crates/ide_completion/src/completions/attribute/derive.rs

   1 //! Completion for derives
   2 use hir::{HasAttrs, MacroDef, MacroKind};
   3 use ide_db::helpers::{import_assets::ImportAssets, insert_use::ImportScope, FamousDefs};
   4 use itertools::Itertools;
   5 use rustc_hash::FxHashSet;
   6 use syntax::{ast, SyntaxKind};
   7
   8 use crate::{
   9     completions::flyimport::compute_fuzzy_completion_order_key,
  10     context::CompletionContext,
  11     item::{CompletionItem, CompletionItemKind},
  12     Completions, ImportEdit,
  13 };
  14
  15 pub(super) fn complete_derive(
  16     acc: &mut Completions,
  17     ctx: &CompletionContext,
  18     existing_derives: &[ast::Path],
  19 ) {
  20     let core = FamousDefs(&ctx.sema, ctx.krate).core();
  21     let existing_derives: FxHashSet<_> = existing_derives
  22         .into_iter()
  23         .filter_map(|path| ctx.scope.speculative_resolve_as_mac(&path))
  24         .filter(|mac| mac.kind() == MacroKind::Derive)
  25         .collect();
  26
  27     for (name, mac) in get_derives_in_scope(ctx) {
  28         if existing_derives.contains(&mac) {
  29             continue;
  30         }
  31
  32         let name = name.to_smol_str();
  33         let label;
  34         let (label, lookup) = match core.zip(mac.module(ctx.db).map(|it| it.krate())) {
  35             // show derive dependencies for `core`/`std` derives
  36             Some((core, mac_krate)) if core == mac_krate => {
  37                 if let Some(derive_completion) = DEFAULT_DERIVE_DEPENDENCIES
  38                     .iter()
  39                     .find(|derive_completion| derive_completion.label == name)
  40                 {
  41                     let mut components = vec![derive_completion.label];
  42                     components.extend(derive_completion.dependencies.iter().filter(
  43                         |&&dependency| {
  44                             !existing_derives
  45                                 .iter()
  46                                 .filter_map(|it| it.name(ctx.db))
  47                                 .any(|it| it.to_smol_str() == dependency)
  48                         },
  49                     ));
  50                     let lookup = components.join(", ");
  51                     label = components.iter().rev().join(", ");
  52                     (label.as_str(), Some(lookup))
  53                 } else {
  54                     (&*name, None)
  55                 }
  56             }
  57             _ => (&*name, None),
  58         };
  59
  60         let mut item =
  61             CompletionItem::new(CompletionItemKind::Attribute, ctx.source_range(), label);
  62         if let Some(docs) = mac.docs(ctx.db) {
  63             item.documentation(docs);
  64         }
  65         if let Some(lookup) = lookup {
  66             item.lookup_by(lookup);
  67         }
  68         item.add_to(acc);
  69     }
  70
  71     flyimport_attribute(ctx, acc);
  72 }
  73
  74 fn get_derives_in_scope(ctx: &CompletionContext) -> Vec<(hir::Name, MacroDef)> {
  75     let mut result = Vec::default();
  76     ctx.process_all_names(&mut |name, scope_def| {
  77         if let hir::ScopeDef::MacroDef(mac) = scope_def {
  78             if mac.kind() == hir::MacroKind::Derive {
  79                 result.push((name, mac));
  80             }
  81         }
  82     });
  83     result
  84 }
  85
  86 fn flyimport_attribute(ctx: &CompletionContext, acc: &mut Completions) -> Option<()> {
  87     if ctx.token.kind() != SyntaxKind::IDENT {
  88         return None;
  89     };
  90     let potential_import_name = ctx.token.to_string();
  91     let module = ctx.scope.module()?;
  92     let parent = ctx.token.parent()?;
  93     let user_input_lowercased = potential_import_name.to_lowercase();
  94     let import_assets = ImportAssets::for_fuzzy_path(
  95         module,
  96         None,
  97         potential_import_name,
  98         &ctx.sema,
  99         parent.clone(),
 100     )?;
 101     let import_scope = ImportScope::find_insert_use_container(&parent, &ctx.sema)?;
 102     acc.add_all(
 103         import_assets
 104             .search_for_imports(&ctx.sema, ctx.config.insert_use.prefix_kind)
 105             .into_iter()
 106             .filter_map(|import| match import.original_item {
 107                 hir::ItemInNs::Macros(mac) => Some((import, mac)),
 108                 _ => None,
 109             })
 110             .filter(|&(_, mac)| !ctx.is_item_hidden(&hir::ItemInNs::Macros(mac)))
 111             .sorted_by_key(|(import, _)| {
 112                 compute_fuzzy_completion_order_key(&import.import_path, &user_input_lowercased)
 113             })
 114             .filter_map(|(import, mac)| {
 115                 let mut item = CompletionItem::new(
 116                     CompletionItemKind::Attribute,
 117                     ctx.source_range(),
 118                     mac.name(ctx.db)?.to_string(),
 119                 );
 120                 item.add_import(ImportEdit { import, scope: import_scope.clone() });
 121                 if let Some(docs) = mac.docs(ctx.db) {
 122                     item.documentation(docs);
 123                 }
 124                 Some(item.build())
 125             }),
 126     );
 127     Some(())
 128 }
 129
 130 struct DeriveDependencies {
 131     label: &'static str,
 132     dependencies: &'static [&'static str],
 133 }
 134
 135 /// Standard Rust derives that have dependencies
 136 /// (the dependencies are needed so that the main derive don't break the compilation when added)
 137 const DEFAULT_DERIVE_DEPENDENCIES: &[DeriveDependencies] = &[
 138     DeriveDependencies { label: "Copy", dependencies: &["Clone"] },
 139     DeriveDependencies { label: "Eq", dependencies: &["PartialEq"] },
 140     DeriveDependencies { label: "Ord", dependencies: &["PartialOrd", "Eq", "PartialEq"] },
 141     DeriveDependencies { label: "PartialOrd", dependencies: &["PartialEq"] },
 142 ];