Tweak the fix to PR8977: an empty expression-list represents value initialization, not default initialization. Fixes PR11712.

llvm-svn: 147620

2 files changed, 14 insertions, 8 deletions

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 46a47a22157..56b526b1d7e 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -8898,8 +8898,6 @@ void Sema::AddCXXDirectInitializerToDecl(Decl *RealDecl,
                                          MultiExprArg Exprs,
                                          SourceLocation RParenLoc,
                                          bool TypeMayContainAuto) {
-  assert(Exprs.size() != 0 && Exprs.get() && "missing expressions");
-
   // If there is no declaration, there was an error parsing it.  Just ignore
   // the initializer.
   if (RealDecl == 0)
@@ -8912,9 +8910,18 @@ void Sema::AddCXXDirectInitializerToDecl(Decl *RealDecl,
     return;
   }
 
-  // C++0x [decl.spec.auto]p6. Deduce the type which 'auto' stands in for.
+  // C++0x [dcl.spec.auto]p6. Deduce the type which 'auto' stands in for.
   if (TypeMayContainAuto && VDecl->getType()->getContainedAutoType()) {
-    // FIXME: n3225 doesn't actually seem to indicate this is ill-formed
+    if (Exprs.size() == 0) {
+      // It isn't possible to write this directly, but it is possible to
+      // end up in this situation with "auto x(some_pack...);"
+      Diag(LParenLoc, diag::err_auto_var_init_no_expression)
+        << VDecl->getDeclName() << VDecl->getType()
+        << VDecl->getSourceRange();
+      RealDecl->setInvalidDecl();
+      return;
+    }
+
     if (Exprs.size() > 1) {
       Diag(Exprs.get()[1]->getSourceRange().getBegin(),
            diag::err_auto_var_init_multiple_expressions)
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 1f879838052..00addc2d83f 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -393,16 +393,15 @@ Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
     if (!SemaRef.InstantiateInitializer(D->getInit(), TemplateArgs, LParenLoc,
                                         InitArgs, RParenLoc)) {
       bool TypeMayContainAuto = true;
-      // Attach the initializer to the declaration, if we have one.
-      if (InitArgs.size() == 0)
-        SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
-      else if (D->hasCXXDirectInitializer()) {
+      if (D->hasCXXDirectInitializer()) {
         // Add the direct initializer to the declaration.
         SemaRef.AddCXXDirectInitializerToDecl(Var,
                                               LParenLoc,
                                               move_arg(InitArgs),
                                               RParenLoc,
                                               TypeMayContainAuto);
+      } else if (InitArgs.size() == 0) {
+        SemaRef.ActOnUninitializedDecl(Var, TypeMayContainAuto);
       } else {
         assert(InitArgs.size() == 1);
         Expr *Init = InitArgs.take()[0];