gccrs: Make coercion sites autoderef cycle optional

Signed-off-by: Philip Herron <herron.philip@googlemail.com>

gcc/rust/ChangeLog:

	* typecheck/rust-casts.cc (TypeCastRules::check): update to new interface
	* typecheck/rust-coercion.cc (TypeCoercionRules::Coerce): likewise
	(TypeCoercionRules::TryCoerce): likewise
	(TypeCoercionRules::TypeCoercionRules): likewise
	* typecheck/rust-coercion.h: likewise
	* typecheck/rust-type-util.cc (coercion_site): likewise

4 files changed, 17 insertions, 12 deletions

diff --git a/gcc/rust/typecheck/rust-casts.cc b/gcc/rust/typecheck/rust-casts.cc
index 987542e..0ecb50f 100644
--- a/gcc/rust/typecheck/rust-casts.cc
+++ b/gcc/rust/typecheck/rust-casts.cc
@@ -39,7 +39,8 @@ TypeCastRules::check ()
 {
   // https://github.com/rust-lang/rust/blob/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/compiler/rustc_typeck/src/check/cast.rs#L565-L582
   auto possible_coercion
-    = TypeCoercionRules::TryCoerce (from.get_ty (), to.get_ty (), locus);
+    = TypeCoercionRules::TryCoerce (from.get_ty (), to.get_ty (), locus,
+				    true /*allow-autoderef*/);
   if (!possible_coercion.is_error ())
     return possible_coercion;
 
diff --git a/gcc/rust/typecheck/rust-coercion.cc b/gcc/rust/typecheck/rust-coercion.cc
index fdc8bdd..7a3f51a 100644
--- a/gcc/rust/typecheck/rust-coercion.cc
+++ b/gcc/rust/typecheck/rust-coercion.cc
@@ -25,25 +25,26 @@ namespace Resolver {
 
 TypeCoercionRules::CoercionResult
 TypeCoercionRules::Coerce (TyTy::BaseType *receiver, TyTy::BaseType *expected,
-			   Location locus)
+			   Location locus, bool allow_autoderef)
 {
-  TypeCoercionRules resolver (expected, locus, true);
+  TypeCoercionRules resolver (expected, locus, true, allow_autoderef);
   bool ok = resolver.do_coercion (receiver);
   return ok ? resolver.try_result : CoercionResult::get_error ();
 }
 
 TypeCoercionRules::CoercionResult
 TypeCoercionRules::TryCoerce (TyTy::BaseType *receiver,
-			      TyTy::BaseType *expected, Location locus)
+			      TyTy::BaseType *expected, Location locus,
+			      bool allow_autoderef)
 {
-  TypeCoercionRules resolver (expected, locus, false);
+  TypeCoercionRules resolver (expected, locus, false, allow_autoderef);
   bool ok = resolver.do_coercion (receiver);
   return ok ? resolver.try_result : CoercionResult::get_error ();
 }
 
 TypeCoercionRules::TypeCoercionRules (TyTy::BaseType *expected, Location locus,
-				      bool emit_errors)
-  : AutoderefCycle (false), mappings (Analysis::Mappings::get ()),
+				      bool emit_errors, bool allow_autoderef)
+  : AutoderefCycle (!allow_autoderef), mappings (Analysis::Mappings::get ()),
     context (TypeCheckContext::get ()), expected (expected), locus (locus),
     try_result (CoercionResult::get_error ()), emit_errors (emit_errors)
 {}
diff --git a/gcc/rust/typecheck/rust-coercion.h b/gcc/rust/typecheck/rust-coercion.h
index d0fc0f9..69442e5 100644
--- a/gcc/rust/typecheck/rust-coercion.h
+++ b/gcc/rust/typecheck/rust-coercion.h
@@ -42,10 +42,12 @@ public:
   };
 
   static CoercionResult Coerce (TyTy::BaseType *receiver,
-				TyTy::BaseType *expected, Location locus);
+				TyTy::BaseType *expected, Location locus,
+				bool allow_autoderef);
 
   static CoercionResult TryCoerce (TyTy::BaseType *receiver,
-				   TyTy::BaseType *expected, Location locus);
+				   TyTy::BaseType *expected, Location locus,
+				   bool allow_autoderef);
 
   CoercionResult coerce_unsafe_ptr (TyTy::BaseType *receiver,
 				    TyTy::PointerType *expected,
@@ -66,8 +68,8 @@ public:
   void object_unsafe_error (Location expr_locus, Location lhs, Location rhs);
 
 protected:
-  TypeCoercionRules (TyTy::BaseType *expected, Location locus,
-		     bool emit_errors);
+  TypeCoercionRules (TyTy::BaseType *expected, Location locus, bool emit_errors,
+		     bool allow_autoderef);
 
   bool select (const TyTy::BaseType &autoderefed) override;
 
diff --git a/gcc/rust/typecheck/rust-type-util.cc b/gcc/rust/typecheck/rust-type-util.cc
index ff7c805..da9a724 100644
--- a/gcc/rust/typecheck/rust-type-util.cc
+++ b/gcc/rust/typecheck/rust-type-util.cc
@@ -186,7 +186,8 @@ coercion_site (HirId id, TyTy::TyWithLocation lhs, TyTy::TyWithLocation rhs,
     return expr;
 
   // can we autoderef it?
-  auto result = TypeCoercionRules::Coerce (expr, expected, locus);
+  auto result = TypeCoercionRules::Coerce (expr, expected, locus,
+					   true /*allow-autodref*/);
 
   // the result needs to be unified
   TyTy::BaseType *receiver = expr;