[COMMITTED 056/141] gccrs: Fix crash in privay reporter for placeholder types

[arthur.cohen@embecosm.com]

From: Philip Herron <herron.philip@googlemail.com>

This guards against a crash but i think this should actually be treated
as if its a generic type like below. But for now this addresses a crash which can occur.

gcc/rust/ChangeLog:

	* checks/errors/privacy/rust-privacy-reporter.cc (PrivacyReporter::check_base_type_privacy):
	Add guard for placeholder

Signed-off-by: Philip Herron <herron.philip@googlemail.com>
---
 .../checks/errors/privacy/rust-privacy-reporter.cc     | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/gcc/rust/checks/errors/privacy/rust-privacy-reporter.cc b/gcc/rust/checks/errors/privacy/rust-privacy-reporter.cc
index dcc768ffff1..896c1c449ab 100644
--- a/gcc/rust/checks/errors/privacy/rust-privacy-reporter.cc
+++ b/gcc/rust/checks/errors/privacy/rust-privacy-reporter.cc
@@ -243,10 +243,12 @@ PrivacyReporter::check_base_type_privacy (Analysis::NodeMapping &node_mappings,
 	   static_cast<const TyTy::TupleType *> (ty)->get_fields ())
 	recursive_check (param.get_tyty ());
       return;
-    case TyTy::PLACEHOLDER:
-      return recursive_check (
-	// FIXME: Can we use `resolve` here? Is that what we should do?
-	static_cast<const TyTy::PlaceholderType *> (ty)->resolve ());
+      case TyTy::PLACEHOLDER: {
+	const auto p = static_cast<const TyTy::PlaceholderType *> (ty);
+	if (!p->can_resolve ())
+	  return;
+	return recursive_check (p->resolve ());
+      }
     case TyTy::PROJECTION:
       return recursive_check (
 	static_cast<const TyTy::ProjectionType *> (ty)->get ());
-- 
2.45.2