feat: expand constant inline for loops

README.md

@@ -102,7 +102,9 @@ type-producing bodies support mutable type and value locals, direct binding assi
 
 field/index assignments also update initialized, materializable aggregate locals in type-producing bodies, including nested record fields and mutable fixed-array elements. for example, `counts [2]mut usize := [0, 0]` followed by `counts[1] = 2` can generate `[counts[1]]i16` storage. array snapshots preserve earlier copies; scalar and ordinary record-field operations reuse checked IR. later loop iterations, generated lengths and defaults observe updates. ordinary mutability, index-type/bounds, field and exact value-type checks still apply, including immutable payload captures and narrow arithmetic overflow. imported producers and repeated compilation retain source diagnostics and nominal cache identity; pointer/slice-backed mutation remains open.
 
-type-producing bodies also iterate materializable fixed arrays and strings with immutable by-value element captures and optional `usize` indices: `for counts |count, index| { length = length + count + index }` can compute generated storage. nested loops, aggregate captures, empty collections, break/continue and early returns share the type-control execution bound. array places retain their entry-time indices and observe later element updates; temporary arrays and strings are evaluated once. ordinary constant-input procedures additionally support slice and pointer captures through checked IR, provided only materializable results escape. type-producing loop bodies still reject storage-bearing captures rather than retaining temporary interpreter addresses; `inline for` remains open.
+type-producing bodies also iterate materializable fixed arrays and strings with immutable by-value element captures and optional `usize` indices: `for counts |count, index| { length = length + count + index }` can compute generated storage. nested loops, aggregate captures, empty collections, break/continue and early returns share the type-control execution bound. array places retain their entry-time indices and observe later element updates; temporary arrays and strings are evaluated once. ordinary constant-input procedures additionally support slice and pointer captures through checked IR, provided only materializable results escape. type-producing loop bodies still reject storage-bearing captures rather than retaining temporary interpreter addresses.
+
+`inline for` expands constant integer ranges, fixed arrays (including arrays of `type`) and strings into separately checked runtime bodies. captures are immutable exact-type constants; collection indices are `usize`. for example, `inline for [i16, bool] |T| { if (T == i16) { value T :: 42 } else { value T :: true } }` checks only each iteration's selected branch. bounds/iterables are computed before expansion, empty loops skip body elaboration, and nested expansions share the 4096-step type-control bound. `break` and `continue` targeting the inline loop must be selected entirely at compile time; selected exits prune the remaining body and `break` skips subsequent iterations. nested ordinary loops retain runtime transfers, while runtime returns, errors and scoped cleanup retain ordinary semantics. runtime-dependent inputs, pointer captures and storage-bearing values that cannot escape constant evaluation are diagnosed. heterogeneous tuple iteration, metadata collections and inline-match syntax remain open.
 
 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.