[gcc/devel/rust/master] gccrs: fix bug in pattern check for tuples

[Thomas Schwinge via Gcc-cvs]

https://gcc.gnu.org/g:38af9fef52e716ca38cf182a9d86ff49953a586f

commit 38af9fef52e716ca38cf182a9d86ff49953a586f
Author: Philip Herron <herron.phi...@googlemail.com>
Date:   Sun Feb 4 17:07:05 2024 +0000

    gccrs: fix bug in pattern check for tuples
    
    We can point to generic parent types which means we need to do the shallow
    resolve thing that rustc does. We have destructure which is similar to get
    what the parameter type points to.
    
    Fixes #2775
    
    gcc/rust/ChangeLog:
    
            * typecheck/rust-hir-type-check-pattern.cc 
(TypeCheckPattern::visit): use destructure
    
    gcc/testsuite/ChangeLog:
    
            * rust/compile/issue-2775.rs: New test.
    
    Signed-off-by: Philip Herron <herron.phi...@googlemail.com>

Diff:
---
 gcc/rust/typecheck/rust-hir-type-check-pattern.cc |  6 ++++--
 gcc/testsuite/rust/compile/issue-2775.rs          | 11 +++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/gcc/rust/typecheck/rust-hir-type-check-pattern.cc 
b/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
index 7ad0147327cb..9d74def0b5c6 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
@@ -302,7 +302,8 @@ TypeCheckPattern::visit (HIR::TuplePattern &pattern)
          = *static_cast<HIR::TuplePatternItemsMultiple *> (
            pattern.get_items ().get ());
 
-       if (parent->get_kind () != TyTy::TUPLE)
+       auto resolved_parent = parent->destructure ();
+       if (resolved_parent->get_kind () != TyTy::TUPLE)
          {
            rust_error_at (pattern.get_locus (), "expected %s, found tuple",
                           parent->as_string ().c_str ());
@@ -312,7 +313,8 @@ TypeCheckPattern::visit (HIR::TuplePattern &pattern)
        const auto &patterns = ref.get_patterns ();
        size_t nitems_to_resolve = patterns.size ();
 
-       TyTy::TupleType &par = *static_cast<TyTy::TupleType *> (parent);
+       TyTy::TupleType &par
+         = *static_cast<TyTy::TupleType *> (resolved_parent);
        if (patterns.size () != par.get_fields ().size ())
          {
            emit_pattern_size_error (pattern, par.get_fields ().size (),
diff --git a/gcc/testsuite/rust/compile/issue-2775.rs 
b/gcc/testsuite/rust/compile/issue-2775.rs
new file mode 100644
index 000000000000..3ad7085785ea
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-2775.rs
@@ -0,0 +1,11 @@
+// { dg-options "-w" }
+#[lang = "sized"]
+pub trait Sized {}
+
+struct Ref<'a, T> {
+    x: &'a T,
+}
+
+pub fn test<'a, 'b, 'c>() {
+    let (_, &&Ref::<(&'_ i32, i32)> { x: &(a, b) }): (i32, &'_ &'b Ref<'b, 
(&'c i32, i32)>);
+}