[gcc r14-7540] gccrs: Fix infinite loop with parsing invalid generic parameters

[Arthur Cohen]

https://gcc.gnu.org/g:582accedb77b7b957e1322966a0875491156d13a

commit r14-7540-g582accedb77b7b957e1322966a0875491156d13a
Author: Owen Avery <powerboat9.gamer@gmail.com>
Date:   Tue Apr 18 00:46:59 2023 -0400

    gccrs: Fix infinite loop with parsing invalid generic parameters
    
    gcc/rust/ChangeLog:
    
            * parse/rust-parse-impl.h
            (Parser::parse_generic_params):
            Handle parameter parsing error.
    
    gcc/testsuite/ChangeLog:
    
            * rust/compile/issue-2125.rs: New test.
    
    Signed-off-by: Owen Avery <powerboat9.gamer@gmail.com>

Diff:
---
 gcc/rust/parse/rust-parse-impl.h         | 2 ++
 gcc/testsuite/rust/compile/issue-2125.rs | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/gcc/rust/parse/rust-parse-impl.h b/gcc/rust/parse/rust-parse-impl.h
index 0fb96dcfb51..042018de9a2 100644
--- a/gcc/rust/parse/rust-parse-impl.h
+++ b/gcc/rust/parse/rust-parse-impl.h
@@ -3127,6 +3127,8 @@ Parser<ManagedTokenSource>::parse_generic_params (EndTokenPred is_end_token)
 	  generic_params.emplace_back (std::move (param));
 	  maybe_skip_token (COMMA);
 	}
+      else
+	break;
     }
 
   // FIXME: Add reordering hint
diff --git a/gcc/testsuite/rust/compile/issue-2125.rs b/gcc/testsuite/rust/compile/issue-2125.rs
new file mode 100644
index 00000000000..cbcf4cb133f
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-2125.rs
@@ -0,0 +1,2 @@
+// { dg-timeout 5 }
+struct S<$>; // { dg-error ".*" }