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

   1 //! Completion for derives
   2 use hir::{HasAttrs, MacroDef, MacroKind};
   3 use ide_db::{
   4     helpers::{import_assets::ImportAssets, insert_use::ImportScope},
   5     SymbolKind,
   6 };
   7 use itertools::Itertools;
   8 use rustc_hash::FxHashSet;
   9 use syntax::{ast, SmolStr, SyntaxKind};
  10
  11 use crate::{
  12     completions::flyimport::compute_fuzzy_completion_order_key, context::CompletionContext,
  13     item::CompletionItem, Completions, ImportEdit,
  14 };
  15
  16 pub(super) fn complete_derive(
  17     acc: &mut Completions,
  18     ctx: &CompletionContext,
  19     existing_derives: &[ast::Path],
  20 ) {
  21     let core = ctx.famous_defs().core();
  22     let existing_derives: FxHashSet<_> = existing_derives
  23         .into_iter()
  24         .filter_map(|path| ctx.scope.speculative_resolve_as_mac(&path))
  25         .filter(|mac| mac.kind() == MacroKind::Derive)
  26         .collect();
  27
  28     for (name, mac) in get_derives_in_scope(ctx) {
  29         if existing_derives.contains(&mac) {
  30             continue;
  31         }
  32
  33         let name = name.to_smol_str();
  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                     let label = Itertools::intersperse(components.into_iter().rev(), ", ");
  52                     (SmolStr::from_iter(label), Some(lookup))
  53                 } else {
  54                     (name, None)
  55                 }
  56             }
  57             _ => (name, None),
  58         };
  59
  60         let mut item = CompletionItem::new(SymbolKind::Derive, ctx.source_range(), label);
  61         if let Some(docs) = mac.docs(ctx.db) {
  62             item.documentation(docs);
  63         }
  64         if let Some(lookup) = lookup {
  65             item.lookup_by(lookup);
  66         }
  67         item.add_to(acc);
  68     }
  69
  70     flyimport_derive(acc, ctx);
  71 }
  72
  73 fn get_derives_in_scope(ctx: &CompletionContext) -> Vec<(hir::Name, MacroDef)> {
  74     let mut result = Vec::default();
  75     ctx.process_all_names(&mut |name, scope_def| {
  76         if let hir::ScopeDef::MacroDef(mac) = scope_def {
  77             if mac.kind() == hir::MacroKind::Derive {
  78                 result.push((name, mac));
  79             }
  80         }
  81     });
  82     result
  83 }
  84
  85 fn flyimport_derive(acc: &mut Completions, ctx: &CompletionContext) -> Option<()> {
  86     if ctx.token.kind() != SyntaxKind::IDENT {
  87         return None;
  88     };
  89     let potential_import_name = ctx.token.to_string();
  90     let module = ctx.scope.module()?;
  91     let parent = ctx.token.parent()?;
  92     let user_input_lowercased = potential_import_name.to_lowercase();
  93     let import_assets = ImportAssets::for_fuzzy_path(
  94         module,
  95         None,
  96         potential_import_name,
  97         &ctx.sema,
  98         parent.clone(),
  99     )?;
 100     let import_scope = ImportScope::find_insert_use_container(&parent, &ctx.sema)?;
 101     acc.add_all(
 102         import_assets
 103             .search_for_imports(&ctx.sema, ctx.config.insert_use.prefix_kind)
 104             .into_iter()
 105             .filter_map(|import| match import.original_item {
 106                 hir::ItemInNs::Macros(mac) => Some((import, mac)),
 107                 _ => None,
 108             })
 109             .filter(|&(_, mac)| mac.kind() == MacroKind::Derive)
 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                     SymbolKind::Derive,
 117                     ctx.source_range(),
 118                     mac.name(ctx.db)?.to_smol_str(),
 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 ];