Variadic templates: extend Type, NestedNameSpecifier, TemplateName,
and TemplateArgument with an operation that determines whether there
are any unexpanded parameter packs within that construct. Use this
information to diagnose the appearance of the names of parameter packs
that have not been expanded (C++ [temp.variadic]p5). Since this
property is checked often (every declaration, ever expression
statement, etc.), we extend Type and Expr with a bit storing the
result of this computation, rather than walking the AST each time to
determine whether any unexpanded parameter packs occur.
This commit is deficient in several ways, which will be remedied with
future commits:
- Expr has a bit to store the presence of an unexpanded parameter
pack, but it is never set.
- The error messages don't point out where the unexpanded parameter
packs were named in the type/expression, but they should.
- We don't check for unexpanded parameter packs in all of the places
where we should.
- Testing is sparse, pending the resolution of the above three
issues.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@121724 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/NestedNameSpecifier.cpp b/lib/AST/NestedNameSpecifier.cpp
index 212def8..10035ac 100644
--- a/lib/AST/NestedNameSpecifier.cpp
+++ b/lib/AST/NestedNameSpecifier.cpp
@@ -113,6 +113,24 @@
return false;
}
+bool NestedNameSpecifier::containsUnexpandedParameterPack() const {
+ switch (getKind()) {
+ case Identifier:
+ return getPrefix() && getPrefix()->containsUnexpandedParameterPack();
+
+ case Namespace:
+ case Global:
+ return false;
+
+ case TypeSpec:
+ case TypeSpecWithTemplate:
+ return getAsType()->containsUnexpandedParameterPack();
+ }
+
+ // Necessary to suppress a GCC warning.
+ return false;
+}
+
/// \brief Print this nested name specifier to the given output
/// stream.
void