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.philip@googlemail.com>

diff --git a/gcc/rust/typecheck/rust-hir-type-check-pattern.cc b/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
index 19f742f21540304d9c5e9e1e2fbc5b5d28046464..c7f29e28b2de7fce6b1104911805d904b144add2 100644 (file)
--- 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 (file)
index 0000000..3ad7085
--- /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)>);
+}