#8904 Export nested make values flat, derived from the signature

Every make in a nested module of a file's final signature is also exported as A$B$make, and other modules read it through that name. React Server Components only pass a client module's top-level exports to the client, so <Sidebar.Provider /> no longer reads .make from a client reference. Both sides decide from the signature alone, which replaces @res.hoistedFunction and its .cmj table (#8402); see #8901.

Example ReScript

// Sidebar.resmodule Provider = {  @react.component  let make = (~children) => children}// Page.reslet page = <Sidebar.Provider> {React.null} </Sidebar.Provider>

// Page.res.jsJsxRuntime.jsx(Sidebar.Provider.make, {children: null})

// Sidebar.res.jslet Provider$make = Sidebar$Provider;export { Provider, Provider$make }// Page.res.jsJsxRuntime.jsx(Sidebar.Provider$make, {children: null})

Source After from tests/build_tests/react_ppx/src/nested_component_*.res.js in this diff. Before is master's fallback for a nested read without a .cmj hoisting entry.

Review

• Why can't a .resi edit leave consumers stale, as in #8886? The flat export set is a function of the signature, so it changes exactly when the .cmi does, and both build systems already rebuild dependents then. Changing only Sidebar.res behind an unchanged .resi (a module alias, an external, a functor application, include) kept the .cmi byte-identical and every flat export in a scratch build.
• Do the aliases defeat tree-shaking? When the module field holds a top-level binding, the alias is let A$B$make = make. Only fields without one (a wrapped value such as Some(make), a functor result, an awaited module) fall back to a property read.
• What about name clashes? A flat name already used by a top-level binding is a compile error, as it was for @res.hoistedFunction.

No effect

Formatting: unchangedPPX: unchangedEditor: unchanged

Output

changedprograms with nested make values gain flat exports and read them from other modules; 26 committed outputs change, all additive apart from the rewritten reads, and 3 go with the removed tests

Formats

cmi

Errors

none, because the new clash error is an inline raise_errorf, outside the catalog's scope

Tests

build tests/build_tests/+ react_ppx/src/nested_component_producer.res+ react_ppx/src/nested_component_consumer.res

super_errors tests/build_tests/+ super_errors/fixtures/flat_make_export_collision.res~ super_errors/fixtures/warning_101_bs_unused_attribute.res− super_errors/fixtures/hoisted_function_*.res

integration tests/tests/src/~ flat_make_export*.res (from hoisted_function_attr*.res)~ import2.res

• Changelog fragment changes/flat-make-exports.feature.md
• Changelog fragment changes/remove-hoisted-function.breaking.md
• 29 committed generated JS files change; 4 new
• Magic numbers bumped: cmi Caml1999I039
• 1 new super_errors fixture; ERROR_VARIANTS.md unchanged, as the Errors trailer states