[llvm-branch-commits] [clang] 02dece0 - [clang] fix transformation of template arguments of 'auto' type constraints

[Tom Stellard via llvm-branch-commits]

Author: Matheus Izvekov
Date: 2021-09-08T14:09:00-07:00
New Revision: 02dece03f93d2ff847c3867e5f655793e29b2877

URL: https://github.com/llvm/llvm-project/commit/02dece03f93d2ff847c3867e5f655793e29b2877
DIFF: https://github.com/llvm/llvm-project/commit/02dece03f93d2ff847c3867e5f655793e29b2877.diff

LOG: [clang] fix transformation of template arguments of 'auto' type constraints

See PR48617.

When assigning the new template arguments to the new TypeLoc, we were looping
on the argument count of the original TypeLoc instead of the new one,
which can be different when packs are present.

Signed-off-by: Matheus Izvekov <mizvekov at gmail.com>

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D109406

(cherry picked from commit 68b9d8ed7abe4046992ae1557990edfbb3a772bc)

Added: 
    

Modified: 
    clang/lib/Sema/TreeTransform.h
    clang/test/CXX/dcl/dcl.spec/dcl.type/dcl.spec.auto/p6.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 70ba631dbfc6..d8a5b6ad4f94 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -6578,7 +6578,7 @@ QualType TreeTransform<Derived>::TransformAutoType(TypeLocBuilder &TLB,
   NewTL.setFoundDecl(TL.getFoundDecl());
   NewTL.setLAngleLoc(TL.getLAngleLoc());
   NewTL.setRAngleLoc(TL.getRAngleLoc());
-  for (unsigned I = 0; I < TL.getNumArgs(); ++I)
+  for (unsigned I = 0; I < NewTL.getNumArgs(); ++I)
     NewTL.setArgLocInfo(I, NewTemplateArgs.arguments()[I].getLocInfo());
 
   return Result;

diff  --git a/clang/test/CXX/dcl/dcl.spec/dcl.type/dcl.spec.auto/p6.cpp b/clang/test/CXX/dcl/dcl.spec/dcl.type/dcl.spec.auto/p6.cpp
index 7830d1f43526..494102742321 100644
--- a/clang/test/CXX/dcl/dcl.spec/dcl.type/dcl.spec.auto/p6.cpp
+++ b/clang/test/CXX/dcl/dcl.spec/dcl.type/dcl.spec.auto/p6.cpp
@@ -76,3 +76,25 @@ namespace PR48593 {
   template<class> concept d = true;
   d<,> auto e = 0; // expected-error{{expected expression}}
 }
+
+namespace PR48617 {
+  template <typename...> concept C = true;
+  template <typename...> class A {};
+
+  template <typename... Ts> C<Ts...> auto e(A<Ts...>) { return 0; }
+
+  // FIXME: The error here does not make sense.
+  template auto e<>(A<>);
+  // expected-error at -1 {{explicit instantiation of 'e' does not refer to a function template}}
+  // expected-note at -5  {{candidate template ignored: failed template argument deduction}}
+
+  // FIXME: Should be able to instantiate this with no errors.
+  template C<int> auto e<int>(A<int>);
+  // expected-error at -1 {{explicit instantiation of 'e' does not refer to a function template}}
+  // expected-note at -10 {{candidate template ignored: could not match 'C<int, Ts...> auto' against 'C<int> auto'}}
+  
+  template C<> auto e<>(A<>);
+
+  template <typename... Ts> A<Ts...> c(Ts...);
+  int f = e(c(1, 2));
+}