Merge #1519

1519: Fix generic substitution on unit structs r=philberty a=philberty

Fixes #1518

Co-authored-by: Philip Herron <philip.herron@embecosm.com>

4 files changed, 37 insertions, 0 deletions

diff --git a/gcc/rust/typecheck/rust-hir-trait-resolve.cc b/gcc/rust/typecheck/rust-hir-trait-resolve.cc
index 7357585..146fe26 100644
--- a/gcc/rust/typecheck/rust-hir-trait-resolve.cc
+++ b/gcc/rust/typecheck/rust-hir-trait-resolve.cc
@@ -368,6 +368,9 @@ void
 AssociatedImplTrait::setup_associated_types (
   const TyTy::BaseType *self, const TyTy::TypeBoundPredicate &bound)
 {
+  if (!bound.contains_associated_types ())
+    return;
+
   // compute the constrained impl block generic arguments based on self and the
   // higher ranked trait bound
   TyTy::BaseType *receiver = self->clone ();
diff --git a/gcc/rust/typecheck/rust-hir-type-check-expr.cc b/gcc/rust/typecheck/rust-hir-type-check-expr.cc
index 57ed370..9a0d144 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-expr.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-expr.cc
@@ -1024,6 +1024,11 @@ TypeCheckExpr::visit (HIR::MethodCallExpr &expr)
       return;
     }
 
+  rust_debug_loc (expr.get_method_name ().get_locus (),
+		  "resolved method to: {%u} {%s}",
+		  candidate.candidate.ty->get_ref (),
+		  candidate.candidate.ty->debug_str ().c_str ());
+
   // Get the adjusted self
   Adjuster adj (receiver_tyty);
   TyTy::BaseType *adjusted_self = adj.adjust_type (candidate.adjustments);
@@ -1120,6 +1125,9 @@ TypeCheckExpr::visit (HIR::MethodCallExpr &expr)
   // apply any remaining generic arguments
   if (expr.get_method_name ().has_generic_args ())
     {
+      rust_debug_loc (expr.get_method_name ().get_generic_args ().get_locus (),
+		      "applying generic arguments to method_call: {%s}",
+		      lookup->debug_str ().c_str ());
       HIR::GenericArgs &args = expr.get_method_name ().get_generic_args ();
       lookup
 	= SubstMapper::Resolve (lookup, expr.get_method_name ().get_locus (),
@@ -1129,10 +1137,14 @@ TypeCheckExpr::visit (HIR::MethodCallExpr &expr)
     }
   else if (lookup->needs_generic_substitutions ())
     {
+      rust_debug ("method needs inference: {%s}",
+		  lookup->debug_str ().c_str ());
       lookup = SubstMapper::InferSubst (lookup,
 					expr.get_method_name ().get_locus ());
     }
 
+  rust_debug ("type-checking method_call: {%s}", lookup->debug_str ().c_str ());
+
   TyTy::BaseType *function_ret_tyty
     = TyTy::TypeCheckMethodCallExpr::go (lookup, expr, adjusted_self, context);
   if (function_ret_tyty == nullptr
diff --git a/gcc/rust/typecheck/rust-tyty-bounds.cc b/gcc/rust/typecheck/rust-tyty-bounds.cc
index 7a1562a..811d64b 100644
--- a/gcc/rust/typecheck/rust-tyty-bounds.cc
+++ b/gcc/rust/typecheck/rust-tyty-bounds.cc
@@ -374,6 +374,21 @@ TypeBoundPredicate::requires_generic_args () const
   return substitutions.size () > 1;
 }
 
+bool
+TypeBoundPredicate::contains_associated_types () const
+{
+  auto trait_ref = get ();
+  for (const auto &trait_item : trait_ref->get_trait_items ())
+    {
+      bool is_associated_type
+	= trait_item.get_trait_item_type ()
+	  == Resolver::TraitItemReference::TraitItemType::TYPE;
+      if (is_associated_type)
+	return true;
+    }
+  return false;
+}
+
 // trait item reference
 
 const Resolver::TraitItemReference *
diff --git a/gcc/rust/typecheck/rust-tyty.h b/gcc/rust/typecheck/rust-tyty.h
index a351932..74c8c35 100644
--- a/gcc/rust/typecheck/rust-tyty.h
+++ b/gcc/rust/typecheck/rust-tyty.h
@@ -1057,6 +1057,8 @@ public:
 
   bool requires_generic_args () const;
 
+  bool contains_associated_types () const;
+
 private:
   DefId reference;
   Location locus;
@@ -1360,6 +1362,11 @@ public:
 
   bool is_concrete () const override final
   {
+    if (is_unit ())
+      {
+	return !needs_substitution ();
+      }
+
     for (auto &variant : variants)
       {
 	for (auto &field : variant->get_fields ())