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When a function template's template parameter has a default argument, 

it's okay for the following template parameters to not have default
arguments (since those template parameters can still be
deduced). Also, downgrade the error about default template arguments
in function templates to an extension warning, since this is a
harmless C++0x extension.

llvm-svn: 124855
This commit is contained in:
Douglas Gregor 2011-02-04 03:57:22 +00:00
parent a6aa87898b
commit 8b481d8ac2
4 changed files with 20 additions and 7 deletions
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6
clang/include/clang/Basic/DiagnosticSemaKinds.td
View File

@ -1476,9 +1476,9 @@ def note_template_param_prev_default_arg : Note<
"previous default template argument defined here">;
def err_template_param_default_arg_missing : Error<
"template parameter missing a default argument">;
def err_template_parameter_default_in_function_template : Error<
"a template parameter of a function template cannot have a default argument "
"in C++98">;
def ext_template_parameter_default_in_function_template : ExtWarn<
"default template arguments for a function template are a C++0x extension">,
InGroup<CXX0x>;
def err_template_parameter_default_template_member : Error<
"cannot add a default template argument to the definition of a member of a "
"class template">;

4
clang/lib/Sema/SemaTemplate.cpp
View File

@ -1052,7 +1052,7 @@ static bool DiagnoseDefaultTemplateArgument(Sema &S,
// (This sentence is not in C++0x, per DR226).
if (!S.getLangOptions().CPlusPlus0x)
S.Diag(ParamLoc,
diag::err_template_parameter_default_in_function_template)
diag::ext_template_parameter_default_in_function_template)
<< DefArgRange;
return false;
@ -1315,7 +1315,7 @@ bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
Diag(NewDefaultLoc, diag::err_template_param_default_arg_redefinition);
Diag(OldDefaultLoc, diag::note_template_param_prev_default_arg);
Invalid = true;
} else if (MissingDefaultArg) {
} else if (MissingDefaultArg && TPC != TPC_FunctionTemplate) {
// C++ [temp.param]p11:
// If a template-parameter of a class template has a default
// template-argument, each subsequent template-parameter shall either

13
clang/test/CXX/temp/temp.param/p11-0x.cpp
View File

@ -46,3 +46,16 @@ void f1nt(X1nt<V, Values...>);
template<template<int> class... Meta, template<int> class M>
void f1tt(X1tt<M, Meta...>);
namespace DefaultTemplateArgsInFunction {
template<typename T = int, typename U> T &f0(U) { T *x = 0; return *x; }
void test_f0() {
int &ir0 = f0(3.14159);
int &ir1 = f0<int>(3.14159);
float &fr0 = f0<float>(3.14159);
}
template<> int &f0(int*);
template int &f0(double&);
}

4
clang/test/CXX/temp/temp.param/p9.cpp
View File

@ -2,9 +2,9 @@
// A default template-argument shall not be specified in a function
// template declaration or a function template definition
template<typename T = int> // expected-error{{cannot have a default argument}}
template<typename T = int> // expected-warning{{default template arguments for a function template are a C++0x extension}}
void foo0(T);
template<typename T = int> // expected-error{{cannot have a default argument}}
template<typename T = int> // expected-warning{{default template arguments for a function template are a C++0x extension}}
void foo1(T) { }
// [...] nor in the template-parameter-list of the definition of a