gccrs: Add check for super traits being implemented by Self

We need to recursively check the super traits of the predicate the Self
type is trying to implement. Otherwise its cannot implement it.

Fixes #3553

gcc/rust/ChangeLog:

	* typecheck/rust-hir-type-check-item.cc (TypeCheckItem::resolve_impl_block_substitutions):
	Track the polarity
	* typecheck/rust-tyty-bounds.cc (TypeBoundPredicate::validate_type_implements_this):
	new validator
	* typecheck/rust-tyty.h: new prototypes

gcc/testsuite/ChangeLog:

	* rust/compile/issue-3553.rs: New test.

Signed-off-by: Philip Herron <[email protected]>

Author: philberty

gcc/rust/typecheck/rust-hir-type-check-item.cc

@@ -725,11 +725,11 @@ TypeCheckItem::resolve_impl_block_substitutions (HIR::ImplBlock &impl_block,
 
       // we don't error out here see: gcc/testsuite/rust/compile/traits2.rs
       // for example
-      specified_bound = get_predicate_from_bound (ref, impl_block.get_type ());
+      specified_bound = get_predicate_from_bound (ref, impl_block.get_type (),
+						  impl_block.get_polarity ());
     }
 
   TyTy::BaseType *self = TypeCheckType::Resolve (impl_block.get_type ());
-
   if (self->is<TyTy::ErrorType> ())
     {
       // we cannot check for unconstrained type arguments when the Self type is
@@ -771,7 +771,14 @@ TypeCheckItem::validate_trait_impl_block (
 
       // we don't error out here see: gcc/testsuite/rust/compile/traits2.rs
       // for example
-      specified_bound = get_predicate_from_bound (ref, impl_block.get_type ());
+      specified_bound = get_predicate_from_bound (ref, impl_block.get_type (),
+						  impl_block.get_polarity ());
+
+      // need to check that if this specified bound has super traits does this
+      // Self
+      // implement them?
+      specified_bound.validate_type_implements_super_traits (
+	*self, impl_block.get_type (), impl_block.get_trait_ref ());
     }
 
   bool is_trait_impl_block = !trait_reference->is_error ();

gcc/rust/typecheck/rust-tyty-bounds.cc

@@ -828,6 +828,65 @@ TypeBoundPredicate::is_equal (const TypeBoundPredicate &other) const
   return true;
 }
 
+bool
+TypeBoundPredicate::validate_type_implements_super_traits (
+  TyTy::BaseType &self, HIR::Type &impl_type, HIR::Type &trait) const
+{
+  if (get_polarity () != BoundPolarity::RegularBound)
+    return true;
+
+  auto &ptref = *get ();
+  for (auto &super : super_traits)
+    {
+      if (super.get_polarity () != BoundPolarity::RegularBound)
+	continue;
+
+      if (!super.validate_type_implements_this (self, impl_type, trait))
+	{
+	  auto &sptref = *super.get ();
+
+	  // emit error
+	  std::string fixit1
+	    = "required by this bound in: " + ptref.get_name ();
+	  std::string fixit2 = "the trait " + sptref.get_name ()
+			       + " is not implemented for "
+			       + impl_type.as_string ();
+
+	  rich_location r (line_table, trait.get_locus ());
+	  r.add_fixit_insert_after (super.get_locus (), fixit1.c_str ());
+	  r.add_fixit_insert_after (trait.get_locus (), fixit2.c_str ());
+	  rust_error_at (r, ErrorCode::E0277,
+			 "the trait bound %<%s: %s%> is not satisfied",
+			 impl_type.as_string ().c_str (),
+			 sptref.get_name ().c_str ());
+
+	  return false;
+	}
+
+      if (!super.validate_type_implements_super_traits (self, impl_type, trait))
+	return false;
+    }
+
+  return true;
+}
+
+bool
+TypeBoundPredicate::validate_type_implements_this (TyTy::BaseType &self,
+						   HIR::Type &impl_type,
+						   HIR::Type &trait) const
+{
+  const auto &ptref = *get ();
+  auto probed_bounds = Resolver::TypeBoundsProbe::Probe (&self);
+  for (auto &elem : probed_bounds)
+    {
+      auto &tref = *(elem.first);
+      if (ptref.is_equal (tref))
+	return true;
+    }
+
+  return false;
+}
+
 // trait item reference
 
 const Resolver::TraitItemReference *

gcc/rust/typecheck/rust-tyty.h

@@ -578,6 +578,14 @@ class TypeBoundPredicate : public SubstitutionRef
 
   bool is_equal (const TypeBoundPredicate &other) const;
 
+  bool validate_type_implements_super_traits (TyTy::BaseType &self,
+					      HIR::Type &impl_type,
+					      HIR::Type &trait) const;
+
+  bool validate_type_implements_this (TyTy::BaseType &self,
+				      HIR::Type &impl_type,
+				      HIR::Type &trait) const;
+
 private:
   struct mark_is_error
   {

gcc/testsuite/rust/compile/issue-3553.rs

@@ -0,0 +1,18 @@
+trait Foo {
+    fn f(&self) -> isize;
+}
+
+trait Bar: Foo {
+    fn g(&self) -> isize;
+}
+
+struct A {
+    x: isize,
+}
+
+impl Bar for A {
+    // { dg-error "the trait bound .A: Foo. is not satisfied .E0277." "" { target *-*-* } .-1 }
+    fn g(&self) -> isize {
+        self.f()
+    }
+}