Use natural trait ordering in derive completion

derive(Clone, Copy) reads better than derive(Copy, Clone).

However, we preserve the reverse ordering in the lookup text for
sorting purposes. That way, it's convenient to type just `Ord` to
derive everything.

2 files changed, 18 insertions, 136 deletions

diff --git a/crates/completion/src/completions/attribute.rs b/crates/completion/src/completions/attribute.rs
index 5404145d5..acce2e7e7 100644
--- a/crates/completion/src/completions/attribute.rs
+++ b/crates/completion/src/completions/attribute.rs
@@ -3,6 +3,7 @@
 //! This module uses a bit of static metadata to provide completions
 //! for built-in attributes.
 
+use itertools::Itertools;
 use rustc_hash::FxHashSet;
 use syntax::{ast, AstNode, SyntaxKind};
 
@@ -162,19 +163,20 @@ const ATTRIBUTES: &[AttrCompletion] = &[
 fn complete_derive(acc: &mut Completions, ctx: &CompletionContext, derive_input: ast::TokenTree) {
     if let Ok(existing_derives) = parse_comma_sep_input(derive_input) {
         for derive_completion in DEFAULT_DERIVE_COMPLETIONS
-            .into_iter()
+            .iter()
             .filter(|completion| !existing_derives.contains(completion.label))
         {
-            let mut label = derive_completion.label.to_owned();
-            for dependency in derive_completion
-                .dependencies
-                .into_iter()
-                .filter(|&&dependency| !existing_derives.contains(dependency))
-            {
-                label.push_str(", ");
-                label.push_str(dependency);
-            }
+            let mut components = vec![derive_completion.label];
+            components.extend(
+                derive_completion
+                    .dependencies
+                    .iter()
+                    .filter(|&&dependency| !existing_derives.contains(dependency)),
+            );
+            let lookup = components.join(", ");
+            let label = components.iter().rev().join(", ");
             CompletionItem::new(CompletionKind::Attribute, ctx.source_range(), label)
+                .lookup_by(lookup)
                 .kind(CompletionItemKind::Attribute)
                 .add_to(acc)
         }
@@ -264,7 +266,6 @@ struct DeriveCompletion {
 
 /// Standard Rust derives and the information about their dependencies
 /// (the dependencies are needed so that the main derive don't break the compilation when added)
-#[rustfmt::skip]
 const DEFAULT_DERIVE_COMPLETIONS: &[DeriveCompletion] = &[
     DeriveCompletion { label: "Clone", dependencies: &[] },
     DeriveCompletion { label: "Copy", dependencies: &["Clone"] },
@@ -421,14 +422,14 @@ struct Test {}
         "#,
             expect![[r#"
                 at Clone
-                at Copy, Clone
+                at Clone, Copy
                 at Debug
                 at Default
-                at Eq, PartialEq
                 at Hash
-                at Ord, PartialOrd, Eq, PartialEq
                 at PartialEq
-                at PartialOrd, PartialEq
+                at PartialEq, Eq
+                at PartialEq, Eq, PartialOrd, Ord
+                at PartialEq, PartialOrd
             "#]],
         );
     }
@@ -453,12 +454,12 @@ struct Test {}
 "#,
             expect![[r#"
                 at Clone
-                at Copy, Clone
+                at Clone, Copy
                 at Debug
                 at Default
                 at Eq
+                at Eq, PartialOrd, Ord
                 at Hash
-                at Ord, PartialOrd, Eq
                 at PartialOrd
             "#]],
         )
diff --git a/docs/user/generated_diagnostic.adoc b/docs/user/generated_diagnostic.adoc
deleted file mode 100644
index ec8581a03..000000000
--- a/docs/user/generated_diagnostic.adoc
+++ /dev/null
@@ -1,119 +0,0 @@
-//Generated file, do not edit by hand, see `xtask/src/codegen`
-=== break-outside-of-loop
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_ty/src/diagnostics.rs#L219[diagnostics.rs]
-
-This diagnostic is triggered if `break` keyword is used outside of a loop.
-
-
-=== inactive-code
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_def/src/diagnostics.rs#L98[diagnostics.rs]
-
-This diagnostic is shown for code with inactive `#[cfg]` attributes.
-
-
-=== incorrect-ident-case
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_ty/src/diagnostics.rs#L319[diagnostics.rs]
-
-This diagnostic is triggered if item name doesn't follow https://doc.rust-lang.org/1.0.0/style/style/naming/README.html[Rust naming convention].
-
-
-=== macro-error
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_def/src/diagnostics.rs#L167[diagnostics.rs]
-
-This diagnostic is shown for macro expansion errors.
-
-
-=== mismatched-arg-count
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_ty/src/diagnostics.rs#L267[diagnostics.rs]
-
-This diagnostic is triggered if function is invoked with an incorrect amount of arguments.
-
-
-=== missing-match-arm
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_ty/src/diagnostics.rs#L162[diagnostics.rs]
-
-This diagnostic is triggered if `match` block is missing one or more match arms.
-
-
-=== missing-ok-in-tail-expr
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_ty/src/diagnostics.rs#L187[diagnostics.rs]
-
-This diagnostic is triggered if block that should return `Result` returns a value not wrapped in `Ok`.
-
-Example:
-
-```rust
-fn foo() -> Result<u8, ()> {
-    10
-}
-```
-
-
-=== missing-pat-fields
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_ty/src/diagnostics.rs#L113[diagnostics.rs]
-
-This diagnostic is triggered if pattern lacks some fields that exist in the corresponding structure.
-
-Example:
-
-```rust
-struct A { a: u8, b: u8 }
-
-let a = A { a: 10, b: 20 };
-
-if let A { a } = a {
-    // ...
-}
-```
-
-
-=== missing-structure-fields
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_ty/src/diagnostics.rs#L66[diagnostics.rs]
-
-This diagnostic is triggered if record lacks some fields that exist in the corresponding structure.
-
-Example:
-
-```rust
-struct A { a: u8, b: u8 }
-
-let a = A { a: 10 };
-```
-
-
-=== missing-unsafe
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_ty/src/diagnostics.rs#L243[diagnostics.rs]
-
-This diagnostic is triggered if operation marked as `unsafe` is used outside of `unsafe` function or block.
-
-
-=== no-such-field
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_ty/src/diagnostics.rs#L39[diagnostics.rs]
-
-This diagnostic is triggered if created structure does not have field provided in record.
-
-
-=== unresolved-extern-crate
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_def/src/diagnostics.rs#L43[diagnostics.rs]
-
-This diagnostic is triggered if rust-analyzer is unable to discover referred extern crate.
-
-
-=== unresolved-import
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_def/src/diagnostics.rs#L67[diagnostics.rs]
-
-This diagnostic is triggered if rust-analyzer is unable to discover imported module.
-
-
-=== unresolved-module
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_def/src/diagnostics.rs#L18[diagnostics.rs]
-
-This diagnostic is triggered if rust-analyzer is unable to discover referred module.
-
-
-=== unresolved-proc-macro
-**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/hir_def/src/diagnostics.rs#L131[diagnostics.rs]
-
-This diagnostic is shown when a procedural macro can not be found. This usually means that
-procedural macro support is simply disabled (and hence is only a weak hint instead of an error),
-but can also indicate project setup problems.