From: Abdul Rafey <abdulrafeyq@gmail.com>
Date: Sun, 29 Jan 2023 11:35:23 +0000 (+0530)
Subject: gccrs: fixed compiler error message on wildcard pattern within expression
X-Git-Tag: basepoints/gcc-14~162
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=760f529d8138b8b6afb6f17274af194d6fd5de12;p=thirdparty%2Fgcc.git

gccrs: fixed compiler error message on wildcard pattern within expression

gcc/rust/ChangeLog:

	* parse/rust-parse-impl.h (Parser::null_denotation): Add proper error
	when seeing wildcard var on right side of assignment.

gcc/testsuite/ChangeLog:

	* rust/compile/issue-867.rs: New test.

Signed-off-by: Abdul Rafey <abdulrafeyq@gmail.com>
---

diff --git a/gcc/rust/parse/rust-parse-impl.h b/gcc/rust/parse/rust-parse-impl.h
index d71bafded631..af749ca92001 100644
--- a/gcc/rust/parse/rust-parse-impl.h
+++ b/gcc/rust/parse/rust-parse-impl.h
@@ -13021,6 +13021,12 @@ Parser<ManagedTokenSource>::null_denotation (const_TokenPtr tok,
     case UNSAFE:
       return parse_unsafe_block_expr (std::move (outer_attrs),
 				      tok->get_locus ());
+    case UNDERSCORE:
+      add_error (
+	Error (tok->get_locus (),
+	       "use of %qs is not allowed on the right-side of an assignment",
+	       tok->get_token_description ()));
+      return nullptr;
     default:
       if (!restrictions.expr_can_be_null)
 	add_error (Error (tok->get_locus (),
diff --git a/gcc/testsuite/rust/compile/issue-867.rs b/gcc/testsuite/rust/compile/issue-867.rs
new file mode 100644
index 000000000000..8e120685c1a3
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-867.rs
@@ -0,0 +1,8 @@
+fn main() {
+    let _ = 42;
+    let a = _ + 123; // { dg-error "use of '_' is not allowed on the right-side of an assignment" }
+                     // { dg-error {failed to parse expression in let statement} "" { target *-*-* } .-1  }
+                     // { dg-error {failed to parse statement or expression without block in block expression} "" { target *-*-* } .-2 }
+                     // { dg-error {unrecognised token '\}' for start of item} "" { target *-*-* } .+2 }
+                     // { dg-error {failed to parse item in crate} "" { target *-*-* } .+1 }
+}