forst-lang / forst / 24696999903

76%

main: 76%

Pull #94

github

feat(transform): errMissingMapKey sentinel and map-read FuncLit cache

Emit `var errMissingMapKey = errors.New("missing map key")` once via
`TransformerOutput.EnsureErrMissingMapKeyDecl`, reuse in map-read IIFEs, and
cache identical `*ast.FuncLit` per function (`mapIndexExprCacheKey`, hit counter
for tests). `goZeroValueGoAST` returns `nil` for pointers; add table tests and
golden/pipeline/compiler marker updates.

feat(lsp): hover on `[` after a map variable

When the cursor is on `LBracket` following a map-typed identifier, show that
lookup is `Result(V, Error)` and to use `ensure … is Ok()` before using `V`.

fix(typechecker): targeted `string()` error for raw map index Result

If the operand is a map subscript typed as `Result`, diagnose map lookup
explicitly instead of only "unsupported operand type Result". Add
`inferExpressionTypeWithExpected` hook for `IndexExpressionNode` and nested /
chained map tests.

docs(ts): clarify Result lowering vs generated TS union

Comment on `TypeResult` in `GeeScriptType`: TS discriminated union is a
static signature hint; Go remains `(T, error)` unless a codec maps wire data.

Example (diagnostic):

```forst
println(string(m["a"])) // map lookup has type Result(V, Error); use ensure first
```

204 of 262 new or added lines in 11 files covered. (77.86%)

21338 of 27969 relevant lines covered (76.29%)

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