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

Authored by Rakete1111 on May 3 2019, 5:09 PM.


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

this patch adds support for the explicit bool specifier.


  • 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: 359949