[gcc/devel/rust/master] resolve: Fix multiple bindings handling in match

[Thomas Schwinge]

https://gcc.gnu.org/g:dd4038083ef08ce8e8456261389d4b26f5dd7ace

commit dd4038083ef08ce8e8456261389d4b26f5dd7ace
Author: Mahmoud Mohamed <mahadelr19@gmail.com>
Date:   Thu Mar 16 14:53:44 2023 +0300

    resolve: Fix multiple bindings handling in match
    
    gcc/rust/ChangeLog:
    
            * resolve/rust-ast-resolve-expr.cc (ResolveExpr::visit):
            Push a Product context instead of an Or context.
    
    gcc/testsuite/ChangeLog:
    
            * rust/compile/multiple_bindings2.rs: New test.
    
    Signed-off-by: Mahmoud Mohamed <mahadelr19@gmail.com>

Diff:
---
 gcc/rust/resolve/rust-ast-resolve-expr.cc        | 12 ++++++------
 gcc/testsuite/rust/compile/multiple_bindings2.rs | 14 ++++++++++++++
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/gcc/rust/resolve/rust-ast-resolve-expr.cc b/gcc/rust/resolve/rust-ast-resolve-expr.cc
index ff9f7ef0cd1..a6b16f32a29 100644
--- a/gcc/rust/resolve/rust-ast-resolve-expr.cc
+++ b/gcc/rust/resolve/rust-ast-resolve-expr.cc
@@ -207,10 +207,10 @@ ResolveExpr::visit (AST::IfLetExpr &expr)
   resolver->push_new_type_rib (resolver->get_type_scope ().peek ());
   resolver->push_new_label_rib (resolver->get_type_scope ().peek ());
 
-  // FIXME: this declaration should be removed after refactoring
-  // parse_match_arm_patterns output into an AltPattern
+  // We know expr.get_patterns () has one pattern at most
+  // so there's no reason to handle it like an AltPattern.
   std::vector<PatternBinding> bindings
-    = {PatternBinding (PatternBoundCtx::Or, std::set<Identifier> ())};
+    = {PatternBinding (PatternBoundCtx::Product, std::set<Identifier> ())};
 
   for (auto &pattern : expr.get_patterns ())
     {
@@ -522,10 +522,10 @@ ResolveExpr::visit (AST::MatchExpr &expr)
 	ResolveExpr::go (arm.get_guard_expr ().get (), prefix,
 			 canonical_prefix);
 
-      // FIXME: this declaration should be removed after refactoring
-      // parse_match_arms_patterns output into a single AltPattern
+      // We know expr.get_patterns () has one pattern at most
+      // so there's no reason to handle it like an AltPattern.
       std::vector<PatternBinding> bindings
-	= {PatternBinding (PatternBoundCtx::Or, std::set<Identifier> ())};
+	= {PatternBinding (PatternBoundCtx::Product, std::set<Identifier> ())};
 
       // insert any possible new patterns
       for (auto &pattern : arm.get_patterns ())
diff --git a/gcc/testsuite/rust/compile/multiple_bindings2.rs b/gcc/testsuite/rust/compile/multiple_bindings2.rs
new file mode 100644
index 00000000000..e62b18f6843
--- /dev/null
+++ b/gcc/testsuite/rust/compile/multiple_bindings2.rs
@@ -0,0 +1,14 @@
+fn main()
+{
+  match (1, 2) {
+    (a, a) => {},
+  }
+  // { dg-error "identifier .a. is bound more than once in the same pattern .E0416." "" { target *-*-* } .-2 }
+
+  if let (a, a) = (1, 2) {}
+  // { dg-error "identifier .a. is bound more than once in the same pattern .E0416." "" { target *-*-* } .-1 }
+
+  let (a, a) = (1, 2);
+  // { dg-error "identifier .a. is bound more than once in the same pattern .E0416." "" { target *-*-* } .-1 }
+
+}