[gccrs COMMIT 2/2] gccrs: Fix missing unconstrained check to look at the full argument

[gerris.rs@gmail.com]

From: Philip Herron <herron.philip@googlemail.com>

Fixes Rust-GCC/gccrs#4822

gcc/rust/ChangeLog:

	* typecheck/rust-hir-type-check-base.cc (walk_type_to_constrain): prototype
	(walk_types_to_constrain): make sure to walk the argument too

gcc/testsuite/ChangeLog:

	* rust/compile/issue-4822.rs: New test.

Signed-off-by: Philip Herron <herron.philip@googlemail.com>
---
This change was merged into the gccrs repository and is posted here for
upstream visibility and potential drive-by review, as requested by GCC
release managers.
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Commit on github: https://github.com/Rust-GCC/gccrs/commit/40ce8273c361de572b4c60bbabc11c9a2c1eb97b

The commit has been mentioned in the following issue(s):
 - Rust-GCC/gccrs#4822: https://github.com/Rust-GCC/gccrs/issues/4822

The commit has been mentioned in the following pull-request(s):
 - https://github.com/Rust-GCC/gccrs/pull/4825

 gcc/rust/typecheck/rust-hir-type-check-base.cc |  5 ++++-
 gcc/testsuite/rust/compile/issue-4822.rs       | 11 +++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/rust/compile/issue-4822.rs

diff --git a/gcc/rust/typecheck/rust-hir-type-check-base.cc b/gcc/rust/typecheck/rust-hir-type-check-base.cc
index 97ff55400..b53232a57 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-base.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-base.cc
@@ -26,7 +26,6 @@
 #include "rust-type-util.h"
 #include "rust-attribute-values.h"
 #include "rust-tyty.h"
-#include "tree.h"
 
 namespace Rust {
 namespace Resolver {
@@ -58,6 +57,9 @@ TypeCheckBase::ResolvePredicateFromBound (
 				       is_qualified_type, is_super_trait);
 }
 
+static void walk_type_to_constrain (std::set<HirId> &constrained_symbols,
+				    TyTy::BaseType &r);
+
 static void
 walk_types_to_constrain (std::set<HirId> &constrained_symbols,
 			 const TyTy::SubstitutionArgumentMappings &constraints)
@@ -70,6 +72,7 @@ walk_types_to_constrain (std::set<HirId> &constrained_symbols,
 	  const auto p = arg->get_root ();
 	  constrained_symbols.insert (p->get_ref ());
 	  constrained_symbols.insert (p->get_ty_ref ());
+	  walk_type_to_constrain (constrained_symbols, *arg);
 
 	  if (p->has_substitutions_defined ())
 	    {
diff --git a/gcc/testsuite/rust/compile/issue-4822.rs b/gcc/testsuite/rust/compile/issue-4822.rs
new file mode 100644
index 000000000..45641ad3c
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-4822.rs
@@ -0,0 +1,11 @@
+#![feature(lang_items, no_core)]
+#![no_core]
+
+#[lang = "sized"]
+trait Sized {}
+
+trait PartialEq<Rhs> {}
+
+impl<A, B, const N: usize> PartialEq<[B; N]> for [A; N] {}
+
+fn main() {}
-- 
2.55.0