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

   1 // run-rustfix
   2 #![warn(clippy::trim_split_whitespace)]
   3 #![allow(clippy::let_unit_value)]
   4
   5 struct Custom;
   6 impl Custom {
   7     fn trim(self) -> Self {
   8         self
   9     }
  10     fn split_whitespace(self) {}
  11 }
  12
  13 struct DerefStr(&'static str);
  14 impl std::ops::Deref for DerefStr {
  15     type Target = str;
  16     fn deref(&self) -> &Self::Target {
  17         self.0
  18     }
  19 }
  20
  21 struct DerefStrAndCustom(&'static str);
  22 impl std::ops::Deref for DerefStrAndCustom {
  23     type Target = str;
  24     fn deref(&self) -> &Self::Target {
  25         self.0
  26     }
  27 }
  28 impl DerefStrAndCustom {
  29     fn trim(self) -> Self {
  30         self
  31     }
  32     fn split_whitespace(self) {}
  33 }
  34
  35 struct DerefStrAndCustomSplit(&'static str);
  36 impl std::ops::Deref for DerefStrAndCustomSplit {
  37     type Target = str;
  38     fn deref(&self) -> &Self::Target {
  39         self.0
  40     }
  41 }
  42 impl DerefStrAndCustomSplit {
  43     #[allow(dead_code)]
  44     fn split_whitespace(self) {}
  45 }
  46
  47 struct DerefStrAndCustomTrim(&'static str);
  48 impl std::ops::Deref for DerefStrAndCustomTrim {
  49     type Target = str;
  50     fn deref(&self) -> &Self::Target {
  51         self.0
  52     }
  53 }
  54 impl DerefStrAndCustomTrim {
  55     fn trim(self) -> Self {
  56         self
  57     }
  58 }
  59
  60 fn main() {
  61     // &str
  62     let _ = " A B C ".trim().split_whitespace(); // should trigger lint
  63     let _ = " A B C ".trim_start().split_whitespace(); // should trigger lint
  64     let _ = " A B C ".trim_end().split_whitespace(); // should trigger lint
  65
  66     // String
  67     let _ = (" A B C ").to_string().trim().split_whitespace(); // should trigger lint
  68     let _ = (" A B C ").to_string().trim_start().split_whitespace(); // should trigger lint
  69     let _ = (" A B C ").to_string().trim_end().split_whitespace(); // should trigger lint
  70
  71     // Custom
  72     let _ = Custom.trim().split_whitespace(); // should not trigger lint
  73
  74     // Deref<Target=str>
  75     let s = DerefStr(" A B C ");
  76     let _ = s.trim().split_whitespace(); // should trigger lint
  77
  78     // Deref<Target=str> + custom impl
  79     let s = DerefStrAndCustom(" A B C ");
  80     let _ = s.trim().split_whitespace(); // should not trigger lint
  81
  82     // Deref<Target=str> + only custom split_ws() impl
  83     let s = DerefStrAndCustomSplit(" A B C ");
  84     let _ = s.trim().split_whitespace(); // should trigger lint
  85     // Expl: trim() is called on str (deref) and returns &str.
  86     //       Thus split_ws() is called on str as well and the custom impl on S is unused
  87
  88     // Deref<Target=str> + only custom trim() impl
  89     let s = DerefStrAndCustomTrim(" A B C ");
  90     let _ = s.trim().split_whitespace(); // should not trigger lint
  91 }