Merge #4664

4664: Generate feature documentation from code r=matklad a=matklad



Co-authored-by: Aleksey Kladov <aleksey.kladov@gmail.com>

4 files changed, 327 insertions, 220 deletions

diff --git a/docs/user/assists.md b/docs/user/assists.md
index a1058ecde97..04387e3b0ee 100644
--- a/docs/user/assists.md
+++ b/docs/user/assists.md
@@ -56,6 +56,24 @@ fn main() {
 }
 ```
 
+## `add_from_impl_for_enum`
+
+Adds a From impl for an enum variant with one tuple field.
+
+```rust
+// BEFORE
+enum A { ┃One(u32) }
+
+// AFTER
+enum A { One(u32) }
+
+impl From<u32> for A {
+    fn from(v: u32) -> Self {
+        A::One(v)
+    }
+}
+```
+
 ## `add_function`
 
 Adds a stub function with a signature matching the function under the cursor.
diff --git a/docs/user/features.md b/docs/user/features.md
deleted file mode 100644
index 12ecdec136a..00000000000
--- a/docs/user/features.md
+++ /dev/null
@@ -1,218 +0,0 @@
-This document is an index of features that the rust-analyzer language server
-provides. Shortcuts are for the default VS Code layout. If there's no shortcut,
-you can use <kbd>Ctrl+Shift+P</kbd> to search for the corresponding action.
-
-### Workspace Symbol <kbd>ctrl+t</kbd>
-
-Uses fuzzy-search to find types, modules and functions by name across your
-project and dependencies. This is **the** most useful feature, which improves code
-navigation tremendously. It mostly works on top of the built-in LSP
-functionality, however `#` and `*` symbols can be used to narrow down the
-search. Specifically,
-
-- `Foo` searches for `Foo` type in the current workspace
-- `foo#` searches for `foo` function in the current workspace
-- `Foo*` searches for `Foo` type among dependencies, including `stdlib`
-- `foo#*` searches for `foo` function among dependencies
-
-That is, `#` switches from "types" to all symbols, `*` switches from the current
-workspace to dependencies.
-
-### Document Symbol <kbd>ctrl+shift+o</kbd>
-
-Provides a tree of the symbols defined in the file. Can be used to
-
-* fuzzy search symbol in a file (super useful)
-* draw breadcrumbs to describe the context around the cursor
-* draw outline of the file
-
-### On Typing Assists
-
-Some features trigger on typing certain characters:
-
-- typing `let =` tries to smartly add `;` if `=` is followed by an existing expression
-- Enter inside comments automatically inserts `///`
-- typing `.` in a chain method call auto-indents
-
-### Extend Selection
-
-Extends the current selection to the encompassing syntactic construct
-(expression, statement, item, module, etc). It works with multiple cursors. This
-is a relatively new feature of LSP:
-https://github.com/Microsoft/language-server-protocol/issues/613, check your
-editor's LSP library to see if this feature is supported.
-
-### Go to Definition
-
-Navigates to the definition of an identifier.
-
-### Go to Implementation
-
-Navigates to the impl block of structs, enums or traits. Also implemented as a code lens.
-
-### Go to Type Defintion
-
-Navigates to the type of an identifier.
-
-### Commands <kbd>ctrl+shift+p</kbd>
-
-#### Run
-
-Shows a popup suggesting to run a test/benchmark/binary **at the current cursor
-location**. Super useful for repeatedly running just a single test. Do bind this
-to a shortcut!
-
-#### Parent Module
-
-Navigates to the parent module of the current module.
-
-#### Matching Brace
-
-If the cursor is on any brace (`<>(){}[]`) which is a part of a brace-pair,
-moves cursor to the matching brace. It uses the actual parser to determine
-braces, so it won't confuse generics with comparisons.
-
-#### Join Lines
-
-Join selected lines into one, smartly fixing up whitespace and trailing commas.
-
-#### Show Syntax Tree
-
-Shows the parse tree of the current file. It exists mostly for debugging
-rust-analyzer itself.
-
-#### Expand Macro Recursively
-
-Shows the full macro expansion of the macro at current cursor.
-
-#### Status
-
-Shows internal statistic about memory usage of rust-analyzer.
-
-#### Show RA Version
-
-Show current rust-analyzer version.
-
-#### Toggle inlay hints
-
-Toggle inlay hints view for the current workspace.
-It is recommended to assign a shortcut for this command to quickly turn off
-inlay hints when they prevent you from reading/writing the code.
-
-#### Run Garbage Collection
-
-Manually triggers GC.
-
-#### Start Cargo Watch
-
-Start `cargo watch` for live error highlighting. Will prompt to install if it's not already installed.
-
-#### Stop Cargo Watch
-
-Stop `cargo watch`.
