Introduce a RecursiveASTVisitor subclass that finds all unexpanded
parameter packs within a statement, type, etc. Use this visitor to
provide improved diagnostics for the presence of unexpanded parameter
packs in a full expression, base type, declaration type, etc., by
highlighting the unexpanded parameter packs and providing their names,
e.g.,
test/CXX/temp/temp.decls/temp.variadic/p5.cpp:28:85: error: declaration type
contains unexpanded parameter packs 'VeryInnerTypes',
'OuterTypes', ...
...VeryInnerTypes, OuterTypes>, pair<InnerTypes, OuterTypes> > types;
~~~~~~~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~ ^
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@121883 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaTemplateVariadic.cpp b/lib/Sema/SemaTemplateVariadic.cpp
index 42b868f..677b146 100644
--- a/lib/Sema/SemaTemplateVariadic.cpp
+++ b/lib/Sema/SemaTemplateVariadic.cpp
@@ -12,10 +12,142 @@
#include "clang/Sema/Sema.h"
#include "clang/Sema/SemaInternal.h"
#include "clang/AST/Expr.h"
+#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/TypeLoc.h"
using namespace clang;
+//----------------------------------------------------------------------------
+// Visitor that collects unexpanded parameter packs
+//----------------------------------------------------------------------------
+
+// FIXME: No way to easily map from TemplateTypeParmTypes to
+// TemplateTypeParmDecls, so we have this horrible PointerUnion.
+typedef std::pair<llvm::PointerUnion<const TemplateTypeParmType*, NamedDecl*>,
+ SourceLocation> UnexpandedParameterPack;
+
+namespace {
+ /// \brief A class that collects unexpanded parameter packs.
+ class CollectUnexpandedParameterPacksVisitor :
+ public RecursiveASTVisitor<CollectUnexpandedParameterPacksVisitor>
+ {
+ typedef RecursiveASTVisitor<CollectUnexpandedParameterPacksVisitor>
+ inherited;
+
+ llvm::SmallVectorImpl<UnexpandedParameterPack> &Unexpanded;
+
+ public:
+ explicit CollectUnexpandedParameterPacksVisitor(
+ llvm::SmallVectorImpl<UnexpandedParameterPack> &Unexpanded)
+ : Unexpanded(Unexpanded) { }
+
+ //------------------------------------------------------------------------
+ // Recording occurrences of (unexpanded) parameter packs.
+ //------------------------------------------------------------------------
+
+ /// \brief Record occurrences of template type parameter packs.
+ bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
+ if (TL.getTypePtr()->isParameterPack())
+ Unexpanded.push_back(std::make_pair(TL.getTypePtr(), TL.getNameLoc()));
+ return true;
+ }
+
+ /// \brief Record occurrences of template type parameter packs
+ /// when we don't have proper source-location information for
+ /// them.
+ ///
+ /// Ideally, this routine would never be used.
+ bool VisitTemplateTypeParmType(TemplateTypeParmType *T) {
+ if (T->isParameterPack())
+ Unexpanded.push_back(std::make_pair(T, SourceLocation()));
+
+ return true;
+ }
+
+ // FIXME: Record occurrences of non-type and template template
+ // parameter packs.
+
+ // FIXME: Once we have pack expansions in the AST, block their
+ // traversal.
+
+ //------------------------------------------------------------------------
+ // Pruning the search for unexpanded parameter packs.
+ //------------------------------------------------------------------------
+
+ /// \brief Suppress traversal into statements and expressions that
+ /// do not contain unexpanded parameter packs.
+ bool TraverseStmt(Stmt *S) {
+ if (Expr *E = dyn_cast_or_null<Expr>(S))
+ if (E->containsUnexpandedParameterPack())
+ return inherited::TraverseStmt(E);
+
+ return true;
+ }
+
+ /// \brief Suppress traversal into types that do not contain
+ /// unexpanded parameter packs.
+ bool TraverseType(QualType T) {
+ if (!T.isNull() && T->containsUnexpandedParameterPack())
+ return inherited::TraverseType(T);
+
+ return true;
+ }
+
+ /// \brief Suppress traversel into types with location information
+ /// that do not contain unexpanded parameter packs.
+ bool TraverseTypeLoc(TypeLoc TL) {
+ if (!TL.getType().isNull() && TL.
+ getType()->containsUnexpandedParameterPack())
+ return inherited::TraverseTypeLoc(TL);
+
+ return true;
+ }
+
+ /// \brief Suppress traversal of declarations, since they cannot
+ /// contain unexpanded parameter packs.
+ bool TraverseDecl(Decl *D) { return true; }
+ };
+}
+
+/// \brief Diagnose all of the unexpanded parameter packs in the given
+/// vector.
+static void
+DiagnoseUnexpandedParameterPacks(Sema &S, SourceLocation Loc,
+ Sema::UnexpandedParameterPackContext UPPC,
+ const llvm::SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
+ llvm::SmallVector<SourceLocation, 4> Locations;
+ llvm::SmallVector<IdentifierInfo *, 4> Names;
+ llvm::SmallPtrSet<IdentifierInfo *, 4> NamesKnown;
+
+ for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) {
+ IdentifierInfo *Name = 0;
+ if (const TemplateTypeParmType *TTP
+ = Unexpanded[I].first.dyn_cast<const TemplateTypeParmType *>())
+ Name = TTP->getName();
+ else
+ Name = Unexpanded[I].first.get<NamedDecl *>()->getIdentifier();
+
+ if (Name && NamesKnown.insert(Name))
+ Names.push_back(Name);
+
+ if (Unexpanded[I].second.isValid())
+ Locations.push_back(Unexpanded[I].second);
+ }
+
+ DiagnosticBuilder DB
+ = Names.size() == 0? S.Diag(Loc, diag::err_unexpanded_parameter_pack_0)
+ << (int)UPPC
+ : Names.size() == 1? S.Diag(Loc, diag::err_unexpanded_parameter_pack_1)
+ << (int)UPPC << Names[0]
+ : Names.size() == 2? S.Diag(Loc, diag::err_unexpanded_parameter_pack_2)
+ << (int)UPPC << Names[0] << Names[1]
+ : S.Diag(Loc, diag::err_unexpanded_parameter_pack_3_or_more)
+ << (int)UPPC << Names[0] << Names[1];
+
+ for (unsigned I = 0, N = Locations.size(); I != N; ++I)
+ DB << SourceRange(Locations[I]);
+}
+
bool Sema::DiagnoseUnexpandedParameterPack(SourceLocation Loc,
TypeSourceInfo *T,
UnexpandedParameterPackContext UPPC) {
@@ -25,9 +157,11 @@
if (!T->getType()->containsUnexpandedParameterPack())
return false;
- // FIXME: Provide the names and locations of the unexpanded parameter packs.
- Diag(Loc, diag::err_unexpanded_parameter_pack)
- << (int)UPPC << T->getTypeLoc().getSourceRange();
+ llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
+ CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseTypeLoc(
+ T->getTypeLoc());
+ assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs");
+ DiagnoseUnexpandedParameterPacks(*this, Loc, UPPC, Unexpanded);
return true;
}
@@ -39,8 +173,9 @@
if (!E->containsUnexpandedParameterPack())
return false;
- // FIXME: Provide the names and locations of the unexpanded parameter packs.
- Diag(E->getSourceRange().getBegin(), diag::err_unexpanded_parameter_pack)
- << (int)UPPC << E->getSourceRange();
+ llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
+ CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseStmt(E);
+ assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs");
+ DiagnoseUnexpandedParameterPacks(*this, E->getLocStart(), UPPC, Unexpanded);
return true;
}