src/test/ui/pattern/usefulness/match-empty.rs

   1 #![feature(never_type)]
   2 #![deny(unreachable_patterns)]
   3 enum Foo {}
   4
   5 struct NonEmptyStruct(bool); //~ `NonEmptyStruct` defined here
   6 union NonEmptyUnion1 { //~ `NonEmptyUnion1` defined here
   7     foo: (),
   8 }
   9 union NonEmptyUnion2 { //~ `NonEmptyUnion2` defined here
  10     foo: (),
  11     bar: (),
  12 }
  13 enum NonEmptyEnum1 { //~ `NonEmptyEnum1` defined here
  14     Foo(bool),
  15     //~^ not covered
  16     //~| not covered
  17 }
  18 enum NonEmptyEnum2 { //~ `NonEmptyEnum2` defined here
  19     Foo(bool),
  20     //~^ not covered
  21     //~| not covered
  22     Bar,
  23     //~^ not covered
  24     //~| not covered
  25 }
  26 enum NonEmptyEnum5 { //~ `NonEmptyEnum5` defined here
  27     V1, V2, V3, V4, V5,
  28 }
  29
  30 macro_rules! match_empty {
  31     ($e:expr) => {
  32         match $e {}
  33     };
  34 }
  35 macro_rules! match_false {
  36     ($e:expr) => {
  37         match $e {
  38             _ if false => {}
  39         }
  40     };
  41 }
  42
  43 fn foo(x: Foo) {
  44     match_empty!(x); // ok
  45     match_false!(x); // Not detected as unreachable nor exhaustive.
  46     //~^ ERROR non-exhaustive patterns: `_` not covered
  47     match x {
  48         _ => {}, // Not detected as unreachable, see #55123.
  49     }
  50 }
  51
  52 fn main() {
  53     // `exhaustive_patterns` is not on, so uninhabited branches are not detected as unreachable.
  54     match None::<!> {
  55         None => {}
  56         Some(_) => {}
  57     }
  58     match None::<Foo> {
  59         None => {}
  60         Some(_) => {}
  61     }
  62
  63     match_empty!(0u8);
  64     //~^ ERROR type `u8` is non-empty
  65     match_empty!(NonEmptyStruct(true));
  66     //~^ ERROR type `NonEmptyStruct` is non-empty
  67     match_empty!((NonEmptyUnion1 { foo: () }));
  68     //~^ ERROR type `NonEmptyUnion1` is non-empty
  69     match_empty!((NonEmptyUnion2 { foo: () }));
  70     //~^ ERROR type `NonEmptyUnion2` is non-empty
  71     match_empty!(NonEmptyEnum1::Foo(true));
  72     //~^ ERROR `Foo(_)` not covered
  73     match_empty!(NonEmptyEnum2::Foo(true));
  74     //~^ ERROR `Foo(_)` and `Bar` not covered
  75     match_empty!(NonEmptyEnum5::V1);
  76     //~^ ERROR `V1`, `V2`, `V3` and 2 more not covered
  77
  78     match_false!(0u8);
  79     //~^ ERROR `_` not covered
  80     match_false!(NonEmptyStruct(true));
  81     //~^ ERROR `NonEmptyStruct(_)` not covered
  82     match_false!((NonEmptyUnion1 { foo: () }));
  83     //~^ ERROR `NonEmptyUnion1 { .. }` not covered
  84     match_false!((NonEmptyUnion2 { foo: () }));
  85     //~^ ERROR `NonEmptyUnion2 { .. }` not covered
  86     match_false!(NonEmptyEnum1::Foo(true));
  87     //~^ ERROR `Foo(_)` not covered
  88     match_false!(NonEmptyEnum2::Foo(true));
  89     //~^ ERROR `Foo(_)` and `Bar` not covered
  90     match_false!(NonEmptyEnum5::V1);
  91     //~^ ERROR `V1`, `V2`, `V3` and 2 more not covered
  92 }