-
-#### Structural Seach and Replace
-
-Search and replace with named wildcards that will match any expression.
-The syntax for a structural search replace command is `<search_pattern> ==>> <replace_pattern>`. A `$<name>:expr` placeholder in the search pattern will match any expression and `$<name>` will reference it in the replacement. Available via the command `rust-analyzer.ssr`.
-
-```rust
-// Using structural search replace command [foo($a:expr, $b:expr) ==>> ($a).foo($b)]
-
-// BEFORE
-String::from(foo(y + 5, z))
-
-// AFTER
-String::from((y + 5).foo(z))
-```
-
-### Assists (Code Actions)
-
-Assists, or code actions, are small local refactorings, available in a particular context.
-They are usually triggered by a shortcut or by clicking a light bulb icon in the editor.
-
-See [assists.md](./assists.md) for the list of available assists.
-
-### Magic Completions
-
-In addition to usual reference completion, rust-analyzer provides some ✨magic✨
-completions as well:
-
-Keywords like `if`, `else` `while`, `loop` are completed with braces, and cursor
-is placed at the appropriate position. Even though `if` is easy to type, you
-still want to complete it, to get ` { }` for free! `return` is inserted with a
-space or `;` depending on the return type of the function.
-
-When completing a function call, `()` are automatically inserted. If a function
-takes arguments, the cursor is positioned inside the parenthesis.
-
-There are postfix completions, which can be triggered by typing something like
-`foo().if`. The word after `.` determines postfix completion. Possible variants are:
-
-- `expr.if` -> `if expr {}` or `if let ... {}` for `Option` or `Result`
-- `expr.match` -> `match expr {}`
-- `expr.while` -> `while expr {}` or `while let ... {}` for `Option` or `Result`
-- `expr.ref` -> `&expr`
-- `expr.refm` -> `&mut expr`
-- `expr.not` -> `!expr`
-- `expr.dbg` -> `dbg!(expr)`
-
-There also snippet completions:
-
-#### Inside Expressions
-
-- `pd` -> `println!("{:?}")`
-- `ppd` -> `println!("{:#?}")`
-
-#### Inside Modules
-
-- `tfn` -> `#[test] fn f(){}`
-- `tmod` ->
-```rust
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_fn() {}
-}
-```
-
-### Code Highlighting
-
-Experimental feature to let rust-analyzer highlight Rust code instead of using the
-default highlighter.
-
-#### Rainbow Highlighting
-
-Experimental feature that, given code highlighting using rust-analyzer is
-active, will pick unique colors for identifiers.
-
-### Code hints
-
-Rust-analyzer has two types of hints to show the information about the code:
-
-* hover hints, appearing on hover on any element.
-
-These contain extended information on the hovered language item.
-
-* inlay hints, shown near the element hinted directly in the editor.
-
-Two types of inlay hints are displayed currently:
-
-* type hints, displaying the minimal information on the type of the expression (if the information is available)
-* method chaining hints, type information for multi-line method chains
-* parameter name hints, displaying the names of the parameters in the corresponding methods
-
-#### VS Code
-
-In VS Code, the following settings can be used to configure the inlay hints:
-
-* `rust-analyzer.inlayHints.typeHints` - enable hints for inferred types.
-* `rust-analyzer.inlayHints.chainingHints` - enable hints for inferred types on method chains.
-* `rust-analyzer.inlayHints.parameterHints` - enable hints for function parameters.
-* `rust-analyzer.inlayHints.maxLength` — shortens the hints if their length exceeds the value specified. If no value is specified (`null`), no shortening is applied.
-
-**Note:** VS Code does not have native support for inlay hints [yet](https://github.com/microsoft/vscode/issues/16221) and the hints are implemented using decorations.
-This approach has limitations, the caret movement and bracket highlighting near the edges of the hint may be weird:
-[1](https://github.com/rust-analyzer/rust-analyzer/issues/1623), [2](https://github.com/rust-analyzer/rust-analyzer/issues/3453).
diff --git a/docs/user/generated_features.adoc b/docs/user/generated_features.adoc
new file mode 100644
index 00000000000..803073d550f
--- /dev/null
+++ b/docs/user/generated_features.adoc
@@ -0,0 +1,298 @@
+=== Expand Macro Recursively
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/expand_macro.rs[expand_macro.rs]
+
+Shows the full macro expansion of the macro at current cursor.
+
+|===
+| Editor  | Action Name
+
+| VS Code | **Rust Analyzer: Expand macro recursively**
+|===
+
+
+=== Extend Selection
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/extend_selection.rs[extend_selection.rs]
+
+Extends the current selection to the encompassing syntactic construct
+(expression, statement, item, module, etc). It works with multiple cursors.
