[gcc/devel/rust/master] Add missing unify rules for inference variables

[gcc/devel/rust/master] Add missing unify rules for inference variables

[Thomas Schwinge]

https://gcc.gnu.org/g:7609dfc63e021117c194544f83b2edce34a81520

commit 7609dfc63e021117c194544f83b2edce34a81520
Author: Philip Herron <philip.herron@embecosm.com>
Date:   Tue Apr 12 13:20:14 2022 +0100

    Add missing unify rules for inference variables
    
    Inference variables can unify with anything so this includes these
    covariant types like references/slices etc. This patch is needed for more
    complex type-checking in libcore and generics.

Diff:
---
 gcc/rust/typecheck/rust-tyty-rules.h | 60 ++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/gcc/rust/typecheck/rust-tyty-rules.h b/gcc/rust/typecheck/rust-tyty-rules.h
index 7c50112db60..f95e7bf7cd1 100644
--- a/gcc/rust/typecheck/rust-tyty-rules.h
+++ b/gcc/rust/typecheck/rust-tyty-rules.h
@@ -867,6 +867,18 @@ public:
 		       TyVar (base_resolved->get_ref ()));
   }
 
+  void visit (InferType &type) override
+  {
+    if (type.get_infer_kind () != InferType::InferTypeKind::GENERAL)
+      {
+	BaseRules::visit (type);
+	return;
+      }
+
+    resolved = base->clone ();
+    resolved->set_ref (type.get_ref ());
+  }
+
 private:
   BaseType *get_base () override { return base; }
 
@@ -896,6 +908,18 @@ public:
 			      TyVar (base_resolved->get_ref ()));
   }
 
+  void visit (InferType &type) override
+  {
+    if (type.get_infer_kind () != InferType::InferTypeKind::GENERAL)
+      {
+	BaseRules::visit (type);
+	return;
+      }
+
+    resolved = base->clone ();
+    resolved->set_ref (type.get_ref ());
+  }
+
 private:
   BaseType *get_base () override { return base; }
 
@@ -1140,6 +1164,18 @@ public:
 				    type.get_ident ().locus, fields);
   }
 
+  void visit (InferType &type) override
+  {
+    if (type.get_infer_kind () != InferType::InferTypeKind::GENERAL)
+      {
+	BaseRules::visit (type);
+	return;
+      }
+
+    resolved = base->clone ();
+    resolved->set_ref (type.get_ref ());
+  }
+
 private:
   BaseType *get_base () override { return base; }
 
@@ -1263,6 +1299,18 @@ public:
 				  base->mutability ());
   }
 
+  void visit (InferType &type) override
+  {
+    if (type.get_infer_kind () != InferType::InferTypeKind::GENERAL)
+      {
+	BaseRules::visit (type);
+	return;
+      }
+
+    resolved = base->clone ();
+    resolved->set_ref (type.get_ref ());
+  }
+
 private:
   BaseType *get_base () override { return base; }
 
@@ -1303,6 +1351,18 @@ public:
 				base->mutability ());
   }
 
+  void visit (InferType &type) override
+  {
+    if (type.get_infer_kind () != InferType::InferTypeKind::GENERAL)
+      {
+	BaseRules::visit (type);
+	return;
+      }
+
+    resolved = base->clone ();
+    resolved->set_ref (type.get_ref ());
+  }
+
 private:
   BaseType *get_base () override { return base; }