Rollup merge of #118759 - compiler-errors:bare-unit-structs, r=petrochenkov

Support bare unit structs in destructuring assignments

We should be allowed to use destructuring assignments on *bare* unit structs, not just unit structs that are located within other pattern constructors.

Fixes #118753

r? petrochenkov since you reviewed #95380, reassign if you're busy or don't want to review this.

compiler/rustc_ast_lowering/src/expr.rs

@@ -1222,6 +1222,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 | ExprKind::Struct(..)
                 | ExprKind::Tup(..)
                 | ExprKind::Underscore => false,
+                // Check for unit struct constructor.
+                ExprKind::Path(..) => lower_ctx.extract_unit_struct_path(lhs).is_none(),
                 // Check for tuple struct constructor.
                 ExprKind::Call(callee, ..) => lower_ctx.extract_tuple_struct_path(callee).is_none(),
                 ExprKind::Paren(e) => {