}
}
}
+ hir::ExprAssign(ref lhs, ref rhs) => {
+ if let hir::ExprField(ref base_expr, field) = lhs.node {
+ if let ty::TyAdt(adt, ..) = self.tables.expr_ty_adjusted(base_expr).sty {
+ if adt.is_union() {
+ let field_ty = self.tables.expr_ty_adjusted(lhs);
+ let param_env = self.tcx.parameter_environment(adt.did);
+ if field_ty.moves_by_default(self.tcx, ¶m_env, field.span) {
+ self.require_unsafe(field.span,
+ "assignment to non-`Copy` union field");
+ }
+ // Do not walk the field expr again.
+ intravisit::walk_expr(self, base_expr);
+ intravisit::walk_expr(self, rhs);
+ return
+ }
+ }
+ }
+ }
_ => {}
}
#![feature(untagged_unions)]
-union U {
+union U1 {
a: u8
}
+union U2 {
+ a: String
+}
+
+union U3<T> {
+ a: T
+}
+
+union U4<T: Copy> {
+ a: T
+}
+
+fn generic_noncopy<T: Default>() {
+ let mut u3 = U3 { a: T::default() };
+ u3.a = T::default(); //~ ERROR assignment to non-`Copy` union field requires unsafe
+}
+
+fn generic_copy<T: Copy + Default>() {
+ let mut u3 = U3 { a: T::default() };
+ // FIXME: it should be known here that `T: Copy`, need to use correct "parameter environment"
+ u3.a = T::default(); //~ ERROR assignment to non-`Copy` union field requires unsafe
+ let mut u4 = U4 { a: T::default() };
+ u4.a = T::default(); // OK
+}
+
fn main() {
- let mut u = U { a: 10 }; // OK
- let a = u.a; //~ ERROR access to union field requires unsafe function or block
- u.a = 11; //~ ERROR access to union field requires unsafe function or block
- let U { a } = u; //~ ERROR matching on union field requires unsafe function or block
- if let U { a: 12 } = u {} //~ ERROR matching on union field requires unsafe function or block
- // let U { .. } = u; // OK
+ let mut u1 = U1 { a: 10 }; // OK
+ let a = u1.a; //~ ERROR access to union field requires unsafe
+ u1.a = 11; // OK
+ let U1 { a } = u1; //~ ERROR matching on union field requires unsafe
+ if let U1 { a: 12 } = u1 {} //~ ERROR matching on union field requires unsafe
+ // let U1 { .. } = u1; // OK
+
+ let mut u2 = U2 { a: String::from("old") }; // OK
+ u2.a = String::from("new"); //~ ERROR assignment to non-`Copy` union field requires unsafe
+ let mut u3 = U3 { a: 0 }; // OK
+ u3.a = 1; // OK
+ let mut u3 = U3 { a: String::from("old") }; // OK
+ u3.a = String::from("new"); //~ ERROR assignment to non-`Copy` union field requires unsafe
}