From: Muhammad Mahad <mahadtxt@gmail.com>
Date: Tue, 15 Aug 2023 16:29:03 +0000 (+0500)
Subject: gccrs: [E0391] Detected type dependency cycle
X-Git-Tag: basepoints/gcc-15~2207
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b620e1d19f19325afe1d49ee8e2b8f6782a19761;p=thirdparty%2Fgcc.git

gccrs: [E0391] Detected type dependency cycle

This errorcode & message emits when cycle
detected when computing the super predicates
of `x` which requires computing the super
predicates of `y`, which again requires
computing the super predicates of `x`,
completing the cycle.

gcc/rust/ChangeLog:

	* typecheck/rust-hir-trait-resolve.cc (TraitResolver::resolve_trait):
	Updated errorcode & more userfriendly message.

gcc/testsuite/ChangeLog:

	* rust/compile/issue-1589.rs: Updated comment for dejagnu.
	* rust/compile/trait-cycle.rs: New relevant test.

Signed-off-by: Muhammad Mahad <mahadtxt@gmail.com>
---

diff --git a/gcc/rust/typecheck/rust-hir-trait-resolve.cc b/gcc/rust/typecheck/rust-hir-trait-resolve.cc
index b99fe2341af5..1d6a9fbdd37e 100644
--- a/gcc/rust/typecheck/rust-hir-trait-resolve.cc
+++ b/gcc/rust/typecheck/rust-hir-trait-resolve.cc
@@ -156,7 +156,10 @@ TraitResolver::resolve_trait (HIR::Trait *trait_reference)
   DefId trait_id = trait_reference->get_mappings ().get_defid ();
   if (context->trait_query_in_progress (trait_id))
     {
-      rust_error_at (trait_reference->get_locus (), "trait cycle detected");
+      rust_error_at (
+	trait_reference->get_locus (), ErrorCode::E0391,
+	"cycle detected when computing the super predicates of %qs",
+	trait_reference->get_name ().as_string ().c_str ());
       return &TraitReference::error_node ();
     }
 
diff --git a/gcc/testsuite/rust/compile/issue-1589.rs b/gcc/testsuite/rust/compile/issue-1589.rs
index 45f2415a8131..1dd7a45286c4 100644
--- a/gcc/testsuite/rust/compile/issue-1589.rs
+++ b/gcc/testsuite/rust/compile/issue-1589.rs
@@ -2,7 +2,7 @@
 pub trait Sized {}
 
 pub trait A: B {}
-// { dg-error "trait cycle detected" "" { target *-*-* } .-1 }
+// { dg-error "cycle detected when computing the super predicates of .A." "" { target *-*-* } .-1 }
 
 pub trait B: A {}
-// { dg-error "trait cycle detected" "" { target *-*-* } .-1 }
+// { dg-error "cycle detected when computing the super predicates of .B." "" { target *-*-* } .-1 }
diff --git a/gcc/testsuite/rust/compile/trait-cycle.rs b/gcc/testsuite/rust/compile/trait-cycle.rs
new file mode 100644
index 000000000000..3bcadbbdbd77
--- /dev/null
+++ b/gcc/testsuite/rust/compile/trait-cycle.rs
@@ -0,0 +1,4 @@
+pub trait FirstTrait: SecondTrait {}
+// { dg-error "cycle detected when computing the super predicates of .FirstTrait." "" { target *-*-* } .-1 }
+pub trait SecondTrait: FirstTrait {}
+// { dg-error "cycle detected when computing the super predicates of .SecondTrait." "" { target *-*-* } .-1 }