Diagnose missing 'template' keywords in more cases.
We track when we see a name-shaped expression followed by a '<' token
and parse the '<' as a comparison. Then:
* if we see a token sequence that cannot possibly be an expression but
can be a template argument (in particular, a type-id) that follows
either a ',' or the '<', diagnose that the '<' was supposed to start
a template argument list, and
* if we see '>()', diagnose that the '<' was supposed to start a
template argument list.
This only changes the diagnostic for error cases, and in practice
appears to catch the most common cases where a missing 'template'
keyword leads to parse errors within a template.
Differential Revision: https://reviews.llvm.org/D48571
llvm-svn: 335687
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 8f31602..68a5196 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -508,20 +508,41 @@
DeclContext *LookupCtx = nullptr;
NamedDecl *Found = nullptr;
+ bool MissingTemplateKeyword = false;
// Figure out what name we looked up.
- if (auto *ME = dyn_cast<MemberExpr>(TemplateName.get())) {
+ if (auto *DRE = dyn_cast<DeclRefExpr>(TemplateName.get())) {
+ NameInfo = DRE->getNameInfo();
+ SS.Adopt(DRE->getQualifierLoc());
+ LookupKind = LookupOrdinaryName;
+ Found = DRE->getFoundDecl();
+ } else if (auto *ME = dyn_cast<MemberExpr>(TemplateName.get())) {
NameInfo = ME->getMemberNameInfo();
SS.Adopt(ME->getQualifierLoc());
LookupKind = LookupMemberName;
LookupCtx = ME->getBase()->getType()->getAsCXXRecordDecl();
Found = ME->getMemberDecl();
+ } else if (auto *DSDRE =
+ dyn_cast<DependentScopeDeclRefExpr>(TemplateName.get())) {
+ NameInfo = DSDRE->getNameInfo();
+ SS.Adopt(DSDRE->getQualifierLoc());
+ MissingTemplateKeyword = true;
+ } else if (auto *DSME =
+ dyn_cast<CXXDependentScopeMemberExpr>(TemplateName.get())) {
+ NameInfo = DSME->getMemberNameInfo();
+ SS.Adopt(DSME->getQualifierLoc());
+ MissingTemplateKeyword = true;
} else {
- auto *DRE = cast<DeclRefExpr>(TemplateName.get());
- NameInfo = DRE->getNameInfo();
- SS.Adopt(DRE->getQualifierLoc());
- LookupKind = LookupOrdinaryName;
- Found = DRE->getFoundDecl();
+ llvm_unreachable("unexpected kind of potential template name");
+ }
+
+ // If this is a dependent-scope lookup, diagnose that the 'template' keyword
+ // was missing.
+ if (MissingTemplateKeyword) {
+ Diag(NameInfo.getLocStart(), diag::err_template_kw_missing)
+ << "" << NameInfo.getName().getAsString()
+ << SourceRange(Less, Greater);
+ return;
}
// Try to correct the name by looking for templates and C++ named casts.