3 files changed, 31 insertions, 1 deletions
diff --git a/clang/include/clang/Basic/DiagnosticASTKinds.td b/clang/include/clang/Basic/DiagnosticASTKinds.td
index eb2a1f02fd8..f4eeebd73ab 100644
--- a/clang/include/clang/Basic/DiagnosticASTKinds.td
+++ b/clang/include/clang/Basic/DiagnosticASTKinds.td
@@ -210,6 +210,9 @@ def note_constexpr_destroy_out_of_lifetime : Note<
   "destroying object '%0' whose lifetime has already ended">;
 def note_constexpr_unsupported_destruction : Note<
   "non-trivial destruction of type %0 in a constant expression is not supported">;
+def note_constexpr_unsupported_tempoarary_nontrivial_dtor : Note<
+  "non-trivial destruction of lifetime-extended temporary with type %0 "
+  "used in the result of a constant expression is not yet supported">;
 def note_constexpr_unsupported_unsized_array : Note<
   "array-to-pointer decay of array member without known bound is not supported">;
 def note_constexpr_unsized_array_indexed : Note<
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index b0c0c2e8d98..f91e0782b89 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -1999,10 +1999,18 @@ static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
   } else if (const auto *MTE = dyn_cast_or_null<MaterializeTemporaryExpr>(
                  Base.dyn_cast<const Expr *>())) {
     if (CheckedTemps.insert(MTE).second) {
+      QualType TempType = getType(Base);
+      if (TempType.isDestructedType()) {
+        Info.FFDiag(MTE->getExprLoc(),
+                    diag::note_constexpr_unsupported_tempoarary_nontrivial_dtor)
+            << TempType;
+        return false;
+      }
+
       APValue *V = Info.Ctx.getMaterializedTemporaryValue(MTE, false);
       assert(V && "evasluation result refers to uninitialised temporary");
       if (!CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression,
-                                 Info, MTE->getExprLoc(), getType(Base), *V,
+                                 Info, MTE->getExprLoc(), TempType, *V,
                                  Usage, SourceLocation(), CheckedTemps))
         return false;
     }
diff --git a/clang/test/SemaCXX/constant-expression-cxx2a.cpp b/clang/test/SemaCXX/constant-expression-cxx2a.cpp
index 152bfcf0a7b..5e05c292984 100644
--- a/clang/test/SemaCXX/constant-expression-cxx2a.cpp
+++ b/clang/test/SemaCXX/constant-expression-cxx2a.cpp
@@ -1250,3 +1250,22 @@ namespace dtor_call {
     as.b.~A(); // expected-note {{destruction of member 'b' of union with active member 'a'}}
   }
 }
+
+namespace temp_dtor {
+  void f();
+  struct A {
+    bool b;
+    constexpr ~A() { if (b) f(); }
+  };
+
+  // We can't accept either of these unless we start actually registering the
+  // destructors of the A temporaries to run on shutdown. It's unclear what the
+  // intended standard behavior is so we reject this for now.
+  constexpr A &&a = A{false}; // expected-error {{constant}} expected-note {{non-trivial destruction of lifetime-extended temporary}}
+  void f() { a.b = true; }
+
+  constexpr A &&b = A{true}; // expected-error {{constant}} expected-note {{non-trivial destruction of lifetime-extended temporary}}
+
+  // FIXME: We could in prinicple accept this.
+  constexpr const A &c = A{false}; // expected-error {{constant}} expected-note {{non-trivial destruction of lifetime-extended temporary}}
+}