crates/ide/src/inlay_hints/implicit_static.rs

   1 //! Implementation of "implicit static" inlay hints:
   2 //! ```no_run
   3 //! static S: &/* 'static */str = "";
   4 //! ```
   5 use either::Either;
   6 use syntax::{
   7     ast::{self, AstNode},
   8     SyntaxKind,
   9 };
  10
  11 use crate::{InlayHint, InlayHintsConfig, InlayKind, InlayTooltip, LifetimeElisionHints};
  12
  13 pub(super) fn hints(
  14     acc: &mut Vec<InlayHint>,
  15     config: &InlayHintsConfig,
  16     statik_or_const: Either<ast::Static, ast::Const>,
  17 ) -> Option<()> {
  18     if config.lifetime_elision_hints != LifetimeElisionHints::Always {
  19         return None;
  20     }
  21
  22     if let Either::Right(it) = &statik_or_const {
  23         if ast::AssocItemList::can_cast(
  24             it.syntax().parent().map_or(SyntaxKind::EOF, |it| it.kind()),
  25         ) {
  26             return None;
  27         }
  28     }
  29
  30     if let Some(ast::Type::RefType(ty)) = statik_or_const.either(|it| it.ty(), |it| it.ty()) {
  31         if ty.lifetime().is_none() {
  32             let t = ty.amp_token()?;
  33             acc.push(InlayHint {
  34                 range: t.text_range(),
  35                 kind: InlayKind::LifetimeHint,
  36                 label: "'static".to_owned().into(),
  37                 tooltip: Some(InlayTooltip::String("Elided static lifetime".into())),
  38             });
  39         }
  40     }
  41
  42     Some(())
  43 }
  44
  45 #[cfg(test)]
  46 mod tests {
  47     use crate::{
  48         inlay_hints::tests::{check_with_config, TEST_CONFIG},
  49         InlayHintsConfig, LifetimeElisionHints,
  50     };
  51
  52     #[test]
  53     fn hints_lifetimes_static() {
  54         check_with_config(
  55             InlayHintsConfig {
  56                 lifetime_elision_hints: LifetimeElisionHints::Always,
  57                 ..TEST_CONFIG
  58             },
  59             r#"
  60 trait Trait {}
  61 static S: &str = "";
  62 //        ^'static
  63 const C: &str = "";
  64 //       ^'static
  65 const C: &dyn Trait = panic!();
  66 //       ^'static
  67
  68 impl () {
  69     const C: &str = "";
  70     const C: &dyn Trait = panic!();
  71 }
  72 "#,
  73         );
  74     }
  75 }