[gcc r14-7946] gccrs: [E0769] Use of tuple struct/variant in struct variant

[Arthur Cohen]

https://gcc.gnu.org/g:af2ae3076418f7908cd4f7bb842718070429fdad

commit r14-7946-gaf2ae3076418f7908cd4f7bb842718070429fdad
Author: Muhammad Mahad <mahadtxt@gmail.com>
Date:   Wed Aug 16 15:30:45 2023 +0500

    gccrs: [E0769] Use of tuple struct/variant in struct variant
    
    gcc/rust/ChangeLog:
    
            * typecheck/rust-hir-type-check-pattern.cc (TypeCheckPattern::visit):
            Added error code and rich location.
    
    gcc/testsuite/ChangeLog:
    
            * rust/compile/match4.rs:
            Updated new error commment.
    
    Signed-off-by: Muhammad Mahad <mahadtxt@gmail.com>

Diff:
---
 gcc/rust/typecheck/rust-hir-type-check-pattern.cc | 10 ++++++++--
 gcc/testsuite/rust/compile/match4.rs              |  2 +-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/gcc/rust/typecheck/rust-hir-type-check-pattern.cc b/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
index 18e9b3442ac..8e9dd556a3c 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
@@ -184,8 +184,14 @@ TypeCheckPattern::visit (HIR::StructPattern &pattern)
     {
       std::string variant_type
 	= TyTy::VariantDef::variant_type_string (variant->get_variant_type ());
-      rust_error_at (pattern.get_locus (),
-		     "expected struct variant, found %s variant %s",
+
+      rich_location rich_locus (line_table, pattern.get_locus ());
+      std::string rich_msg = "use the tuple variant pattern syntax instead "
+			     + variant->get_identifier () + "(_)";
+      rich_locus.add_fixit_replace (rich_msg.c_str ());
+
+      rust_error_at (rich_locus, ErrorCode::E0769,
+		     "%s variant %qs written as struct variant",
 		     variant_type.c_str (),
 		     variant->get_identifier ().c_str ());
       return;
diff --git a/gcc/testsuite/rust/compile/match4.rs b/gcc/testsuite/rust/compile/match4.rs
index 35b90a64fa5..552aa163db5 100644
--- a/gcc/testsuite/rust/compile/match4.rs
+++ b/gcc/testsuite/rust/compile/match4.rs
@@ -10,7 +10,7 @@ fn inspect(f: Foo) {
         Foo::A => {}
         Foo::B => {}
         Foo::C { a } => {}
-        // { dg-error "expected struct variant, found tuple variant C" "" { target *-*-* } .-1 }
+        // { dg-error "tuple variant .C. written as struct variant" "" { target *-*-* } .-1 }
         Foo::D { x, y } => {}
     }
 }