Rust Analyzer Workflows

Rust Analyzer Workflows

Overview

Use rust-analyzer as the default first tool for Rust codebase exploration and refactors. If a standalone rust-analyzer is missing, first try to install it for the active toolchain, then fall back to rg only when installation is not possible, fails, or the task is explicitly about exact text literals, paths, comments, or non-Rust files.

This skill was cross-checked against the official rust-analyzer book, especially:

• book/contributing/lsp-extensions.html
• book/features.html
• book/configuration
• book/diagnostics.html
• book/troubleshooting.html

Prefer the lightest workflow that answers the question:

• Syntax only: use parse
• Workspace diagnostics: use diagnostics
• Single-file structure or semantic coloring: use symbols / highlight
• Structured search/replace: use search / ssr
• Cache warming, index export, or workspace-scale stats: use prime-caches, scip, lsif, or analysis-stats --skip-inference
• IDE-like navigation, editor actions, and rust-analyzer debug requests: use direct LSP requests or the bundled script

Default bias:

• Start with a rust-analyzer workflow first
• If standalone rust-analyzer is missing, try to install it before changing tools
• Drop to rg only when you need literal-text grep semantics or a fallback around a rust-analyzer failure mode

Quick Start

Use these CLI commands first:

rust-analyzer --version
rust-analyzer parse --no-dump < path/to/file.rs
rust-analyzer diagnostics . --disable-build-scripts --disable-proc-macros --severity error
rust-analyzer symbols < path/to/file.rs
rust-analyzer highlight < path/to/file.rs
rust-analyzer prime-caches . --disable-build-scripts --disable-proc-macros
rust-analyzer analysis-stats . --disable-build-scripts --disable-proc-macros --skip-inference
rust-analyzer scip . --output /tmp/project.scip
rust-analyzer lsif . > /tmp/project.lsif
rust-analyzer --print-config-schema
rust-analyzer search '$a.foo($b)'
rust-analyzer ssr '$a.foo($b) ==>> bar($a, $b)'

For LSP-style requests, use {baseDir}/scripts/rust_analyzer_lsp.py.

Workflow

1. Confirm tool availability

Run:

command -v rust-analyzer
rust-analyzer --version
rust-analyzer --help
rustup which rust-analyzer

Do this before relying on CLI subcommands or LSP behavior.

If the shell command is missing or rustup reports an unknown rust-analyzer binary, do not immediately give up on semantic tooling. Prefer this order:

1. verify whether a standalone toolchain binary already exists via rustup which rust-analyzer
2. if it is genuinely missing, try to install it for the active toolchain with rustup component add rust-analyzer --toolchain <active-toolchain>
3. only after install is impossible or fails, fall back to rg, source reading, or other non-VS-Code tools

If VS Code is involved, distinguish three different things:

• the shell-visible executable from command -v rust-analyzer
• the current toolchain binary from rustup which rust-analyzer
• the VS Code extension bundled server under ~/.vscode/extensions/rust-lang.rust-analyzer-*/server/rust-analyzer or ~/.vscode-server/extensions/rust-lang.rust-analyzer-*/server/rust-analyzer

If you want VS Code to use the toolchain or a custom binary instead of the bundled server, set rust-analyzer.server.path to an explicit executable path, usually the output of command -v rust-analyzer or rustup which rust-analyzer.

For version discovery:

• Command line: run rust-analyzer --version
• VS Code command palette: official docs point to rust-analyzer: Show RA Version
• In VS Code, Ctrl+Shift+P is the documented way to open the command palette
• If you prefer Ctrl+P, type >rust-analyzer: Show RA Version

2. Use CLI before raw LSP when possible

Prefer:

• parse --no-dump for syntax checks on a specific file
• diagnostics for workspace-level semantic errors
• symbols for a fast outline of one file
• highlight for semantic token / highlighting inspection
• prime-caches when semantic requests are timing out or returning early empty results on a cold workspace
• analysis-stats --skip-inference for workspace shape, item-tree volume, and low-risk batch analysis
• scip / lsif when you need an exported semantic index rather than an editor-style answer
• --print-config-schema for the authoritative list of rust-analyzer.* settings
• search for structured AST matching
• ssr for structured replacement

Read references/cli-and-lsp.md when you need command templates or current behavior notes.

3. Use direct LSP for IDE-like navigation

Use raw LSP or the bundled script when you need:

• definition
• references
• typeDefinition
• implementation
• workspaceSymbol
• workspaceSymbol with scope / kind filtering
• documentSymbol
• documentHighlight
• selectionRange
• foldingRange
• hover
• completion
• signatureHelp
• inlayHint
• semanticTokensFull
• prepareRename
• rename
• codeAction
• formatting
• prepareCallHierarchy
• incomingCalls
• outgoingCalls
• analyzerStatus
• expandMacro
• externalDocs
• parentModule
• runnables
• relatedTests
• viewSyntaxTree
• viewHir
• viewMir
• viewItemTree
• viewFileText
• getFailedObligations
• interpretFunction
• openCargoToml
• viewRecursiveMemoryLayout
• reloadWorkspace

For text-document methods, always send didOpen before the request. In practice this avoided file not found results during local testing. Also allow a short warm-up window before semantic requests. During local testing, semantic requests became stable after a few seconds of indexing plus retry on transient empty or content modified responses.

