PR13243: When deducing a non-type template parameter which is specified as an
expression, skip over any SubstNonTypeTemplateParmExprs which alias templates
may have inserted before checking for a DeclRefExpr referring to a non-type
template parameter declaration.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@159909 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index 310d9b3..b8ec59e 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -137,8 +137,17 @@
/// of a non-type template parameter, return the declaration of that
/// non-type template parameter.
static NonTypeTemplateParmDecl *getDeducedParameterFromExpr(Expr *E) {
- if (ImplicitCastExpr *IC = dyn_cast<ImplicitCastExpr>(E))
- E = IC->getSubExpr();
+ // If we are within an alias template, the expression may have undergone
+ // any number of parameter substitutions already.
+ while (1) {
+ if (ImplicitCastExpr *IC = dyn_cast<ImplicitCastExpr>(E))
+ E = IC->getSubExpr();
+ else if (SubstNonTypeTemplateParmExpr *Subst =
+ dyn_cast<SubstNonTypeTemplateParmExpr>(E))
+ E = Subst->getReplacement();
+ else
+ break;
+ }
if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
return dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());