src/tools/rust-analyzer/crates/ide/src/inlay_hints/closure_ret.rs

   1 //! Implementation of "closure return type" inlay hints.
   2 use ide_db::{base_db::FileId, famous_defs::FamousDefs};
   3 use syntax::ast::{self, AstNode};
   4
   5 use crate::{
   6     inlay_hints::closure_has_block_body, ClosureReturnTypeHints, InlayHint, InlayHintsConfig,
   7     InlayKind, InlayTooltip,
   8 };
   9
  10 use super::label_of_ty;
  11
  12 pub(super) fn hints(
  13     acc: &mut Vec<InlayHint>,
  14     famous_defs @ FamousDefs(sema, _): &FamousDefs<'_, '_>,
  15     config: &InlayHintsConfig,
  16     file_id: FileId,
  17     closure: ast::ClosureExpr,
  18 ) -> Option<()> {
  19     if config.closure_return_type_hints == ClosureReturnTypeHints::Never {
  20         return None;
  21     }
  22
  23     if closure.ret_type().is_some() {
  24         return None;
  25     }
  26
  27     if !closure_has_block_body(&closure)
  28         && config.closure_return_type_hints == ClosureReturnTypeHints::WithBlock
  29     {
  30         return None;
  31     }
  32
  33     let param_list = closure.param_list()?;
  34
  35     let closure = sema.descend_node_into_attributes(closure).pop()?;
  36     let ty = sema.type_of_expr(&ast::Expr::ClosureExpr(closure))?.adjusted();
  37     let callable = ty.as_callable(sema.db)?;
  38     let ty = callable.return_type();
  39     if ty.is_unit() {
  40         return None;
  41     }
  42     acc.push(InlayHint {
  43         range: param_list.syntax().text_range(),
  44         kind: InlayKind::ClosureReturnTypeHint,
  45         label: label_of_ty(famous_defs, config, ty)?,
  46         tooltip: Some(InlayTooltip::HoverRanged(file_id, param_list.syntax().text_range())),
  47     });
  48     Some(())
  49 }