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46c02aee61
Add scope flags to `TraverseCtx`. Closes #3189. `walk_*` functions build a stack of `ScopeFlags` as AST is traversed, and they can be queried from within visitors with `ctx.scope()`, `ctx.ancestor_scope()` and `ctx.find_scope()`. The codegen which generates `walk_*` functions gets the info about which AST types have scopes, and how to check for strict mode from the `#[visited_node]` attrs on AST type definitions in `oxc_ast`. A few notes: Each scope inherits the strict mode flag from the level before it in the stack, so if you need to know "am I in strict mode context here?", `ctx.scope().is_strict_mode()` will tell you - no need to travel back up the stack to find out. Scopes do *not* inherit any other flags from level before it. So `ctx.scope()` in a block nested in a function will return `ScopeFlags::empty()` not `ScopeFlags::Function`. I had to add an extra flag `ScopeFlags::Method`. The reason for this is to deal with when a `Function` is actually a `MethodDefinition`, and to avoid creating 2 scopes in this case. The principle I'm trying to follow is to encode as little logic in the codegen as possible, as it's rather hidden away. Instead the codegen follows a standard logic for every node, guided by attributes which are visible next to the types in `oxc_ast`. This hopefully makes how `Traverse`'s visitors are generated less mysterious, and easier to change. The case of `Function` within `MethodDefinition` is a weird one and would not be possible to implement without encoding a magic "special case" within the codegen without this extra `ScopeFlags::Method` variant. Its existence does not alter the operation of any other code in Oxc which uses `ScopeFlags`. In my view `ScopeFlags` might benefit from a little bit of an overhaul anyway. I believe we could pack more information into the bits and make it more useful. |
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| .. | ||
| oxc | ||
| oxc_allocator | ||
| oxc_ast | ||
| oxc_ast_macros | ||
| oxc_cli | ||
| oxc_codegen | ||
| oxc_diagnostics | ||
| oxc_index | ||
| oxc_js_regex | ||
| oxc_language_server | ||
| oxc_linter | ||
| oxc_macros | ||
| oxc_minifier | ||
| oxc_module_lexer | ||
| oxc_parser | ||
| oxc_prettier | ||
| oxc_semantic | ||
| oxc_sourcemap | ||
| oxc_span | ||
| oxc_syntax | ||
| oxc_transformer | ||
| oxc_traverse | ||
| oxc_wasm | ||