hemx/work/slices/SLICE-0005-lsp-diagnostics-parity.md

id, type, status, parent, title, refs

id	type	status	parent	title	refs
SLICE-0005	slice	ready	NS-0002	Prove LSP diagnostics parity with hemx-build	REQUIREMENTS.md docs/diagnostics.md docs/editor-support.md hemx-lsp/src/main.rs hemx-build/src/lib.rs

Objective

Make LSP diagnostics a faithful editor transport for hemx-build diagnostics across open, change, save, close, and CLI file checks.

Authority

docs/diagnostics.md and REQUIREMENTS.md diagnostics/004, diagnostics/005, and check/001 require editor overlays to share compiler authority and preserve useful spans.

Close when

• A focused LSP test opens an invalid .heml document and observes the same diagnostic code/severity/range as the hemx-lsp diagnostics FILE.heml path.
• didChange updates diagnostics from in-memory text.
• didSave with and without text uses the documented source of truth.
• didClose clears diagnostics.

Verification

• cargo test -p hemx-lsp
• cargo run -p hemx-lsp -- diagnostics <fixture>.heml
• cargo check --workspace if public LSP/build types change.

Non-goals

• Do not implement a second .heml parser in the LSP.
• Do not add provider-specific VS Code/Neovim behavior in this slice.

Evidence

hemx-lsp/src/main.rs already has diagnostics CLI and LSP publish paths that can be covered with protocol tests.