Unify the adjusted self argument to the self parameter on MethodCalls

When we must infer the substitutions on method calls we must make sure to
unify the self arguments from the receiver, taking into account the
autoderef mechanism. This enforces the type checks and fixes up any
inference variables along the way.

Addresses #808

3 files changed, 14 insertions, 4 deletions

diff --git a/gcc/rust/typecheck/rust-hir-type-check-expr.h b/gcc/rust/typecheck/rust-hir-type-check-expr.h
index 99696ae..d5d12b4 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-expr.h
+++ b/gcc/rust/typecheck/rust-hir-type-check-expr.h
@@ -295,6 +295,10 @@ public:
 	return;
       }
 
+    // Get the adjusted self
+    Adjuster adj (receiver_tyty);
+    TyTy::BaseType *adjusted_self = adj.adjust_type (adjustments);
+
     // store the adjustments for code-generation to know what to do
     context->insert_autoderef_mappings (expr.get_mappings ().get_hirid (),
 					std::move (adjustments));
@@ -401,7 +405,8 @@ public:
       }
 
     TyTy::BaseType *function_ret_tyty
-      = TyTy::TypeCheckMethodCallExpr::go (lookup, expr, context);
+      = TyTy::TypeCheckMethodCallExpr::go (lookup, expr, adjusted_self,
+					   context);
     if (function_ret_tyty == nullptr
 	|| function_ret_tyty->get_kind () == TyTy::TypeKind::ERROR)
       {
diff --git a/gcc/rust/typecheck/rust-tyty-call.h b/gcc/rust/typecheck/rust-tyty-call.h
index c11fd4d..3080427 100644
--- a/gcc/rust/typecheck/rust-tyty-call.h
+++ b/gcc/rust/typecheck/rust-tyty-call.h
@@ -88,9 +88,10 @@ class TypeCheckMethodCallExpr : private TyVisitor
 public:
   // Resolve the Method parameters and return back the return type
   static BaseType *go (BaseType *ref, HIR::MethodCallExpr &call,
+		       TyTy::BaseType *adjusted_self,
 		       Resolver::TypeCheckContext *context)
   {
-    TypeCheckMethodCallExpr checker (call, context);
+    TypeCheckMethodCallExpr checker (call, adjusted_self, context);
     ref->accept_vis (checker);
     return checker.resolved;
   }
@@ -125,13 +126,15 @@ public:
 
 private:
   TypeCheckMethodCallExpr (HIR::MethodCallExpr &c,
+			   TyTy::BaseType *adjusted_self,
 			   Resolver::TypeCheckContext *context)
-    : resolved (nullptr), call (c), context (context),
-      mappings (Analysis::Mappings::get ())
+    : resolved (nullptr), call (c), adjusted_self (adjusted_self),
+      context (context), mappings (Analysis::Mappings::get ())
   {}
 
   BaseType *resolved;
   HIR::MethodCallExpr &call;
+  TyTy::BaseType *adjusted_self;
   Resolver::TypeCheckContext *context;
   Analysis::Mappings *mappings;
 };
diff --git a/gcc/rust/typecheck/rust-tyty.cc b/gcc/rust/typecheck/rust-tyty.cc
index 378416f..add4dbe 100644
--- a/gcc/rust/typecheck/rust-tyty.cc
+++ b/gcc/rust/typecheck/rust-tyty.cc
@@ -2786,6 +2786,8 @@ TypeCheckCallExpr::visit (FnPtr &type)
 void
 TypeCheckMethodCallExpr::visit (FnType &type)
 {
+  adjusted_self->unify (type.get_self_type ());
+
   // +1 for the receiver self
   size_t num_args_to_call = call.num_params () + 1;
   if (num_args_to_call != type.num_params ())