src/tools/clippy/tests/ui/unnecessary_operation.rs

   1 // run-rustfix
   2
   3 #![feature(box_syntax)]
   4 #![allow(clippy::deref_addrof, dead_code, unused, clippy::no_effect)]
   5 #![warn(clippy::unnecessary_operation)]
   6
   7 struct Tuple(i32);
   8 struct Struct {
   9     field: i32,
  10 }
  11 enum Enum {
  12     Tuple(i32),
  13     Struct { field: i32 },
  14 }
  15 struct DropStruct {
  16     field: i32,
  17 }
  18 impl Drop for DropStruct {
  19     fn drop(&mut self) {}
  20 }
  21 struct DropTuple(i32);
  22 impl Drop for DropTuple {
  23     fn drop(&mut self) {}
  24 }
  25 enum DropEnum {
  26     Tuple(i32),
  27     Struct { field: i32 },
  28 }
  29 impl Drop for DropEnum {
  30     fn drop(&mut self) {}
  31 }
  32 struct FooString {
  33     s: String,
  34 }
  35
  36 fn get_number() -> i32 {
  37     0
  38 }
  39
  40 fn get_usize() -> usize {
  41     0
  42 }
  43 fn get_struct() -> Struct {
  44     Struct { field: 0 }
  45 }
  46 fn get_drop_struct() -> DropStruct {
  47     DropStruct { field: 0 }
  48 }
  49
  50 fn main() {
  51     Tuple(get_number());
  52     Struct { field: get_number() };
  53     Struct { ..get_struct() };
  54     Enum::Tuple(get_number());
  55     Enum::Struct { field: get_number() };
  56     5 + get_number();
  57     *&get_number();
  58     &get_number();
  59     (5, 6, get_number());
  60     box get_number();
  61     get_number()..;
  62     ..get_number();
  63     5..get_number();
  64     [42, get_number()];
  65     [42, 55][get_usize()];
  66     (42, get_number()).1;
  67     [get_number(); 55];
  68     [42; 55][get_usize()];
  69     {
  70         get_number()
  71     };
  72     FooString {
  73         s: String::from("blah"),
  74     };
  75
  76     // Do not warn
  77     DropTuple(get_number());
  78     DropStruct { field: get_number() };
  79     DropStruct { field: get_number() };
  80     DropStruct { ..get_drop_struct() };
  81     DropEnum::Tuple(get_number());
  82     DropEnum::Struct { field: get_number() };
  83
  84     // Issue #9954
  85     fn one() -> i8 {
  86         1
  87     }
  88     macro_rules! use_expr {
  89         ($($e:expr),*) => {{ $($e;)* }}
  90     }
  91     use_expr!(isize::MIN / -(one() as isize), i8::MIN / -one());
  92 }