LSP Support

The Mist Language Server Protocol implementation runs a headless rust-analyzer instance and bridges Mist editor requests to Rust positions.

Architecture

Editor (LSP client)
    │
    ▼
┌─────────────────────┐
│   mist-analyzer     │
│   (Rust + Mist)     │
└─────────────────────┘
    │           ▲
    │  JSON-RPC │
    ▼           │
┌─────────────────────┐
│   rust-analyzer     │
│   (headless child)  │
└─────────────────────┘

Flow

1. Editor sends Mist file edits to mist-analyzer via LSP
2. mist-analyzer transpiles Mist to Rust
3. The transpiled Rust is forwarded to the headless rust-analyzer process
4. For goto-definition, hover, and completion, a unique marker token is injected at the cursor position
5. The transpiled output with the marker is sent to rust-analyzer
6. The marker position is located in the response
7. Results are mapped back to Mist positions using the rev_mapper

Key Features

• Full document sync — Open, change, save, close
• Go to definition — Maps through transpiled Rust positions
• Completions — Supports trigger characters :, ., ', (
• Hover — Type information and docs
• Diagnostics — Real-time errors from transpilation failures and Rust compilation
• Formatting — Document formatting support
• Auto-import — Automatically inserts pub module <name>; when new .mist files are created
• File watching — Monitors **/*.mist for new files

Diagnostic Remapping

When a transpilation error occurs in the mist-analyzer:

1. Parse errors are converted to Diagnostic with Mist source positions
2. Semantic errors (uninitialized class fields) use the stored line/column
3. Rust compiler errors are remapped via the Mapping system back to Mist positions