+
+|===
+| Editor  | Shortcut
+
+| VS Code | kbd:[Ctrl+Shift+→]
+|===
+
+
+=== File Structure
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/display/structure.rs[structure.rs]
+
+Provides a tree of the symbols defined in the file. Can be used to
+
+* fuzzy search symbol in a file (super useful)
+* draw breadcrumbs to describe the context around the cursor
+* draw outline of the file
+
+|===
+| Editor  | Shortcut
+
+| VS Code | kbd:[Ctrl+Shift+O]
+|===
+
+
+=== Go to Definition
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/goto_definition.rs[goto_definition.rs]
+
+Navigates to the definition of an identifier.
+
+|===
+| Editor  | Shortcut
+
+| VS Code | kbd:[F12]
+|===
+
+
+=== Go to Implementation
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/goto_implementation.rs[goto_implementation.rs]
+
+Navigates to the impl block of structs, enums or traits. Also implemented as a code lens.
+
+|===
+| Editor  | Shortcut
+
+| VS Code | kbd:[Ctrl+F12]
+|===
+
+
+=== Go to Type Definition
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/goto_type_definition.rs[goto_type_definition.rs]
+
+Navigates to the type of an identifier.
+
+|===
+| Editor  | Action Name
+
+| VS Code | **Go to Type Definition*
+|===
+
+
+=== Hover
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/hover.rs[hover.rs]
+
+Shows additional information, like type of an expression or documentation for definition when "focusing" code.
+Focusing is usually hovering with a mouse, but can also be triggered with a shortcut.
+
+
+=== Inlay Hints
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/inlay_hints.rs[inlay_hints.rs]
+
+rust-analyzer shows additional information inline with the source code.
+Editors usually render this using read-only virtual text snippets interspersed with code.
+
+rust-analyzer shows hits for
+
+* types of local variables
+* names of function arguments
+* types of chained expressions
+
+**Note:** VS Code does not have native support for inlay hints https://github.com/microsoft/vscode/issues/16221[yet] and the hints are implemented using decorations.
+This approach has limitations, the caret movement and bracket highlighting near the edges of the hint may be weird:
+https://github.com/rust-analyzer/rust-analyzer/issues/1623[1], https://github.com/rust-analyzer/rust-analyzer/issues/3453[2].
+
+|===
+| Editor  | Action Name
+
+| VS Code | **Rust Analyzer: Toggle inlay hints*
+|===
+
+
+=== Join Lines
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/join_lines.rs[join_lines.rs]
+
+Join selected lines into one, smartly fixing up whitespace, trailing commas, and braces.
+
+|===
+| Editor  | Action Name
+
+| VS Code | **Rust Analyzer: Join lines**
+|===
+
+
+=== Magic Completions
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/completion.rs[completion.rs]
+
+In addition to usual reference completion, rust-analyzer provides some ✨magic✨
+completions as well:
+
+Keywords like `if`, `else` `while`, `loop` are completed with braces, and cursor
+is placed at the appropriate position. Even though `if` is easy to type, you
+still want to complete it, to get ` { }` for free! `return` is inserted with a
+space or `;` depending on the return type of the function.
+
+When completing a function call, `()` are automatically inserted. If a function
+takes arguments, the cursor is positioned inside the parenthesis.
+
+There are postfix completions, which can be triggered by typing something like
+`foo().if`. The word after `.` determines postfix completion. Possible variants are:
+
+- `expr.if` -> `if expr {}` or `if let ... {}` for `Option` or `Result`
+- `expr.match` -> `match expr {}`
+- `expr.while` -> `while expr {}` or `while let ... {}` for `Option` or `Result`
+- `expr.ref` -> `&expr`
+- `expr.refm` -> `&mut expr`
+- `expr.not` -> `!expr`
+- `expr.dbg` -> `dbg!(expr)`
+
+There also snippet completions:
+
+.Expressions
+- `pd` -> `println!("{:?}")`
+- `ppd` -> `println!("{:#?}")`
+
+.Items
+- `tfn` -> `#[test] fn f(){}`
+- `tmod` ->
+```rust
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_fn() {}
+}
+```
+
+
+=== Matching Brace
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/matching_brace.rs[matching_brace.rs]
+
+If the cursor is on any brace (`<>(){}[]`) which is a part of a brace-pair,
+moves cursor to the matching brace. It uses the actual parser to determine
+braces, so it won't confuse generics with comparisons.
+
+|===
+| Editor  | Action Name
+
+| VS Code | **Rust Analyzer: Find matching brace**
+|===
+
+
+=== On Typing Assists
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/typing.rs[typing.rs]
+
+Some features trigger on typing certain characters:
+
+- typing `let =` tries to smartly add `;` if `=` is followed by an existing expression
+- Enter inside comments automatically inserts `///`
+- typing `.` in a chain method call auto-indents
+
+
+=== Parent Module
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/parent_module.rs[parent_module.rs]
+
+Navigates to the parent module of the current module.
