[c++1z] Synthesize implicit deduction guides from constructors on demand. Rank
such guides below explicit ones, and ensure that references to the class's
template parameters are not treated as forwarding references.
We make a few tweaks to the wording in the current standard:
1) The constructor parameter list is copied faithfully to the deduction guide,
without losing default arguments or a varargs ellipsis (which the standard
wording loses by omission).
2) If the class template declares no constructors, we add a T() -> T<...> guide
(which will only ever work if T has default arguments for all non-pack
template parameters).
3) If the class template declares nothing that looks like a copy or move
constructor, we add a T(T<...>) -> T<...> guide.
#2 and #3 follow from the "pretend we had a class type with these constructors"
philosophy for deduction guides.
llvm-svn: 295007
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 1539a52..8416140 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -3872,42 +3872,45 @@
return QualType(T, 0);
}
+TemplateArgument ASTContext::getInjectedTemplateArg(NamedDecl *Param) {
+ TemplateArgument Arg;
+ if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
+ QualType ArgType = getTypeDeclType(TTP);
+ if (TTP->isParameterPack())
+ ArgType = getPackExpansionType(ArgType, None);
+
+ Arg = TemplateArgument(ArgType);
+ } else if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
+ Expr *E = new (*this) DeclRefExpr(
+ NTTP, /*enclosing*/false,
+ NTTP->getType().getNonLValueExprType(*this),
+ Expr::getValueKindForType(NTTP->getType()), NTTP->getLocation());
+
+ if (NTTP->isParameterPack())
+ E = new (*this) PackExpansionExpr(DependentTy, E, NTTP->getLocation(),
+ None);
+ Arg = TemplateArgument(E);
+ } else {
+ auto *TTP = cast<TemplateTemplateParmDecl>(Param);
+ if (TTP->isParameterPack())
+ Arg = TemplateArgument(TemplateName(TTP), Optional<unsigned>());
+ else
+ Arg = TemplateArgument(TemplateName(TTP));
+ }
+
+ if (Param->isTemplateParameterPack())
+ Arg = TemplateArgument::CreatePackCopy(*this, Arg);
+
+ return Arg;
+}
+
void
ASTContext::getInjectedTemplateArgs(const TemplateParameterList *Params,
SmallVectorImpl<TemplateArgument> &Args) {
Args.reserve(Args.size() + Params->size());
- for (NamedDecl *Param : *Params) {
- TemplateArgument Arg;
- if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
- QualType ArgType = getTypeDeclType(TTP);
- if (TTP->isParameterPack())
- ArgType = getPackExpansionType(ArgType, None);
-
- Arg = TemplateArgument(ArgType);
- } else if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
- Expr *E = new (*this) DeclRefExpr(
- NTTP, /*enclosing*/false,
- NTTP->getType().getNonLValueExprType(*this),
- Expr::getValueKindForType(NTTP->getType()), NTTP->getLocation());
-
- if (NTTP->isParameterPack())
- E = new (*this) PackExpansionExpr(DependentTy, E, NTTP->getLocation(),
- None);
- Arg = TemplateArgument(E);
- } else {
- auto *TTP = cast<TemplateTemplateParmDecl>(Param);
- if (TTP->isParameterPack())
- Arg = TemplateArgument(TemplateName(TTP), Optional<unsigned>());
- else
- Arg = TemplateArgument(TemplateName(TTP));
- }
-
- if (Param->isTemplateParameterPack())
- Arg = TemplateArgument::CreatePackCopy(*this, Arg);
-
- Args.push_back(Arg);
- }
+ for (NamedDecl *Param : *Params)
+ Args.push_back(getInjectedTemplateArg(Param));
}
QualType ASTContext::getPackExpansionType(QualType Pattern,