Author: rsmith
Date: Fri Aug 17 12:43:40 2018
New Revision: 340074
URL: http://llvm.org/viewvc/llvm-project?rev=340074&view=rev
Log:
Improve diagnostic for missing comma in template parameter list.
Given 'typename T typename U', we would correctly diagnose the missing
comma, but incorrectly disambiguate the first parameter as being a
non-type parameter and complain that the 'T' is not a qualified-id.
See also gcc.gnu.org/PR86998.
Modified:
cfe/trunk/lib/Parse/ParseTemplate.cpp
cfe/trunk/test/CXX/temp/temp.param/p2.cpp
Modified: cfe/trunk/lib/Parse/ParseTemplate.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseTemplate.cpp?rev=340074&r1=340073&r2=340074&view=diff
==============================================================================
--- cfe/trunk/lib/Parse/ParseTemplate.cpp (original)
+++ cfe/trunk/lib/Parse/ParseTemplate.cpp Fri Aug 17 12:43:40 2018
@@ -425,7 +425,9 @@ bool Parser::isStartOfTemplateTypeParame
}
}
- if (Tok.isNot(tok::kw_typename))
+ // 'typedef' is a reasonably-common typo/thinko for 'typename', and is
+ // ill-formed otherwise.
+ if (Tok.isNot(tok::kw_typename) && Tok.isNot(tok::kw_typedef))
return false;
// C++ [temp.param]p2:
@@ -448,6 +450,13 @@ bool Parser::isStartOfTemplateTypeParame
case tok::ellipsis:
return true;
+ case tok::kw_typename:
+ case tok::kw_typedef:
+ case tok::kw_class:
+ // These indicate that a comma was missed after a type parameter, not that
+ // we have found a non-type parameter.
+ return true;
+
default:
return false;
}
@@ -469,26 +478,25 @@ bool Parser::isStartOfTemplateTypeParame
/// 'template' '<' template-parameter-list '>' 'class' identifier[opt]
/// = id-expression
NamedDecl *Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) {
- if (isStartOfTemplateTypeParameter())
- return ParseTypeParameter(Depth, Position);
-
- if (Tok.is(tok::kw_template))
- return ParseTemplateTemplateParameter(Depth, Position);
+ if (isStartOfTemplateTypeParameter()) {
+ // Is there just a typo in the input code? ('typedef' instead of
'typename')
+ if (Tok.is(tok::kw_typedef)) {
+ Diag(Tok.getLocation(), diag::err_expected_template_parameter);
+
+ Diag(Tok.getLocation(), diag::note_meant_to_use_typename)
+ << FixItHint::CreateReplacement(CharSourceRange::getCharRange(
+ Tok.getLocation(),
Tok.getEndLoc()),
+ "typename");
- // Is there just a typo in the input code? ('typedef' instead of 'typename')
- if (Tok.is(tok::kw_typedef)) {
- Diag(Tok.getLocation(), diag::err_expected_template_parameter);
-
- Diag(Tok.getLocation(), diag::note_meant_to_use_typename)
- << FixItHint::CreateReplacement(CharSourceRange::getCharRange(
- Tok.getLocation(),
Tok.getEndLoc()),
- "typename");
-
- Tok.setKind(tok::kw_typename);
+ Tok.setKind(tok::kw_typename);
+ }
return ParseTypeParameter(Depth, Position);
}
+ if (Tok.is(tok::kw_template))
+ return ParseTemplateTemplateParameter(Depth, Position);
+
// If it's none of the above, then it must be a parameter declaration.
// NOTE: This will pick up errors in the closure of the template parameter
// list (e.g., template < ; Check here to implement >> style closures.
Modified: cfe/trunk/test/CXX/temp/temp.param/p2.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/temp/temp.param/p2.cpp?rev=340074&r1=340073&r2=340074&view=diff
==============================================================================
--- cfe/trunk/test/CXX/temp/temp.param/p2.cpp (original)
+++ cfe/trunk/test/CXX/temp/temp.param/p2.cpp Fri Aug 17 12:43:40 2018
@@ -8,14 +8,17 @@
template<class T> struct X;
template<typename T> struct X;
-// typename followed by aqualified-id denotes the type in a non-type
+// typename followed by a qualified-id denotes the type in a non-type
// parameter-declaration.
template<typename T, typename T::type Value> struct Y0;
template<typename T, typename X<T>::type Value> struct Y1;
+template<typename T typename U> struct Y2; // expected-error{{expected ',' or
'>'}}
+template<typename T U> struct Y3; // expected-error{{expected a qualified name
after 'typename'}} expected-error{{expected ',' or '>'}}
+template<typedef T typename U> struct Y4; // expected-error{{expected template
parameter}} expected-note {{did you mean to use 'typename'?}}
expected-error{{expected ',' or '>'}}
// A storage class shall not be specified in a template-parameter declaration.
template<static int Value> struct Z; //expected-error{{invalid declaration
specifier}}
-template<typedef int Value> struct Z0; //expected-error{{expected template
parameter}} expected-error{{expected identifier}} expected-error{{extraneous
'template<>' in declaration of struct 'Z0'}} expected-note{{did you mean to use
'typename'?}}
+template<typedef int Value> struct Z0; //expected-error{{invalid declaration
specifier}}
template<extern inline int Value> struct Z1; //expected-error2{{invalid
declaration specifier}}
template<virtual int Value> struct Z2; //expected-error{{invalid declaration
specifier}}
template<explicit int Value> struct Z3; //expected-error{{invalid declaration
specifier}}
@@ -43,6 +46,6 @@ template<auto> struct Z13; // OK
// Make sure that we properly disambiguate non-type template parameters that
// start with 'class'.
class X1 { };
-template<class X1 *xptr> struct Y2 { };
+template<class X1 *xptr> struct X2 { };
// FIXME: add the example from p2
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