refactor add_keywords in ide-completions for clarity

Author: roife

src/tools/rust-analyzer/crates/ide-completion/src/completions/item_list.rs

@@ -75,73 +75,82 @@ fn add_keywords(acc: &mut Completions, ctx: &CompletionContext<'_>, kind: Option
 
     let in_item_list = matches!(kind, Some(ItemListKind::SourceFile | ItemListKind::Module) | None);
     let in_assoc_non_trait_impl = matches!(kind, Some(ItemListKind::Impl | ItemListKind::Trait));
+
     let in_extern_block = matches!(kind, Some(ItemListKind::ExternBlock));
     let in_trait = matches!(kind, Some(ItemListKind::Trait));
     let in_trait_impl = matches!(kind, Some(ItemListKind::TraitImpl(_)));
     let in_inherent_impl = matches!(kind, Some(ItemListKind::Impl));
-    let no_vis_qualifiers = ctx.qualifier_ctx.vis_node.is_none();
     let in_block = kind.is_none();
 
-    let missing_qualifiers = [
-        ctx.qualifier_ctx.unsafe_tok.is_none().then_some(("unsafe", "unsafe $0")),
-        ctx.qualifier_ctx.async_tok.is_none().then_some(("async", "async $0")),
-    ];
-
-    if !in_trait_impl {
-        // handle qualifier tokens
-        if missing_qualifiers.iter().any(Option::is_none) {
-            // only complete missing qualifiers
-            missing_qualifiers.iter().filter_map(|x| *x).for_each(|(kw, snippet)| {
-                add_keyword(kw, snippet);
-            });
+    let no_vis_qualifiers = ctx.qualifier_ctx.vis_node.is_none();
+    let has_unsafe_kw = ctx.qualifier_ctx.unsafe_tok.is_some();
+    let has_async_kw = ctx.qualifier_ctx.async_tok.is_some();
 
-            if in_item_list || in_assoc_non_trait_impl {
-                add_keyword("fn", "fn $1($2) {\n    $0\n}");
-            }
+    // We handle completions for trait-impls in [`item_list::trait_impl`]
+    if in_trait_impl {
+        return;
+    }
 
-            if ctx.qualifier_ctx.unsafe_tok.is_some() && in_item_list {
-                add_keyword("trait", "trait $1 {\n    $0\n}");
-                if no_vis_qualifiers {
-                    add_keyword("impl", "impl $1 {\n    $0\n}");
-                }
-            }
+    // Some keywords are invalid after non-vis qualifiers, so we handle them first.
+    if has_unsafe_kw || has_async_kw {
+        if !has_unsafe_kw {
+            add_keyword("unsafe", "unsafe $0");
+        }
+        if !has_async_kw {
+            add_keyword("async", "async $0");
+        }
 
-            return;
+        if in_item_list || in_assoc_non_trait_impl {
+            add_keyword("fn", "fn $1($2) {\n    $0\n}");
         }
 
-        if in_item_list {
-            add_keyword("enum", "enum $1 {\n    $0\n}");
-            add_keyword("mod", "mod $0");
-            add_keyword("static", "static $0");
-            add_keyword("struct", "struct $0");
+        if has_unsafe_kw && in_item_list {
             add_keyword("trait", "trait $1 {\n    $0\n}");
-            add_keyword("union", "union $1 {\n    $0\n}");
-            add_keyword("use", "use $0");
             if no_vis_qualifiers {
                 add_keyword("impl", "impl $1 {\n    $0\n}");
             }
         }
 
-        if !in_trait && !in_block && no_vis_qualifiers {
-            add_keyword("pub(crate)", "pub(crate) $0");
-            add_keyword("pub(super)", "pub(super) $0");
-            add_keyword("pub", "pub $0");
+        return;
+    }
+
+    // ...and the rest deals with cases without any non-vis qualifiers.
+
+    // Visibility qualifiers
+    if !in_trait && !in_block && no_vis_qualifiers {
+        add_keyword("pub(crate)", "pub(crate) $0");
+        add_keyword("pub(super)", "pub(super) $0");
+        add_keyword("pub", "pub $0");
+    }
+
+    // Keywords that are valid in `item_list`
+    if in_item_list {
+        add_keyword("enum", "enum $1 {\n    $0\n}");
+        add_keyword("mod", "mod $0");
+        add_keyword("static", "static $0");
+        add_keyword("struct", "struct $0");
+        add_keyword("trait", "trait $1 {\n    $0\n}");
+        add_keyword("union", "union $1 {\n    $0\n}");
+        add_keyword("use", "use $0");
+        if no_vis_qualifiers {
+            add_keyword("impl", "impl $1 {\n    $0\n}");
         }
+    }
 
-        if in_extern_block {
-            add_keyword("fn", "fn $1($2);");
-        } else {
-            if !in_inherent_impl {
-                if !in_trait {
-                    add_keyword("extern", "extern $0");
-                }
-                add_keyword("type", "type $0");
+    if in_extern_block {
+        add_keyword("fn", "fn $1($2);");
+        add_keyword("static", "static $1: $2;");
+    } else {
+        if !in_inherent_impl {
+            if !in_trait {
+                add_keyword("extern", "extern $0");
             }
-
-            add_keyword("fn", "fn $1($2) {\n    $0\n}");
-            add_keyword("unsafe", "unsafe $0");
-            add_keyword("const", "const $0");
-            add_keyword("async", "async $0");
+            add_keyword("type", "type $0");
         }
+
+        add_keyword("fn", "fn $1($2) {\n    $0\n}");
+        add_keyword("unsafe", "unsafe $0");
+        add_keyword("const", "const $0");
+        add_keyword("async", "async $0");
     }
 }