When a pack expansion occurs in the template argument list of an alias
template without a corresponding parameter pack, don't immediately
substitute the alias template. This is under discussion in the C++
committee, and may become ill-formed, but for now we match GCC.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149697 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 3b66932..c9af67c 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -2450,6 +2450,17 @@
Underlying);
}
+#ifndef NDEBUG
+static bool hasAnyPackExpansions(const TemplateArgument *Args,
+ unsigned NumArgs) {
+ for (unsigned I = 0; I != NumArgs; ++I)
+ if (Args[I].isPackExpansion())
+ return true;
+
+ return true;
+}
+#endif
+
QualType
ASTContext::getTemplateSpecializationType(TemplateName Template,
const TemplateArgument *Args,
@@ -2461,16 +2472,18 @@
if (QualifiedTemplateName *QTN = Template.getAsQualifiedTemplateName())
Template = TemplateName(QTN->getTemplateDecl());
- bool isTypeAlias =
+ bool IsTypeAlias =
Template.getAsTemplateDecl() &&
isa<TypeAliasTemplateDecl>(Template.getAsTemplateDecl());
-
QualType CanonType;
if (!Underlying.isNull())
CanonType = getCanonicalType(Underlying);
else {
- assert(!isTypeAlias &&
- "Underlying type for template alias must be computed by caller");
+ // We can get here with an alias template when the specialization contains
+ // a pack expansion that does not match up with a parameter pack.
+ assert((!IsTypeAlias || hasAnyPackExpansions(Args, NumArgs)) &&
+ "Caller must compute aliased type");
+ IsTypeAlias = false;
CanonType = getCanonicalTemplateSpecializationType(Template, Args,
NumArgs);
}
@@ -2480,13 +2493,11 @@
// we don't unique and don't want to lose.
void *Mem = Allocate(sizeof(TemplateSpecializationType) +
sizeof(TemplateArgument) * NumArgs +
- (isTypeAlias ? sizeof(QualType) : 0),
+ (IsTypeAlias? sizeof(QualType) : 0),
TypeAlignment);
TemplateSpecializationType *Spec
- = new (Mem) TemplateSpecializationType(Template,
- Args, NumArgs,
- CanonType,
- isTypeAlias ? Underlying : QualType());
+ = new (Mem) TemplateSpecializationType(Template, Args, NumArgs, CanonType,
+ IsTypeAlias ? Underlying : QualType());
Types.push_back(Spec);
return QualType(Spec, 0);
@@ -2498,9 +2509,6 @@
unsigned NumArgs) const {
assert(!Template.getAsDependentTemplateName() &&
"No dependent template names here!");
- assert((!Template.getAsTemplateDecl() ||
- !isa<TypeAliasTemplateDecl>(Template.getAsTemplateDecl())) &&
- "Underlying type for template alias must be computed by caller");
// Look through qualified template names.
if (QualifiedTemplateName *QTN = Template.getAsQualifiedTemplateName())
diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index 698474b..ebf5706 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -1884,7 +1884,7 @@
false,
Canon.isNull()? T.containsUnexpandedParameterPack()
: Canon->containsUnexpandedParameterPack()),
- Template(T), NumArgs(NumArgs) {
+ Template(T), NumArgs(NumArgs), TypeAlias(!AliasedType.isNull()) {
assert(!T.getAsDependentTemplateName() &&
"Use DependentTemplateSpecializationType for dependent template-name");
assert((T.getKind() == TemplateName::Template ||
@@ -1923,10 +1923,7 @@
}
// Store the aliased type if this is a type alias template specialization.
- bool IsTypeAlias = !AliasedType.isNull();
- assert(IsTypeAlias == isTypeAlias() &&
- "allocated wrong size for type alias");
- if (IsTypeAlias) {
+ if (TypeAlias) {
TemplateArgument *Begin = reinterpret_cast<TemplateArgument *>(this + 1);
*reinterpret_cast<QualType*>(Begin + getNumArgs()) = AliasedType;
}
@@ -1943,11 +1940,6 @@
Args[Idx].Profile(ID, Context);
}
-bool TemplateSpecializationType::isTypeAlias() const {
- TemplateDecl *D = Template.getAsTemplateDecl();
- return D && isa<TypeAliasTemplateDecl>(D);
-}
-
QualType
QualifierCollector::apply(const ASTContext &Context, QualType QT) const {
if (!hasNonFastQualifiers())
diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index 7cd604d..eca491f 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -1918,15 +1918,17 @@
// Check that the template argument list is well-formed for this
// template.
SmallVector<TemplateArgument, 4> Converted;
+ bool ExpansionIntoFixedList = false;
if (CheckTemplateArgumentList(Template, TemplateLoc, TemplateArgs,
- false, Converted))
+ false, Converted, &ExpansionIntoFixedList))
return QualType();
QualType CanonType;
bool InstantiationDependent = false;
- if (TypeAliasTemplateDecl *AliasTemplate
- = dyn_cast<TypeAliasTemplateDecl>(Template)) {
+ TypeAliasTemplateDecl *AliasTemplate = 0;
+ if (!ExpansionIntoFixedList &&
+ (AliasTemplate = dyn_cast<TypeAliasTemplateDecl>(Template))) {
// Find the canonical type for this type alias template specialization.
TypeAliasDecl *Pattern = AliasTemplate->getTemplatedDecl();
if (Pattern->isInvalidDecl())
@@ -2891,7 +2893,11 @@
SourceLocation TemplateLoc,
TemplateArgumentListInfo &TemplateArgs,
bool PartialTemplateArgs,
- SmallVectorImpl<TemplateArgument> &Converted) {
+ SmallVectorImpl<TemplateArgument> &Converted,
+ bool *ExpansionIntoFixedList) {
+ if (ExpansionIntoFixedList)
+ *ExpansionIntoFixedList = false;
+
TemplateParameterList *Params = Template->getTemplateParameters();
unsigned NumParams = Params->size();
unsigned NumArgs = TemplateArgs.size();
@@ -2901,7 +2907,7 @@
bool HasParameterPack =
NumParams > 0 && Params->getParam(NumParams - 1)->isTemplateParameterPack();
-
+
// C++ [temp.arg]p1:
// [...] The type and form of each template-argument specified in
// a template-id shall match the type and form specified for the
@@ -3088,6 +3094,9 @@
ArgumentPack.size()));
ArgumentPack.clear();
}
+ } else if (ExpansionIntoFixedList) {
+ // We have expanded a pack into a fixed list.
+ *ExpansionIntoFixedList = true;
}
return Invalid;