[gcc r14-8601] gccrs: TyTy: SubstitutionRef cast specialization

[Arthur Cohen]

https://gcc.gnu.org/g:75e6d0cf415c939b020cef2e2693b652848ae45d

commit r14-8601-g75e6d0cf415c939b020cef2e2693b652848ae45d
Author: Jakub Dupak <dev@jakubdupak.com>
Date:   Mon Dec 11 23:11:34 2023 +0100

    gccrs: TyTy: SubstitutionRef cast specialization
    
    Allows skipping parent check when casting.
    
    gcc/rust/ChangeLog:
    
            * typecheck/rust-tyty.h (BaseType::is): Cast API.
            (SubstitutionRef>): Cast API.
            (BaseType::as): Cast API.
            (BaseType::try_as): Cast API.
    
    Signed-off-by: Jakub Dupak <dev@jakubdupak.com>

Diff:
---
 gcc/rust/typecheck/rust-tyty.h | 78 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)

diff --git a/gcc/rust/typecheck/rust-tyty.h b/gcc/rust/typecheck/rust-tyty.h
index 6ce760df66e6..2ed407ee169b 100644
--- a/gcc/rust/typecheck/rust-tyty.h
+++ b/gcc/rust/typecheck/rust-tyty.h
@@ -1575,6 +1575,84 @@ BaseType::is<const CallableTypeInterface> () const
   return this->is<CallableTypeInterface> ();
 }
 
+template <>
+WARN_UNUSED_RESULT inline bool
+BaseType::is<SubstitutionRef> () const
+{
+  auto kind = this->get_kind ();
+  return kind == FNPTR || kind == FNDEF || kind == CLOSURE || kind == ADT
+	 || kind == PROJECTION;
+}
+
+template <>
+WARN_UNUSED_RESULT inline bool
+BaseType::is<const SubstitutionRef> () const
+{
+  return this->is<SubstitutionRef> ();
+}
+
+template <>
+WARN_UNUSED_RESULT inline SubstitutionRef *
+BaseType::as<SubstitutionRef> ()
+{
+  auto kind = this->get_kind ();
+  switch (kind)
+    {
+    case FNDEF:
+      return static_cast<FnType *> (this);
+    case CLOSURE:
+      return static_cast<ClosureType *> (this);
+    case ADT:
+      return static_cast<ADTType *> (this);
+    case PROJECTION:
+      return static_cast<ProjectionType *> (this);
+    default:
+      rust_unreachable ();
+    }
+}
+
+template <>
+WARN_UNUSED_RESULT inline const SubstitutionRef *
+BaseType::as<const SubstitutionRef> () const
+{
+  auto kind = this->get_kind ();
+  switch (kind)
+    {
+    case FNDEF:
+      return static_cast<const FnType *> (this);
+    case CLOSURE:
+      return static_cast<const ClosureType *> (this);
+    case ADT:
+      return static_cast<const ADTType *> (this);
+    case PROJECTION:
+      return static_cast<const ProjectionType *> (this);
+    default:
+      rust_unreachable ();
+    }
+}
+
+template <>
+WARN_UNUSED_RESULT inline SubstitutionRef *
+BaseType::try_as<SubstitutionRef> ()
+{
+  if (this->is<SubstitutionRef> ())
+    {
+      return this->as<SubstitutionRef> ();
+    }
+  return nullptr;
+}
+
+template <>
+WARN_UNUSED_RESULT inline const SubstitutionRef *
+BaseType::try_as<const SubstitutionRef> () const
+{
+  if (this->is<const SubstitutionRef> ())
+    {
+      return this->as<const SubstitutionRef> ();
+    }
+  return nullptr;
+}
+
 } // namespace TyTy
 } // namespace Rust