Use:

python3 {baseDir}/scripts/rust_analyzer_lsp.py \
  --workspace /path/to/repo \
  --file src/lib.rs \
  --line 10 \
  --character 5 \
  --method definition

Useful extra examples:

python3 {baseDir}/scripts/rust_analyzer_lsp.py \
  --workspace /path/to/repo \
  --method workspaceSymbol \
  --query SupervisedTaskHandle

python3 {baseDir}/scripts/rust_analyzer_lsp.py \
  --workspace /path/to/repo \
  --file src/lib.rs \
  --line 20 \
  --character 12 \
  --method codeAction \
  --only refactor

python3 {baseDir}/scripts/rust_analyzer_lsp.py \
  --workspace /path/to/repo \
  --file src/lib.rs \
  --line 42 \
  --character 9 \
  --method incomingCalls

python3 {baseDir}/scripts/rust_analyzer_lsp.py \
  --workspace /path/to/repo \
  --file src/lib.rs \
  --line 26 \
  --character 7 \
  --method expandMacro

python3 {baseDir}/scripts/rust_analyzer_lsp.py \
  --workspace /path/to/repo \
  --file src/lib.rs \
  --line 1 \
  --character 15 \
  --method externalDocs

python3 {baseDir}/scripts/rust_analyzer_lsp.py \
  --workspace /path/to/repo \
  --file src/lib.rs \
  --line 34 \
  --character 7 \
  --method runnables

python3 {baseDir}/scripts/rust_analyzer_lsp.py \
  --workspace /path/to/repo \
  --method workspaceSymbol \
  --query Supervised \
  --symbol-scope workspace \
  --symbol-kind onlyTypes

python3 {baseDir}/scripts/rust_analyzer_lsp.py \
  --workspace /path/to/repo \
  --file src/lib.rs \
  --line 31 \
  --character 8 \
  --method viewHir

python3 {baseDir}/scripts/rust_analyzer_lsp.py \
  --workspace /path/to/repo \
  --file src/lib.rs \
  --line 43 \
  --character 31 \
  --method viewRecursiveMemoryLayout

Useful VS Code / binary discovery commands:

command -v rust-analyzer
rust-analyzer --version
rustup which rust-analyzer
setopt null_glob; print -l ~/.vscode/extensions/rust-lang.rust-analyzer-* ~/.vscode-server/extensions/rust-lang.rust-analyzer-*
setopt null_glob; print -l ~/.vscode/extensions/rust-lang.rust-analyzer-*/server/rust-analyzer ~/.vscode-server/extensions/rust-lang.rust-analyzer-*/server/rust-analyzer

4. Know the capability-gated features

• Richer codeAction results depend on the client advertising code-action literal support.
• Auto-import flavored completion results are better when the client advertises completion resolve support for additionalTextEdits.
• The bundled script now declares those capabilities and can optionally run completionItem/resolve with --resolve-index.
• externalDocs can return both web and local docs URLs when the client advertises localDocs.
• Enabling diagnostic pull support means rust-analyzer may send back client-directed refresh requests such as workspace/diagnostic/refresh; the bundled script now acknowledges those requests instead of mistaking them for normal responses.
• formatting is easy to drive over raw LSP, but rangeFormatting is still separate and depends on rust-analyzer.rustfmt.rangeFormatting.enable.

5. Treat unresolved-references as opportunistic

rust-analyzer unresolved-references is useful in theory for post-refactor scans, but it is not as stable as diagnostics.

If it panics or crashes:

• fall back to targeted rg
• run diagnostics
• use direct definition / references queries for the suspicious symbols

Do not block the task on unresolved-references.

analysis-stats also needs a caution:

• In the current validated environment, analysis-stats --skip-inference works.
• Full analysis-stats with inference enabled can still hit the same attached db panic class as unresolved-references.
• Prefer --skip-inference unless you are deliberately probing rust-analyzer internals.

