199 lines
6.5 KiB
Markdown
199 lines
6.5 KiB
Markdown
This document is an index of features that the rust-analyzer language server
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provides. Shortcuts are for the default VS Code layout. If there's no shortcut,
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you can use <kbd>Ctrl+Shift+P</kbd> to search for the corresponding action.
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### Workspace Symbol <kbd>ctrl+t</kbd>
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Uses fuzzy-search to find types, modules and functions by name across your
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project and dependencies. This is **the** most useful feature, which improves code
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navigation tremendously. It mostly works on top of the built-in LSP
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functionality, however `#` and `*` symbols can be used to narrow down the
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search. Specifically,
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- `Foo` searches for `Foo` type in the current workspace
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- `foo#` searches for `foo` function in the current workspace
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- `Foo*` searches for `Foo` type among dependencies, including `stdlib`
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- `foo#*` searches for `foo` function among dependencies
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That is, `#` switches from "types" to all symbols, `*` switches from the current
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workspace to dependencies.
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### Document Symbol <kbd>ctrl+shift+o</kbd>
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Provides a tree of the symbols defined in the file. Can be used to
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* fuzzy search symbol in a file (super useful)
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* draw breadcrumbs to describe the context around the cursor
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* draw outline of the file
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### On Typing Assists
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Some features trigger on typing certain characters:
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- typing `let =` tries to smartly add `;` if `=` is followed by an existing expression
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- Enter inside comments automatically inserts `///`
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- typing `.` in a chain method call auto-indents
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### Extend Selection
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Extends the current selection to the encompassing syntactic construct
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(expression, statement, item, module, etc). It works with multiple cursors. This
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is a relatively new feature of LSP:
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https://github.com/Microsoft/language-server-protocol/issues/613, check your
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editor's LSP library to see if this feature is supported.
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### Go to Definition
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Navigates to the definition of an identifier.
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### Go to Implementation
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Navigates to the impl block of structs, enums or traits. Also implemented as a code lens.
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### Go to Type Defintion
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Navigates to the type of an identifier.
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### Commands <kbd>ctrl+shift+p</kbd>
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#### Run
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Shows a popup suggesting to run a test/benchmark/binary **at the current cursor
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location**. Super useful for repeatedly running just a single test. Do bind this
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to a shortcut!
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#### Parent Module
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Navigates to the parent module of the current module.
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#### Matching Brace
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If the cursor is on any brace (`<>(){}[]`) which is a part of a brace-pair,
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moves cursor to the matching brace. It uses the actual parser to determine
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braces, so it won't confuse generics with comparisons.
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#### Join Lines
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Join selected lines into one, smartly fixing up whitespace and trailing commas.
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#### Show Syntax Tree
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Shows the parse tree of the current file. It exists mostly for debugging
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rust-analyzer itself.
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#### Expand Macro Recursively
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Shows the full macro expansion of the macro at current cursor.
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#### Status
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Shows internal statistic about memory usage of rust-analyzer.
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#### Show RA Version
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Show current rust-analyzer version.
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#### Run Garbage Collection
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Manually triggers GC.
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#### Start Cargo Watch
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Start `cargo watch` for live error highlighting. Will prompt to install if it's not already installed.
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#### Stop Cargo Watch
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Stop `cargo watch`.
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#### Structural Seach and Replace
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Search and replace with named wildcards that will match any expression.
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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`.
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```rust
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// Using structural search replace command [foo($a:expr, $b:expr) ==>> ($a).foo($b)]
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// BEFORE
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String::from(foo(y + 5, z))
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// AFTER
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String::from((y + 5).foo(z))
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```
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### Assists (Code Actions)
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Assists, or code actions, are small local refactorings, available in a particular context.
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They are usually triggered by a shortcut or by clicking a light bulb icon in the editor.
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See [assists.md](./assists.md) for the list of available assists.
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### Magic Completions
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In addition to usual reference completion, rust-analyzer provides some ✨magic✨
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completions as well:
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Keywords like `if`, `else` `while`, `loop` are completed with braces, and cursor
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is placed at the appropriate position. Even though `if` is easy to type, you
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still want to complete it, to get ` { }` for free! `return` is inserted with a
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space or `;` depending on the return type of the function.
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When completing a function call, `()` are automatically inserted. If a function
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takes arguments, the cursor is positioned inside the parenthesis.
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There are postifx completions, which can be triggerd by typing something like
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`foo().if`. The word after `.` determines postifx completion. Possible variants are:
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- `expr.if` -> `if expr {}`
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- `expr.match` -> `match expr {}`
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- `expr.while` -> `while expr {}`
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- `expr.ref` -> `&expr`
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- `expr.refm` -> `&mut expr`
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- `expr.not` -> `!expr`
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- `expr.dbg` -> `dbg!(expr)`
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There also snippet completions:
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#### Inside Expressions
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- `pd` -> `println!("{:?}")`
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- `ppd` -> `println!("{:#?}")`
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#### Inside Modules
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- `tfn` -> `#[test] fn f(){}`
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### Code Highlighting
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Experimental feature to let rust-analyzer highlight Rust code instead of using the
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default highlighter.
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#### Rainbow Highlighting
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Experimental feature that, given code highlighting using rust-analyzer is
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active, will pick unique colors for identifiers.
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### Code hints
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Rust-analyzer has two types of hints to show the information about the code:
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* hover hints, appearing on hover on any element.
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These contain extended information on the hovered language item.
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* inlay hints, shown near the element hinted directly in the editor.
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Two types of inlay hints are displayed currently:
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* type hints, displaying the minimal information on the type of the expression (if the information is available)
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* parameter name hints, displaying the names of the parameters in the corresponding methods
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#### VS Code
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In VS Code, the following settings can be used to configure the inlay hints:
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* `rust-analyzer.displayInlayHints` — toggles inlay hints display on or off
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* `rust-analyzer.maxInlayHintLength` — shortens the hints if their length exceeds the value specified. If no value is specified (`null`), no shortening is applied.
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**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.
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This approach has limitations: the caret movement near the end of the hint may look [weird](https://github.com/rust-analyzer/rust-analyzer/issues/1623).
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