feat: construct partial compile-time type records

README.md

@@ -112,11 +112,13 @@ inline tuples may mix types and values, including nested aggregates, strings, op
 
 initialized fixed arrays of `type` live entirely inside compile-time execution, including nested arrays, explicit/inferred annotations, `.len`, checked `usize` indexing and collection captures. for example, `types [2]mut type := [i8, bool]`, then `types[1] = i16` and `return [types.len]types[1]`, generates `[2]i16` without runtime type metadata. whole-array and nested indexed assignments preserve shape and mutability at every level; copies and loop captures retain earlier values while borrowed array places observe later updates.
 
-initialized records/tuples containing `type` fields live inside compile-time producers. local schemas, typed/contextual/anonymous construction, defaults, nested records/arrays, field/index reads and updates, whole-value replacement and by-value collection captures retain owned snapshots. for example, `config struct { child type, count usize } := { child = i8, count = 2 }`, then `config.child = i16` and `return [config.count]config.child`, generates `[2]i16`. earlier copies and loop captures remain independent, while borrowed array places observe later updates. type leaves retain nominal identity; ordinary value leaves reuse checked constant execution. unknown/duplicate/missing fields, invalid types/defaults, readonly places, narrow overflow and dependency provenance retain diagnostics. record validation/construction shares the type-control bound. runtime type-valued records, partial record initialization, metadata reflection and inline expansion remain open.
+initialized records/tuples containing `type` fields live inside compile-time producers. local schemas, typed/contextual/anonymous construction, defaults, nested records/arrays, field/index reads and updates, whole-value replacement and by-value collection captures retain owned snapshots. for example, `config struct { child type, count usize } := { child = i8, count = 2 }`, then `config.child = i16` and `return [config.count]config.child`, generates `[2]i16`. earlier copies and loop captures remain independent, while borrowed array places observe later updates. type leaves retain nominal identity; ordinary value leaves reuse checked constant execution. unknown/duplicate/missing fields, invalid types/defaults, readonly places, narrow overflow and dependency provenance retain diagnostics. record validation/construction shares the type-control bound. runtime type-valued records remain unsupported.
+
+type-valued records/tuples may also start with `undefined`: `config struct { child type, count usize } := undefined`, then `config.child = i16` and `config.count = 2`. nested record fields, arrays of records, tuple ordinals and `field!` updates use the same persistent snapshots as initialized storage; partial copies retain independent initialization state. defaults do not initialize `undefined` fields. initialized leaves and array lengths can be read while other leaves remain uninitialized, but premature leaf reads and incomplete procedure arguments/results diagnose read-before-initialization. fully initialized results cross compile-time procedure boundaries and supply erased generic inputs, generated storage and defaults. empty shapes are initialized vacuously; each expanded record field/array cell shares the construction bound.
 
 fixed type arrays may also start with `undefined` inside type/type-array producers: `types [2]mut type := undefined`, then fill `types[index] = i16` in a loop. nested and whole-array updates preserve shape, mutability and independent initialization state in local copies; `.len` is available before elements initialize. reading an uninitialized type leaf, returning an incomplete array or passing one to a compile-time procedure diagnoses a read before initialization. empty shapes are valid, but every dimension must be explicit and nonnegative. construction charges each expanded cell against the shared execution bound, including nested zero-leaf shapes.
 
-ordinary fixed value arrays use the same construction inside type/type-array producers: `counts [2]mut usize := undefined`, then fill indexed elements or replace whole rows/arrays. initialized leaves retain exact scalar, string, optional, record and tagged-union values; local copies retain independent partial initialization state. generated lengths/defaults and compile-time arguments can use initialized elements, while incomplete arrays cannot enter checked IR or procedure arguments. array `.len` and empty shapes do not read leaves. partial type-valued record construction and constant materialization of mutable slices or nonnull data pointers remain unsupported.
+ordinary fixed value arrays use the same construction inside type/type-array producers: `counts [2]mut usize := undefined`, then fill indexed elements or replace whole rows/arrays. initialized leaves retain exact scalar, string, optional, record and tagged-union values; local copies retain independent partial initialization state. generated lengths/defaults and compile-time arguments can use initialized elements, while incomplete arrays cannot enter checked IR or procedure arguments. array `.len` and empty shapes do not read leaves. constant materialization of mutable slices or nonnull data pointers remains unsupported.
 
 ordinary procedures also accept `undefined` as the initializer of a mutable local with a concrete runtime type, including nested records and fixed arrays. field/index writes initialize storage without reading its previous contents; aggregate copies retain independent contents and initialization state in the interpreter. ordinary compile-time calls can fill this storage and return materializable values, but observing or materializing an uninitialized leaf is diagnosed. native storage uses LLVM poison, not zero initialization: assign every leaf before observing it, and do not rely on native read-before-initialization traps for `undefined` storage. immutable bindings, globals, inferred array lengths and other expression uses remain invalid.