+
+|===
+| Editor  | Action Name
+
+| VS Code | **Rust Analyzer: Locate parent module**
+|===
+
+
+=== Run
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/runnables.rs[runnables.rs]
+
+Shows a popup suggesting to run a test/benchmark/binary **at the current cursor
+location**. Super useful for repeatedly running just a single test. Do bind this
+to a shortcut!
+
+|===
+| Editor  | Action Name
+
+| VS Code | **Rust Analyzer: Run**
+|===
+
+
+=== Semantic Syntax Highlighting
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/syntax_highlighting.rs[syntax_highlighting.rs]
+
+rust-analyzer highlights the code semantically.
+For example, `bar` in `foo::Bar` might be colored differently depending on whether `Bar` is an enum or a trait.
+rust-analyzer does not specify colors directly, instead it assigns tag (like `struct`) and a set of modifiers (like `declaration`) to each token.
+It's up to the client to map those to specific colors.
+
+The general rule is that a reference to an entity gets colored the same way as the entity itself.
+We also give special modifier for `mut` and `&mut` local variables.
+
+
+=== Show Syntax Tree
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/syntax_tree.rs[syntax_tree.rs]
+
+Shows the parse tree of the current file. It exists mostly for debugging
+rust-analyzer itself.
+
+|===
+| Editor  | Action Name
+
+| VS Code | **Rust Analyzer: Show Syntax Tree**
+|===
+
+
+=== Status
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/status.rs[status.rs]
+
+Shows internal statistic about memory usage of rust-analyzer.
+
+|===
+| Editor  | Action Name
+
+| VS Code | **Rust Analyzer: Status**
+|===
+
+
+=== Structural Seach and Replace
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide/src/ssr.rs[ssr.rs]
+
+Search and replace with named wildcards that will match any expression.
+The syntax for a structural search replace command is `<search_pattern> ==>> <replace_pattern>`.
+A `$<name>:expr` placeholder in the search pattern will match any expression and `$<name>` will reference it in the replacement.
+Available via the command `rust-analyzer.ssr`.
+
+```rust
+// Using structural search replace command [foo($a:expr, $b:expr) ==>> ($a).foo($b)]
+
+// BEFORE
+String::from(foo(y + 5, z))
+
+// AFTER
+String::from((y + 5).foo(z))
+```
+
+|===
+| Editor  | Action Name
+
+| VS Code | **Rust Analyzer: Structural Search Replace**
+|===
+
+
+=== Workspace Symbol
+**Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/ra_ide_db/src/symbol_index.rs[symbol_index.rs]
+
+Uses fuzzy-search to find types, modules and functions by name across your
+project and dependencies. This is **the** most useful feature, which improves code
+navigation tremendously. It mostly works on top of the built-in LSP
+functionality, however `#` and `*` symbols can be used to narrow down the
+search. Specifically,
+
+- `Foo` searches for `Foo` type in the current workspace
+- `foo#` searches for `foo` function in the current workspace
+- `Foo*` searches for `Foo` type among dependencies, including `stdlib`
+- `foo#*` searches for `foo` function among dependencies
+
+That is, `#` switches from "types" to all symbols, `*` switches from the current
+workspace to dependencies.
+
+|===
+| Editor  | Shortcut
+
+| VS Code | kbd:[Ctrl+T]
+|===
diff --git a/docs/user/readme.adoc b/docs/user/readme.adoc
index 64bd0feb133..12def732710 100644
--- a/docs/user/readme.adoc
+++ b/docs/user/readme.adoc
@@ -8,6 +8,8 @@
 :important-caption: :heavy_exclamation_mark:
 :caution-caption: :fire:
 :warning-caption: :warning:
+:source-highlighter: rouge
+:experimental:
 
 // Master copy of this document lives in the https://github.com/rust-analyzer/rust-analyzer repository
 
@@ -268,6 +270,13 @@ Gnome Builder currently has support for RLS, and there's no way to configure the
 1. Rename, symlink or copy the `rust-analyzer` binary to `rls` and place it somewhere Builder can find (in `PATH`, or under `~/.cargo/bin`).
 2. Enable the Rust Builder plugin.
 
-== Usage
+== Features
 
-See https://github.com/rust-analyzer/rust-analyzer/blob/master/docs/user/features.md[features.md].
+include::./generated_features.adoc[]
+
+== Assists (Code Actions)
+
+Assists, or code actions, are small local refactorings, available in a particular context.
+They are usually triggered by a shortcut or by clicking a light bulb icon in the editor.
+
+See [assists.md](./assists.md) for the list of available assists.