crates/ra_assists/src/handlers/flip_comma.rs

   1 use ra_syntax::{algo::non_trivia_sibling, Direction, T};
   2
   3 use crate::{Assist, AssistCtx, AssistId};
   4
   5 // Assist: flip_comma
   6 //
   7 // Flips two comma-separated items.
   8 //
   9 // ```
  10 // fn main() {
  11 //     ((1, 2),<|> (3, 4));
  12 // }
  13 // ```
  14 // ->
  15 // ```
  16 // fn main() {
  17 //     ((3, 4), (1, 2));
  18 // }
  19 // ```
  20 pub(crate) fn flip_comma(ctx: AssistCtx) -> Option<Assist> {
  21     let comma = ctx.find_token_at_offset(T![,])?;
  22     let prev = non_trivia_sibling(comma.clone().into(), Direction::Prev)?;
  23     let next = non_trivia_sibling(comma.clone().into(), Direction::Next)?;
  24
  25     // Don't apply a "flip" in case of a last comma
  26     // that typically comes before punctuation
  27     if next.kind().is_punct() {
  28         return None;
  29     }
  30
  31     ctx.add_assist(AssistId("flip_comma"), "Flip comma", |edit| {
  32         edit.target(comma.text_range());
  33         edit.replace(prev.text_range(), next.to_string());
  34         edit.replace(next.text_range(), prev.to_string());
  35     })
  36 }
  37
  38 #[cfg(test)]
  39 mod tests {
  40     use super::*;
  41
  42     use crate::tests::{check_assist, check_assist_target};
  43
  44     #[test]
  45     fn flip_comma_works_for_function_parameters() {
  46         check_assist(
  47             flip_comma,
  48             "fn foo(x: i32,<|> y: Result<(), ()>) {}",
  49             "fn foo(y: Result<(), ()>,<|> x: i32) {}",
  50         )
  51     }
  52
  53     #[test]
  54     fn flip_comma_target() {
  55         check_assist_target(flip_comma, "fn foo(x: i32,<|> y: Result<(), ()>) {}", ",")
  56     }
  57
  58     #[test]
  59     #[should_panic]
  60     fn flip_comma_before_punct() {
  61         // See https://github.com/rust-analyzer/rust-analyzer/issues/1619
  62         // "Flip comma" assist shouldn't be applicable to the last comma in enum or struct
  63         // declaration body.
  64         check_assist_target(
  65             flip_comma,
  66             "pub enum Test { \
  67              A,<|> \
  68              }",
  69             ",",
  70         );
  71
  72         check_assist_target(
  73             flip_comma,
  74             "pub struct Test { \
  75              foo: usize,<|> \
  76              }",
  77             ",",
  78         );
  79     }
  80 }