Implement support for pack expansions whose pattern is a non-type
template argument (described by an expression, of course). For
example:
template<int...> struct int_tuple { };
template<int ...Values>
struct square {
typedef int_tuple<(Values*Values)...> type;
};
It also lays the foundation for pack expansions in an initializer-list.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@122751 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaTemplateVariadic.cpp b/lib/Sema/SemaTemplateVariadic.cpp
index 3dac8a0..030a042 100644
--- a/lib/Sema/SemaTemplateVariadic.cpp
+++ b/lib/Sema/SemaTemplateVariadic.cpp
@@ -79,9 +79,6 @@
// FIXME: Record occurrences of template template parameter packs.
- // FIXME: Once we have pack expansions in the AST, block their
- // traversal.
-
//------------------------------------------------------------------------
// Pruning the search for unexpanded parameter packs.
//------------------------------------------------------------------------
@@ -299,14 +296,17 @@
Arg.getLocation());
}
- case ParsedTemplateArgument::NonType:
- Diag(EllipsisLoc, diag::err_pack_expansion_unsupported)
- << 0;
- return ParsedTemplateArgument();
-
+ case ParsedTemplateArgument::NonType: {
+ ExprResult Result = ActOnPackExpansion(Arg.getAsExpr(), EllipsisLoc);
+ if (Result.isInvalid())
+ return ParsedTemplateArgument();
+
+ return ParsedTemplateArgument(Arg.getKind(), Result.get(),
+ Arg.getLocation());
+ }
+
case ParsedTemplateArgument::Template:
- Diag(EllipsisLoc, diag::err_pack_expansion_unsupported)
- << 1;
+ Diag(EllipsisLoc, diag::err_pack_expansion_unsupported);
return ParsedTemplateArgument();
}
llvm_unreachable("Unhandled template argument kind?");
@@ -352,6 +352,24 @@
return TSResult;
}
+ExprResult Sema::ActOnPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc) {
+ if (!Pattern)
+ return ExprError();
+
+ // C++0x [temp.variadic]p5:
+ // The pattern of a pack expansion shall name one or more
+ // parameter packs that are not expanded by a nested pack
+ // expansion.
+ if (!Pattern->containsUnexpandedParameterPack()) {
+ Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
+ << Pattern->getSourceRange();
+ return ExprError();
+ }
+
+ // Create the pack expansion expression and source-location information.
+ return Owned(new (Context) PackExpansionExpr(Context.DependentTy, Pattern,
+ EllipsisLoc));
+}
bool Sema::CheckParameterPacksForExpansion(SourceLocation EllipsisLoc,
SourceRange PatternRange,