https://github.com/ilya-biryukov created
https://github.com/llvm/llvm-project/pull/99880
This addresses the FIXME in the code. There are tests for the new behavior in a
follow up fix for #99877, which also addresses other bugs that prevent exposing
the wrong results of `ContainsUnexpandedPacks` in the outputs of the compiler
without crashes.
>From 6a7422efc4badd3a84f00bc2ae161ad2ca01661c Mon Sep 17 00:00:00 2001
From: Ilya Biryukov <ibiryu...@google.com>
Date: Mon, 22 Jul 2024 15:19:07 +0200
Subject: [PATCH] [Sema] Default arguments for template parameters affect
ContainsUnexpandedPacks
This addresses the FIXME in the code. There are tests for the new
behavior in a follow up fix for #99877, which also addresses other bugs
that prevent exposing the wrong results of `ContainsUnexpandedPacks` in
the outputs of the compiler without crashes.
---
clang/lib/AST/DeclTemplate.cpp | 38 ++++++++++++++++++++++++----------
1 file changed, 27 insertions(+), 11 deletions(-)
diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
index 722c7fcf0b0df..f95be88e6c087 100644
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -61,27 +61,43 @@ TemplateParameterList::TemplateParameterList(const
ASTContext& C,
bool IsPack = P->isTemplateParameterPack();
if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
- if (!IsPack && NTTP->getType()->containsUnexpandedParameterPack())
- ContainsUnexpandedParameterPack = true;
+ if (!IsPack) {
+ if (NTTP->getType()->containsUnexpandedParameterPack())
+ ContainsUnexpandedParameterPack = true;
+ else if (NTTP->hasDefaultArgument() &&
+ NTTP->getDefaultArgument()
+ .getArgument()
+ .containsUnexpandedParameterPack())
+ ContainsUnexpandedParameterPack = true;
+ }
if (NTTP->hasPlaceholderTypeConstraint())
HasConstrainedParameters = true;
} else if (const auto *TTP = dyn_cast<TemplateTemplateParmDecl>(P)) {
- if (!IsPack &&
- TTP->getTemplateParameters()->containsUnexpandedParameterPack())
- ContainsUnexpandedParameterPack = true;
- } else if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(P)) {
- if (const TypeConstraint *TC = TTP->getTypeConstraint()) {
- if (TC->getImmediatelyDeclaredConstraint()
- ->containsUnexpandedParameterPack())
+ if (!IsPack) {
+ if (TTP->getTemplateParameters()->containsUnexpandedParameterPack())
ContainsUnexpandedParameterPack = true;
+ else if (TTP->hasDefaultArgument() &&
+ TTP->getDefaultArgument()
+ .getArgument()
+ .containsUnexpandedParameterPack())
+ ContainsUnexpandedParameterPack = true;
+ }
+ } else if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(P)) {
+ if (!IsPack && TTP->hasDefaultArgument() &&
+ TTP->getDefaultArgument()
+ .getArgument()
+ .containsUnexpandedParameterPack()) {
+ ContainsUnexpandedParameterPack = true;
+ } else if (const TypeConstraint *TC = TTP->getTypeConstraint();
+ TC && TC->getImmediatelyDeclaredConstraint()
+ ->containsUnexpandedParameterPack()) {
+ ContainsUnexpandedParameterPack = true;
}
if (TTP->hasTypeConstraint())
HasConstrainedParameters = true;
} else {
llvm_unreachable("unexpected template parameter type");
}
- // FIXME: If a default argument contains an unexpanded parameter pack, the
- // template parameter list does too.
}
if (HasRequiresClause) {
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