Decision Rules

• Use rust-analyzer first for Rust discovery, navigation, and refactor planning.
• Use workspaceSymbol, symbols, documentSymbol, definition, references, search, or direct LSP before broad manual file-walking.
• If standalone rust-analyzer is missing, try to install it for the active toolchain before switching to text-only tooling.
• Use rg only when the task is primarily about exact text matching, path discovery, comments/strings, non-Rust assets, or when rust-analyzer has already proven unreliable for the specific query and installation/repair is not the right next step.
• Use diagnostics instead of cargo check when the user has asked to avoid compilation-heavy validation.
• Use symbols and workspaceSymbol before wide manual file-walking when you need a semantic outline.
• Use ssr before hand-editing repetitive Rust refactors.
• Use codeAction for local assists and quick fixes before hand-editing syntax-only rewrites.
• Use call hierarchy workflows before large rename / ownership refactors that may ripple across modules.
• Use expandMacro before guessing what a macro-generated item looks like.
• Use runnables and relatedTests when you need rust-analyzer's own understanding of what can be run or which tests cover a symbol.
• Use analyzerStatus, viewSyntaxTree, viewHir, viewMir, viewItemTree, viewFileText, or getFailedObligations when ordinary navigation works but the server's internal semantic view is suspicious.
• Use interpretFunction for tiny pure helper functions when you want a quick semantic sanity check without compiling the workspace.
• Use viewRecursiveMemoryLayout when layout, padding, or field ordering matters for performance work.
• Use openCargoToml when you need fast crate-root navigation from a source file.
• Use rust-analyzer.server.path when you need VS Code to use a known toolchain or custom server binary rather than the extension-bundled executable.
• Use direct LSP when the user explicitly wants IDE-like behavior.

Practical Refactor Heuristics

For repository refactors, rust-analyzer should be the default discovery layer. Treat rg as a supporting raw-text tool, not the primary entry point.

Use it when the expensive part of the task is understanding the code rather than rewriting the filesystem:

• enumerate which struct, enum, trait, and impl blocks actually exist in a file
• confirm which callers, exports, or re-exports depend on a symbol before moving it
• perform safer symbol renames or inspect available code actions
• run lightweight semantic diagnostics after a refactor pass

Do not expect it to fully replace manual file-layout work:

• creating many new files
• rewriting mod.rs, pub use, or #[path = "..."] wiring
• physically splitting structs.rs / struct_impl.rs into per-type files
• enforcing repository-specific naming and owner conventions

For tasks like splitting structs.rs / struct_impl.rs, the fastest pattern is usually hybrid:

1. use workspaceSymbol, symbols, or documentSymbol to find candidate files, types, and impl blocks
2. use definition, references, workspaceSymbol, rename, or codeAction to check the semantic blast radius
3. use rg only as a supporting pass for exact literals, module wiring strings, macro callsites, or non-Rust files that rust-analyzer will not model well
4. use file edits to create the new owner files and rewire the module facade
5. validate with diagnostics, then cargo check / cargo test --no-run when needed

Heuristic:

• if the hard part is “what owns this symbol?” or “who depends on this method?”, start with rust-analyzer
• if the hard part is “how should these files be reorganized?”, use rust-analyzer first to understand ownership, then patch files manually
• if the hard part is “where does this exact literal/path/comment appear?”, use rg as a narrow supporting tool
• for large structural cleanups, the hybrid workflow is usually faster and safer than either pure rust-analyzer or pure text search alone

Resources

{baseDir}/scripts/rust_analyzer_lsp.py

Run a single rust-analyzer LSP request against a workspace and print the JSON result.

Supported methods:

• definition
• references
• diagnostic
• typeDefinition
• implementation
• workspaceSymbol
• documentSymbol
• documentHighlight
• selectionRange
• foldingRange
• hover
• completion
• signatureHelp
• inlayHint
• semanticTokensFull
• prepareRename
• rename
• codeAction
• formatting
• prepareCallHierarchy
• incomingCalls
• outgoingCalls
• analyzerStatus
• expandMacro
• externalDocs
• getFailedObligations
• interpretFunction
• openCargoToml
• parentModule
• runnables
• relatedTests
• viewSyntaxTree
• viewHir
• viewItemTree
• viewMir
• viewFileText
• viewRecursiveMemoryLayout
• fetchDependencyList
• viewCrateGraph
• rebuildProcMacros
• reloadWorkspace

The script already applies a conservative default:

• wait 3000ms after didOpen
• retry transient empty or content modified semantic responses
• acknowledge server-initiated requests such as workspace/diagnostic/refresh

For rename, pass --new-name <identifier>. The script only returns the WorkspaceEdit result and does not automatically write the rename to disk. For workspaceSymbol, --file is optional and can be omitted. For workspaceSymbol, you can further narrow the results with --symbol-scope workspace|workspaceAndDependencies and --symbol-kind onlyTypes|allSymbols. For completion, you can pass --resolve-index <n> to also run completionItem/resolve. For codeAction, pass one or more --only ... filters such as refactor or quickfix. For incomingCalls / outgoingCalls, the script first runs prepareCallHierarchy at the given position and then issues the corresponding hierarchy request. For viewCrateGraph, pass --full-graph to include dependency and sysroot crates. diagnostic, fetchDependencyList, and viewCrateGraph are currently exposed for experiments, but they are not promoted as default workflows until they produce consistently useful results in the current environment. viewHir, viewMir, getFailedObligations, interpretFunction, openCargoToml, viewRecursiveMemoryLayout, and rebuildProcMacros were validated locally after checking the official LSP extension docs.

references/cli-and-lsp.md

Read this when you need:

• current command recommendations
• known limitations
• an explanation of why didOpen matters
• VS Code binary-selection guidance
• a summary of the observed behavior from the repository discussion that motivated this skill

Source: developerworks/rust-supervisor — distributed by TomeVault.