Refactor Method resolution to take advantage of PathProbe

This canonicalizes method resolution to the Path Probe used for Path expr
resolution. So any errors will gain the same diagnostics.

2 files changed, 39 insertions, 77 deletions

diff --git a/gcc/rust/typecheck/rust-hir-method-resolve.h b/gcc/rust/typecheck/rust-hir-method-resolve.h
index 35a5502..b2391e3 100644
--- a/gcc/rust/typecheck/rust-hir-method-resolve.h
+++ b/gcc/rust/typecheck/rust-hir-method-resolve.h
@@ -22,6 +22,7 @@
 #include "rust-hir-type-check-base.h"
 #include "rust-hir-full.h"
 #include "rust-tyty.h"
+#include "rust-hir-path-probe.h"
 #include "rust-substitution-mapper.h"
 
 namespace Rust {
@@ -32,74 +33,32 @@ class MethodResolution : public TypeCheckBase
   using Rust::Resolver::TypeCheckBase::visit;
 
 public:
-  static std::vector<HIR::Method *> Probe (TyTy::BaseType *receiver,
-					   HIR::PathExprSegment method_name)
+  static std::vector<PathProbeCandidate>
+  Probe (std::vector<PathProbeCandidate> &path_candidates)
   {
-    MethodResolution probe (receiver, method_name);
-
-    // lookup impl items for this crate and find all methods that can resolve to
-    // this receiver
-    probe.mappings->iterate_impl_items (
-      [&] (HirId id, HIR::InherentImplItem *item,
-	   HIR::InherentImpl *impl) mutable -> bool {
-	item->accept_vis (probe);
-	return true;
-      });
-
-    return probe.probed;
+    MethodResolution probe;
+    for (auto &c : path_candidates)
+      probe.process_candidate (c);
+
+    return probe.candidates;
   }
 
-  void visit (HIR::Method &method) override
+  void process_candidate (PathProbeCandidate &candidate)
   {
-    TyTy::BaseType *self_lookup = nullptr;
-    if (!context->lookup_type (
-	  method.get_self_param ().get_mappings ().get_hirid (), &self_lookup))
-      {
-	rust_error_at (method.get_self_param ().get_locus (),
-		       "failed to lookup lookup self type in MethodProbe");
-	return;
-      }
-
-    // are the names the same
-    HIR::PathIdentSegment seg = method_name.get_segment ();
-    if (seg.as_string ().compare (method.get_method_name ()) != 0)
-      {
-	// if the method name does not match then this is not a valid match
-	return;
-      }
-
-    if (self_lookup->get_kind () != receiver->get_kind ())
-      return;
-
-    if (receiver->has_subsititions_defined ()
-	!= self_lookup->has_subsititions_defined ())
-      return;
-
-    if (self_lookup->has_subsititions_defined ())
-      {
-	// we assume the receiver should be fully substituted at this stage
-	self_lookup = SubstMapperFromExisting::Resolve (receiver, self_lookup);
-      }
-
-    if (!receiver->is_equal (*self_lookup))
-      {
-	// incompatible self argument then this is not a valid method for this
-	// receiver
-	return;
-      }
-
-    probed.push_back (&method);
+    is_method_flag = false;
+    candidate.impl_item->accept_vis (*this);
+
+    if (is_method_flag)
+      candidates.push_back (candidate);
   }
 
-private:
-  MethodResolution (TyTy::BaseType *receiver, HIR::PathExprSegment method_name)
-    : TypeCheckBase (), receiver (receiver), method_name (method_name)
-  {}
+  void visit (HIR::Method &method) override { is_method_flag = true; }
 
-  TyTy::BaseType *receiver;
-  HIR::PathExprSegment method_name;
+private:
+  MethodResolution () : TypeCheckBase () {}
 
-  std::vector<HIR::Method *> probed;
+  bool is_method_flag;
+  std::vector<PathProbeCandidate> candidates;
 };
 
 } // namespace Resolver
diff --git a/gcc/rust/typecheck/rust-hir-type-check-expr.h b/gcc/rust/typecheck/rust-hir-type-check-expr.h
index b946812..cb2f250 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-expr.h
+++ b/gcc/rust/typecheck/rust-hir-type-check-expr.h
@@ -210,34 +210,37 @@ public:
     // which is simple. There will need to be adjustments to ensure we can turn
     // the receiver into borrowed references etc
 
-    auto probes
-      = MethodResolution::Probe (receiver_tyty, expr.get_method_name ());
-    if (probes.size () == 0)
+    auto candidates
+      = PathProbeType::Probe (receiver_tyty,
+			      expr.get_method_name ().get_segment ());
+    if (candidates.size () == 0)
       {
 	rust_error_at (expr.get_locus (),
 		       "failed to resolve the PathExprSegment to any Method");
 	return;
       }
-    else if (probes.size () > 1)
+
+    // filter all methods
+    auto possible_methods = MethodResolution::Probe (candidates);
+    if (possible_methods.size () == 0)
       {
-	rust_error_at (
-	  expr.get_locus (),
-	  "multiple candidates in MethodCallExpr have been probed is "
-	  "not currently supported");
+	rust_error_at (expr.get_method_name ().get_locus (),
+		       "no method named %s found in scope",
+		       expr.get_method_name ().as_string ().c_str ());
 	return;
       }
-
-    auto resolved_method = probes.at (0);
-    TyTy::BaseType *lookup_tyty;
-    if (!context->lookup_type (resolved_method->get_mappings ().get_hirid (),
-			       &lookup_tyty))
+    else if (possible_methods.size () > 1)
       {
-	rust_error_at (resolved_method->get_locus (),
-		       "failed to lookup type for CallExpr: %s",
-		       expr.as_string ().c_str ());
+	ReportMultipleCandidateError::Report (
+	  possible_methods, expr.get_method_name ().get_segment (),
+	  expr.get_method_name ().get_locus ());
 	return;
       }
 
+    auto resolved_candidate = possible_methods.at (0);
+    HIR::InherentImplItem *resolved_method = resolved_candidate.impl_item;
+    TyTy::BaseType *lookup_tyty = resolved_candidate.ty;
+
     TyTy::BaseType *lookup = lookup_tyty;
     if (lookup_tyty->get_kind () == TyTy::TypeKind::FNDEF)
       {
@@ -270,7 +273,7 @@ public:
     // set up the resolved name on the path
     resolver->insert_resolved_name (
       expr.get_mappings ().get_nodeid (),
-      resolved_method->get_mappings ().get_nodeid ());
+      resolved_method->get_impl_mappings ().get_nodeid ());
 
     // return the result of the function back
     infered = function_ret_tyty;