Re: [PATCH] c++: ICE with -Wshadow and enumerator in template [PR99120]

[Jason Merrill via Gcc-patches]

On 3/5/21 11:44 AM, Marek Polacek wrote:

We crash here, because in a template, an enumerator doesn't have
a type until we've called finish_enum_value_list.  But our -Wshadow
implementation, check_local_shadow, is called when we pushdecl in
build_enumerator, which takes place before finish_enum_value_list.

Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/10?

OK.

gcc/cp/ChangeLog:

        PR c++/99120
        * name-lookup.c (check_local_shadow): Check if the type of decl
        is non-null before checking TYPE_PTR*.

gcc/testsuite/ChangeLog:

        PR c++/99120
        * g++.dg/warn/Wshadow-17.C: New test.
---
  gcc/cp/name-lookup.c                   |  7 ++++---
  gcc/testsuite/g++.dg/warn/Wshadow-17.C | 11 +++++++++++
  2 files changed, 15 insertions(+), 3 deletions(-)
  create mode 100644 gcc/testsuite/g++.dg/warn/Wshadow-17.C

diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index f57708700c2..092fa6b8768 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -3309,7 +3309,7 @@ check_local_shadow (tree decl)
    /* Don't warn for artificial things that are not implicit typedefs.  */
    if (DECL_ARTIFICIAL (decl) && !DECL_IMPLICIT_TYPEDEF_P (decl))
      return;
-
+
    if (nonlambda_method_basetype ())
      if (tree member = lookup_member (current_nonlambda_class_type (),
                                     DECL_NAME (decl), /*protect=*/0,
@@ -3321,8 +3321,9 @@ check_local_shadow (tree decl)
           is a function or a pointer-to-function.  */
        if (!OVL_P (member)
            || TREE_CODE (decl) == FUNCTION_DECL
-           || TYPE_PTRFN_P (TREE_TYPE (decl))
-           || TYPE_PTRMEMFUNC_P (TREE_TYPE (decl)))
+           || (TREE_TYPE (decl)
+               && (TYPE_PTRFN_P (TREE_TYPE (decl))
+                   || TYPE_PTRMEMFUNC_P (TREE_TYPE (decl)))))
          {
            auto_diagnostic_group d;
            if (warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wshadow,
diff --git a/gcc/testsuite/g++.dg/warn/Wshadow-17.C 
b/gcc/testsuite/g++.dg/warn/Wshadow-17.C
new file mode 100644
index 00000000000..0dee397796f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wshadow-17.C
@@ -0,0 +1,11 @@
+// PR c++/99120
+// { dg-options "-Wshadow" }
+
+struct S {
+  void X();
+
+  template<typename T>
+  void fn () {
+    enum { X };
+  }
+};

base-commit: 4d66685e49d20e0c7a87c5fa0757c7eb63ffcdaa