

llvm-svn: 360024

1 files changed, 8 insertions, 8 deletions

diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index b2f80ebd119..58ad439747e 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -1109,7 +1109,7 @@ NamedDecl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
     if (DS.isVirtualSpecified())
       EmitDiag(DS.getVirtualSpecLoc());
 
-    if (DS.hasExplicitSpecifier())
+    if (DS.isExplicitSpecified())
       EmitDiag(DS.getExplicitSpecLoc());
 
     if (DS.isNoreturnSpecified())
@@ -1789,8 +1789,8 @@ struct ConvertConstructorToDeductionGuideTransform {
       return nullptr;
     TypeSourceInfo *NewTInfo = TLB.getTypeSourceInfo(SemaRef.Context, NewType);
 
-    return buildDeductionGuide(TemplateParams, CD->getExplicitSpecifier(),
-                               NewTInfo, CD->getBeginLoc(), CD->getLocation(),
+    return buildDeductionGuide(TemplateParams, CD->isExplicit(), NewTInfo,
+                               CD->getBeginLoc(), CD->getLocation(),
                                CD->getEndLoc());
   }
 
@@ -1819,8 +1819,8 @@ struct ConvertConstructorToDeductionGuideTransform {
       Params.push_back(NewParam);
     }
 
-    return buildDeductionGuide(Template->getTemplateParameters(),
-                               ExplicitSpecifier(), TSI, Loc, Loc, Loc);
+    return buildDeductionGuide(Template->getTemplateParameters(), false, TSI,
+                               Loc, Loc, Loc);
   }
 
 private:
@@ -1970,7 +1970,7 @@ private:
   }
 
   NamedDecl *buildDeductionGuide(TemplateParameterList *TemplateParams,
-                                 ExplicitSpecifier ES, TypeSourceInfo *TInfo,
+                                 bool Explicit, TypeSourceInfo *TInfo,
                                  SourceLocation LocStart, SourceLocation Loc,
                                  SourceLocation LocEnd) {
     DeclarationNameInfo Name(DeductionGuideName, Loc);
@@ -1979,8 +1979,8 @@ private:
 
     // Build the implicit deduction guide template.
     auto *Guide =
-        CXXDeductionGuideDecl::Create(SemaRef.Context, DC, LocStart, ES, Name,
-                                      TInfo->getType(), TInfo, LocEnd);
+        CXXDeductionGuideDecl::Create(SemaRef.Context, DC, LocStart, Explicit,
+                                      Name, TInfo->getType(), TInfo, LocEnd);
     Guide->setImplicit();
     Guide->setParams(Params);