feat: infer generic arguments from expected results

TODO.md

@@ -59,7 +59,8 @@ non-FFI allocators and cover zero-sized storage, growth, failure and cleanup.
 existing hash maps execute collision chains, rehashing, duplicate/absent lookups,
 aggregate copies and allocator failure/cleanup through both paths; native checks
 cover automatic integer/bool/enum/distinct/array/record keys, content-based strings
-and custom callbacks with the real C allocator. initializer parameters remain explicit.
+and custom callbacks with the real C allocator. expected result types infer initializer
+types/callbacks, including automatic, string and custom maps.
 `unreachable` is a demanded source trap; terminal literal-true loops need no return.
 `compile_error!` retains owned user messages and skips unselected compile-time bodies.
 boolean and optional-capture `if ... else` expressions reuse checked matches for
@@ -139,8 +140,9 @@ test discovery and FFI remain outside these completed slices.
   - [x] optional conditional-expression checkpoint: `if value |payload| then_value else else_value` reuses canonical presence matches through interpreter/native execution. single-evaluation guards and lazy branches preserve exact immutable by-value captures, nested optional presence, aggregate isolation and runtime pointer/callback/slice/zero-sized payloads. contextual optional/fallible results, constant-input procedures, generated types/defaults and explicit compile-time subject selection retain checked execution and owned payload snapshots. nonoptional guards, capture scope/shadowing, malformed captures, missing `else`, incompatible branches and compile-time overflow retain diagnostics. yielding value blocks are covered below; broader constant materialization remains open.
   - [x] yielding-block checkpoint: value blocks and `yield expression` produce exact/contextual results through interpreter/native execution, including conditional branches, match arms and catch handlers. nested value sources select the nearest target; ordinary blocks/loops preserve it. yielded aggregates snapshot before LIFO cleanup, successful yields skip `errdefer`, and return/error/break/continue retain enclosing targets. ordinary constants, generic branch specialization and type-producing blocks generate owned values, types, storage and defaults. missing operands/results, incompatible yields, capture mutation and outward cleanup transfers retain diagnostics and demand-driven traps; imported provenance and repeatable compilation are verified. labeled yields and value-producing loops remain outside this checkpoint.
   - [x] compound/bitwise checkpoint: arithmetic and bitwise compound updates evaluate mutable local/field/index/pointer places and their old values once before the RHS through interpreter/native execution. integer complement, and/or/xor, truncating left shifts, signed/unsigned right shifts and saturating left shifts preserve widths and distinct identity; unsigned counts retain independent types. known invalid counts diagnose even in untaken runtime branches; dynamic counts trap without native LLVM poison. checked arithmetic, float-only division, readonly diagnostics, scoped cleanup, ordinary constants, generated storage, generic branch selection and repeatable compilation retain existing semantics. type-valued `|` remains composition while runtime `|` and capture delimiters retain their grammar. full hash-map acceptance remains open.
-  - [x] hash-map execution checkpoint: existing `std/hashmap.HashMap`, `AutoHashMap` and `StringHashMap` run collision chains, zero-hash normalization, growth/rehashing, duplicate-key errors, absent lookups and owned aggregate values without replacement library code. interpreter checks use separate typed allocation buffers and preserve the original map on allocation failure, including cleanup; native `mem.c_allocator` checks cover all integer widths/boundaries, booleans, sparse/aliased enums, nested distinct/array/record keys with padding ignored, content-based byte strings and custom callbacks at `-O0`/`-O2`. specialization retains `usize` collection indices, nominal/explicit pointer-cast result types, rigid slice borrowing/string context and source-known optional callbacks; ordinary checking rejects incompatible elements and readonly reversal. `unreachable` demand-traps with provenance through both paths and compile-time execution; literal-true loops distinguish escaping and nested breaks. `compile_error!` owns computed string diagnostics and skips unselected compile-time bodies. initializer inference from expected result types remains open.
-  - [ ] remaining gate: general type-valued compile-time execution, broader constant materialization (including untagged unions and storage-bearing values), expected-result generic inference (including hash-map initializers), plus remaining existing-library acceptance for broader `meta` operations and `io.print`. formatting parsing and broader imported C-binding support may interleave with later gates.
+  - [x] hash-map execution checkpoint: existing `std/hashmap.HashMap`, `AutoHashMap` and `StringHashMap` run collision chains, zero-hash normalization, growth/rehashing, duplicate-key errors, absent lookups and owned aggregate values without replacement library code. interpreter checks use separate typed allocation buffers and preserve the original map on allocation failure, including cleanup; native `mem.c_allocator` checks cover all integer widths/boundaries, booleans, sparse/aliased enums, nested distinct/array/record keys with padding ignored, content-based byte strings and custom callbacks at `-O0`/`-O2`. specialization retains `usize` collection indices, nominal/explicit pointer-cast result types, rigid slice borrowing/string context and source-known optional callbacks; ordinary checking rejects incompatible elements and readonly reversal. `unreachable` demand-traps with provenance through both paths and compile-time execution; literal-true loops distinguish escaping and nested breaks. `compile_error!` owns computed string diagnostics and skips unselected compile-time bodies. initializer inference from expected result types is covered below.
+  - [x] expected-result inference checkpoint: omitted compile-time type/value arguments infer from rigid runtime arguments and expected results before contextual literal defaults. typed bindings, assignments, returns, ordinary/nested calls, aggregate fields/elements/defaults, optional/fallible channels, callbacks, match arms, yielding/catch blocks, arithmetic/bitwise operands and explicit `$()` expressions retain exact checked types through interpreter/native execution. generated nominal results infer counts and private/custom callback identities; existing `hashmap.init(allocator)` initializes `AutoHashMap`, `StringHashMap` and custom `HashMap` without replacement library code. rigid conflicts, unrelated nominal generators and unresolved arguments diagnose; explicit calls and fully explicit type-producer inputs retain their contracts. owned specializations and repeat compilation are verified.
+  - [ ] remaining gate: general type-valued compile-time execution, broader constant materialization (including untagged unions and storage-bearing values), plus remaining existing-library acceptance for broader `meta` operations and `io.print`. formatting parsing and broader imported C-binding support may interleave with later gates.
 - [ ] remaining source constructs: multiline strings. boolean and optional-capture conditional expressions, yielding value blocks, `yield`, compound updates and bitwise operators are covered above. examples: `source/parser/parse.hon`, `source/llvm/runtime.hon`.
 - [ ] standard-library milestone: compile/run a multi-package program exercising existing allocation and IO, including error cleanup; no replacement miniature standard library.
 - [ ] native driver integration: required C ABI declarations, `process.Init` startup arguments/IO, actual CLI exit statuses, file loading, temporary files and spawning Clang. Honey-generated programs currently accept only parameterless `main` and print its result; Bro's bootstrap startup support is not Honey backend support.