PR13136:
* When substituting a reference to a non-type template parameter pack where the
corresponding argument is a pack expansion, transform into an expression
which contains an unexpanded parameter pack rather than into an expression
which contains a pack expansion. This causes the SubstNonTypeTemplateParmExpr
to be inside the PackExpansionExpr, rather than outside, so the expression
still looks like a pack expansion and can be deduced.
* Teach MarkUsedTemplateParameters that we can deduce a reference to a template
parameter if it's wrapped in a SubstNonTypeTemplateParmExpr (such nodes are
added during alias template substitution).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@159922 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index b8ec59e..60f5bc1 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -4166,9 +4166,17 @@
if (const PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(E))
E = Expansion->getPattern();
- // Skip through any implicit casts we added while type-checking.
- while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E))
- E = ICE->getSubExpr();
+ // Skip through any implicit casts we added while type-checking, and any
+ // substitutions performed by template alias expansion.
+ while (1) {
+ if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E))
+ E = ICE->getSubExpr();
+ else if (const SubstNonTypeTemplateParmExpr *Subst =
+ dyn_cast<SubstNonTypeTemplateParmExpr>(E))
+ E = Subst->getReplacement();
+ else
+ break;
+ }
// FIXME: if !OnlyDeduced, we have to walk the whole subexpression to
// find other occurrences of template parameters.