Hi rsmith,
While testing one of my previous patches, I tried to explicitly instantiate an
alias template with class-key (so that declaration seems like to include an
elaborated-type-specifier) and expected a syntax error, but clang crashed. I
have talked with Richard in Bristol, and he mentioned he's already heard about
a similar crash but I couldn't find it in Bugzilla.
The issue that this patch addresses (i.e. ill-formed elaborated-type-specifier)
seems like a syntax error that maybe handled in the parser, but this patch
handles it in Sema (because it was easier to access necessary parameters).
temp.explicit/p2-3 describes the syntax and requirements for explicit
instantiation.
p3:"If the explicit instantiation is for a class or member class, the
elaborated-type-specifier in the declaration shall include a
simple-template-id. [...]"
dcl.type.elab/p2:
[...]If the identifier resolves to a typedef-name or the simple-template-id
resolves to an alias template specialization, the elaborated-type-specifier is
ill-formed.[...]
We should refuse explicit instantiation because elaborated-type-specifier will
be ill-formed.
http://llvm-reviews.chandlerc.com/D868
Files:
lib/Sema/SemaTemplate.cpp
test/SemaCXX/using-decl-templates.cpp
Index: lib/Sema/SemaTemplate.cpp
===================================================================
--- lib/Sema/SemaTemplate.cpp
+++ lib/Sema/SemaTemplate.cpp
@@ -6341,14 +6341,22 @@
AttributeList *Attr) {
// Find the class template we're specializing
TemplateName Name = TemplateD.getAsVal<TemplateName>();
- ClassTemplateDecl *ClassTemplate
- = cast<ClassTemplateDecl>(Name.getAsTemplateDecl());
-
+ TemplateDecl *TD = Name.getAsTemplateDecl();
// Check that the specialization uses the same tag kind as the
// original template.
TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
assert(Kind != TTK_Enum &&
"Invalid enum tag in class template explicit instantiation!");
+
+ if (isa<TypeAliasTemplateDecl>(TD)) {
+ Diag(KWLoc, diag::err_tag_reference_non_tag) << Kind;
+ Diag(TD->getTemplatedDecl()->getLocation(),
+ diag::note_previous_use);
+ return true;
+ }
+
+ ClassTemplateDecl *ClassTemplate = cast<ClassTemplateDecl>(TD);
+
if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
Kind, /*isDefinition*/false, KWLoc,
*ClassTemplate->getIdentifier())) {
Index: test/SemaCXX/using-decl-templates.cpp
===================================================================
--- test/SemaCXX/using-decl-templates.cpp
+++ test/SemaCXX/using-decl-templates.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
template<typename T> struct A {
void f() { }
@@ -80,3 +80,10 @@
void foo(const Container& current); // expected-error {{unknown type name
'Container'}}
};
}
+
+namespace aliastemplateinst {
+ template<typename T> struct A { };
+ template<typename T> using APtr = A<T*>; // expected-note{{previous use is
here}}
+
+ template struct APtr<int>; // expected-error{{elaborated type refers to a
non-tag type}}
+}
Index: lib/Sema/SemaTemplate.cpp
===================================================================
--- lib/Sema/SemaTemplate.cpp
+++ lib/Sema/SemaTemplate.cpp
@@ -6341,14 +6341,22 @@
AttributeList *Attr) {
// Find the class template we're specializing
TemplateName Name = TemplateD.getAsVal<TemplateName>();
- ClassTemplateDecl *ClassTemplate
- = cast<ClassTemplateDecl>(Name.getAsTemplateDecl());
-
+ TemplateDecl *TD = Name.getAsTemplateDecl();
// Check that the specialization uses the same tag kind as the
// original template.
TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
assert(Kind != TTK_Enum &&
"Invalid enum tag in class template explicit instantiation!");
+
+ if (isa<TypeAliasTemplateDecl>(TD)) {
+ Diag(KWLoc, diag::err_tag_reference_non_tag) << Kind;
+ Diag(TD->getTemplatedDecl()->getLocation(),
+ diag::note_previous_use);
+ return true;
+ }
+
+ ClassTemplateDecl *ClassTemplate = cast<ClassTemplateDecl>(TD);
+
if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
Kind, /*isDefinition*/false, KWLoc,
*ClassTemplate->getIdentifier())) {
Index: test/SemaCXX/using-decl-templates.cpp
===================================================================
--- test/SemaCXX/using-decl-templates.cpp
+++ test/SemaCXX/using-decl-templates.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
template<typename T> struct A {
void f() { }
@@ -80,3 +80,10 @@
void foo(const Container& current); // expected-error {{unknown type name 'Container'}}
};
}
+
+namespace aliastemplateinst {
+ template<typename T> struct A { };
+ template<typename T> using APtr = A<T*>; // expected-note{{previous use is here}}
+
+ template struct APtr<int>; // expected-error{{elaborated type refers to a non-tag type}}
+}
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