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

   1 // aux-build:empty.rs
   2 #![feature(never_type)]
   3 #![feature(never_type_fallback)]
   4 #![deny(unreachable_patterns)]
   5
   6 extern crate empty;
   7
   8 enum EmptyEnum {}
   9
  10 struct NonEmptyStruct(bool); //~ `NonEmptyStruct` defined here
  11 union NonEmptyUnion1 { //~ `NonEmptyUnion1` defined here
  12     foo: (),
  13 }
  14 union NonEmptyUnion2 { //~ `NonEmptyUnion2` defined here
  15     foo: (),
  16     bar: (),
  17 }
  18 enum NonEmptyEnum1 { //~ `NonEmptyEnum1` defined here
  19     Foo(bool),
  20     //~^ not covered
  21     //~| not covered
  22 }
  23 enum NonEmptyEnum2 { //~ `NonEmptyEnum2` defined here
  24     Foo(bool),
  25     //~^ not covered
  26     //~| not covered
  27     Bar,
  28     //~^ not covered
  29     //~| not covered
  30 }
  31 enum NonEmptyEnum5 { //~ `NonEmptyEnum5` defined here
  32     V1, V2, V3, V4, V5,
  33 }
  34
  35 macro_rules! match_empty {
  36     ($e:expr) => {
  37         match $e {}
  38     };
  39 }
  40 macro_rules! match_false {
  41     ($e:expr) => {
  42         match $e {
  43             _ if false => {}
  44         }
  45     };
  46 }
  47
  48 fn empty_enum(x: EmptyEnum) {
  49     match x {} // ok
  50     match x {
  51         _ => {}, //~ ERROR unreachable pattern
  52     }
  53     match x {
  54         _ if false => {}, //~ ERROR unreachable pattern
  55     }
  56 }
  57
  58 fn empty_foreign_enum(x: empty::EmptyForeignEnum) {
  59     match x {} // ok
  60     match x {
  61         _ => {}, //~ ERROR unreachable pattern
  62     }
  63     match x {
  64         _ if false => {}, //~ ERROR unreachable pattern
  65     }
  66 }
  67
  68 fn never(x: !) {
  69     match x {} // ok
  70     match x {
  71         _ => {}, //~ ERROR unreachable pattern
  72     }
  73     match x {
  74         _ if false => {}, //~ ERROR unreachable pattern
  75     }
  76 }
  77
  78 fn main() {
  79     // `exhaustive_patterns` is not on, so uninhabited branches are not detected as unreachable.
  80     match None::<!> {
  81         None => {}
  82         Some(_) => {}
  83     }
  84     match None::<EmptyEnum> {
  85         None => {}
  86         Some(_) => {}
  87     }
  88
  89     match_empty!(0u8);
  90     //~^ ERROR type `u8` is non-empty
  91     match_empty!(NonEmptyStruct(true));
  92     //~^ ERROR type `NonEmptyStruct` is non-empty
  93     match_empty!((NonEmptyUnion1 { foo: () }));
  94     //~^ ERROR type `NonEmptyUnion1` is non-empty
  95     match_empty!((NonEmptyUnion2 { foo: () }));
  96     //~^ ERROR type `NonEmptyUnion2` is non-empty
  97     match_empty!(NonEmptyEnum1::Foo(true));
  98     //~^ ERROR `Foo(_)` not covered
  99     match_empty!(NonEmptyEnum2::Foo(true));
 100     //~^ ERROR `Foo(_)` and `Bar` not covered
 101     match_empty!(NonEmptyEnum5::V1);
 102     //~^ ERROR `V1`, `V2`, `V3` and 2 more not covered
 103
 104     match_false!(0u8);
 105     //~^ ERROR `_` not covered
 106     match_false!(NonEmptyStruct(true));
 107     //~^ ERROR `NonEmptyStruct(_)` not covered
 108     match_false!((NonEmptyUnion1 { foo: () }));
 109     //~^ ERROR `NonEmptyUnion1 { .. }` not covered
 110     match_false!((NonEmptyUnion2 { foo: () }));
 111     //~^ ERROR `NonEmptyUnion2 { .. }` not covered
 112     match_false!(NonEmptyEnum1::Foo(true));
 113     //~^ ERROR `Foo(_)` not covered
 114     match_false!(NonEmptyEnum2::Foo(true));
 115     //~^ ERROR `Foo(_)` and `Bar` not covered
 116     match_false!(NonEmptyEnum5::V1);
 117     //~^ ERROR `V1`, `V2`, `V3` and 2 more not covered
 118 }