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author | Richard Smith <richard-llvm@metafoo.co.uk> | 2019-05-09 03:31:27 +0000 |
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committer | Richard Smith <richard-llvm@metafoo.co.uk> | 2019-05-09 03:31:27 +0000 |
commit | fb98e7c13da639f34f34830a4e675367e0816cb6 (patch) | |
tree | 70e025e9b4a31559d1f061e72439b5414537ad3b /lib/Parse/ParseDecl.cpp | |
parent | 70cd574857c6023b8c60e325c4029a23f716c2dd (diff) | |
download | clang-fb98e7c13da639f34f34830a4e675367e0816cb6.tar.gz |
[c++20] Implement P0846R0: allow (ADL-only) calls to template-ids whose
template name is not visible to unqualified lookup.
In order to support this without a severe degradation in our ability to
diagnose typos in template names, this change significantly restructures
the way we handle template-id-shaped syntax for which lookup of the
template name finds nothing.
Instead of eagerly diagnosing an undeclared template name, we now form a
placeholder template-name representing a name that is known to not find
any templates. When the parser sees such a name, it attempts to
disambiguate whether we have a less-than comparison or a template-id.
Any diagnostics or typo-correction for the name are delayed until its
point of use.
The upshot should be a small improvement of our diagostic quality
overall: we now take more syntactic context into account when trying to
resolve an undeclared identifier on the left hand side of a '<'. In
fact, this works well enough that the backwards-compatible portion (for
an undeclared identifier rather than a lookup that finds functions but
no function templates) is enabled in all language modes.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@360308 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Parse/ParseDecl.cpp')
-rw-r--r-- | lib/Parse/ParseDecl.cpp | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp index f5c404f7e6..9c9a9f4679 100644 --- a/lib/Parse/ParseDecl.cpp +++ b/lib/Parse/ParseDecl.cpp @@ -2916,6 +2916,7 @@ Parser::DiagnoseMissingSemiAfterTagDefinition(DeclSpec &DS, AccessSpecifier AS, case Sema::NC_Expression: case Sema::NC_VarTemplate: case Sema::NC_FunctionTemplate: + case Sema::NC_UndeclaredTemplate: // Might be a redeclaration of a prior entity. break; } @@ -3386,7 +3387,8 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS, // type-name case tok::annot_template_id: { TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok); - if (TemplateId->Kind != TNK_Type_template) { + if (TemplateId->Kind != TNK_Type_template && + TemplateId->Kind != TNK_Undeclared_template) { // This template-id does not refer to a type name, so we're // done with the type-specifiers. goto DoneWithDeclSpec; |