Implement instantiation of pack expansions whose pattern is a type-id

in an exception specification.

llvm-svn: 122297

1 files changed, 55 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index b6ef498874e..115cdc45451 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1983,6 +1983,61 @@ TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
     llvm::SmallVector<QualType, 4> Exceptions;
     for (unsigned I = 0, N = Proto->getNumExceptions(); I != N; ++I) {
       // FIXME: Poor location information!
+      if (const PackExpansionType *PackExpansion
+            = Proto->getExceptionType(I)->getAs<PackExpansionType>()) {
+        // We have a pack expansion. Instantiate it.
+        llvm::SmallVector<UnexpandedParameterPack, 2> Unexpanded;
+        SemaRef.collectUnexpandedParameterPacks(PackExpansion->getPattern(),
+                                                Unexpanded);
+        assert(!Unexpanded.empty() && 
+               "Pack expansion without parameter packs?");
+        
+        bool Expand = false;
+        unsigned NumExpansions = 0;
+        if (SemaRef.CheckParameterPacksForExpansion(New->getLocation(), 
+                                                    SourceRange(),
+                                                    Unexpanded.data(), 
+                                                    Unexpanded.size(),
+                                                    TemplateArgs,
+                                                    Expand, NumExpansions))
+          break;
+                      
+        if (!Expand) {
+          // We can't expand this pack expansion into separate arguments yet;
+          // just substitute into the argument pack.
+          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, -1);
+          QualType T = SemaRef.SubstType(PackExpansion->getPattern(), 
+                                         TemplateArgs,
+                                       New->getLocation(), New->getDeclName());
+          if (T.isNull())
+            break;
+          
+          Exceptions.push_back(T);
+          continue;
+        }
+        
+        // Substitute into the pack expansion pattern for each template
+        bool Invalid = false;
+        for (unsigned ArgIdx = 0; ArgIdx != NumExpansions; ++ArgIdx) {
+          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, ArgIdx);
+          
+          QualType T = SemaRef.SubstType(PackExpansion->getPattern(), 
+                                         TemplateArgs,
+                                       New->getLocation(), New->getDeclName());
+          if (T.isNull()) {
+            Invalid = true;
+            break;
+          }
+          
+          Exceptions.push_back(T);
+        }
+        
+        if (Invalid)
+          break;
+        
+        continue;
+      }
+      
       QualType T
         = SemaRef.SubstType(Proto->getExceptionType(I), TemplateArgs,
                             New->getLocation(), New->getDeclName());