feat: execute existing hash maps through Honey

README.md

@@ -136,6 +136,8 @@ ordinary procedures may compute integer, boolean, float and string compile-time
 
 `if $(condition) { ... } else { ... }` evaluates a boolean guard before expanding or checking either body, including calls to ordinary constant-input procedures. concrete generic specializations also select branches whose guards use constants, immutable constant bindings, type comparisons or substituted compile-time parameters. only the selected body is specialized and checked; both bodies are still parsed and name-resolved. selected bodies retain their scope, cleanup and return behavior, and erased guards retain ordinary type checking and source diagnostics. ordinary calls in an implicit guard stay runtime; use `$()` to request their evaluation. optional captures remain runtime, and ordinary nongeneric `if (true)` still checks both bodies.
 
+`compile_error!(message)` requires a compile-time string and reports its owned text at the call site when that body is elaborated. unselected compile-time branches do not report it; ordinary runtime branches remain checked. messages from constant-input procedures retain their bytes through later evaluation, interpreter diagnostics and native executable emission.
+
 `match $(subject) { ... }` selects an expression or statement arm before specializing or checking its body, including ordinary constant-input calls. concrete generic procedures also select matches on side-effect-free constant subjects, including substituted scalar/enum/tagged-union arguments and pure field/index projections. ordinary checked IR validates every pattern and capture declaration before selection; only the selected body is elaborated, while all bodies remain parsed and name-resolved. by-value payload captures retain exact types and owned strings, and selected bodies may use runtime parameters, nested matches, cleanup, returns and enclosing-loop transfers. ordinary call subjects, runtime parameters and mutable locals stay runtime, as do contextual aggregate bindings that might omit runtime defaults; ordinary nongeneric literal matches still check all arms. use `$()` to request explicit evaluation. pointer/slice/callback-bearing payloads retain the escape boundary above.
 
 type `==` and `!=` comparisons in compile-time expressions and specializations preserve aliases, nominal declaration identity and structural pointer/array/callback signatures. composed error-set identity and specialization caching ignore member ordering, grouping and repetition. for example, `read proc($T type, value T) i16 { if (T == i16) return value else return value.count }` checks the scalar or record path for each concrete call without requiring both operations on every `T`.
@@ -192,7 +194,9 @@ fallible values use explicit `T ! E` channels, where `E` is an enum, record or t
 
 native external declarations use `malloc c_func(size c_ulong) ?*mut anyopaque`, without a body. supported signatures contain concrete integer/float/boolean scalars, data/function pointers, nullable pointers and `void` results. generated bindings may declare `c_struct` records, nominal pointer-only `opaque` types and `*c_func(...) Result` callback signatures. unused foreign declarations do not force ABI validation or native symbol emission; demanding a variadic or aggregate-by-value signature diagnoses unsupported operands. Darwin `c_char`/`c_uchar`, `c_short`/`c_ushort`, `c_int`/`c_uint`, `c_long`/`c_ulong` and `c_longlong`/`c_ulonglong` map to the corresponding 8/16/32/64-bit integer representations; `c_double` maps to `f64`, while demanded `c_float` and `c_longdouble` types remain unsupported. foreign calls trap only when reached in the interpreter; arbitrary interpreter FFI is not supported.
 
-the existing `std/arraylist` and `std/mem` work without replacement bindings or library code. interpreter/native checks cover initialization, reserve/growth, append/pop/clear, allocation failure without losing the original list, zero-sized elements and deferred cleanup on error. native checks use the real `mem.c_allocator` and imported `ffi/c` declarations for aggregate element storage and over-aligned allocation/reallocation; interpreter allocation checks use a fixed-capacity test allocator, not foreign calls. hash maps, broader metadata operations and formatted IO remain later acceptance gates.
+the existing `std/arraylist` and `std/mem` work without replacement bindings or library code. interpreter/native checks cover initialization, reserve/growth, append/pop/clear, allocation failure without losing the original list, zero-sized elements and deferred cleanup on error. native checks use the real `mem.c_allocator` and imported `ffi/c` declarations for aggregate element storage and over-aligned allocation/reallocation; interpreter allocation checks use a fixed-capacity test allocator, not foreign calls. broader metadata operations and formatted IO remain later acceptance gates.
+
+existing `std/hashmap.HashMap`, `AutoHashMap` and `StringHashMap` execute without replacement library code. checks cover collision chains, zero-hash normalization, growth/rehashing, duplicate-key errors, absent lookups, aggregate copy isolation, allocation failure preserving the map and deferred cleanup. native checks use the real C allocator for integer boundaries, booleans, sparse/aliased enums, nested distinct/array/record keys (ignoring record padding), content-based strings and custom callbacks; interpreter checks use separate fixed-capacity typed buffers. pass initializer parameters explicitly, such as `hashmap.init(i16, i16, null, null, allocator)`; initializer inference from an expected result type remains open. a typed `StringHashMap` literal retains its private library callbacks.
 
 records use `Point :: struct { x i16, y i16 = 2 }`, with comma- or newline-separated fields. named record declarations have nominal identity; two separately declared records are not interchangeable. construct them with `Point { x = 40 }` or a contextual keyed literal, such as `point Point := { x = 40 }`. omitted fields use their declared defaults; missing required fields, duplicate/unknown fields, incompatible values and recursive by-value layouts are diagnosed. explicit initializers run in source order, followed by omitted defaults in declaration order. an explicit value overrides its field's default without evaluating that default.
 
@@ -225,6 +229,10 @@ composed error sets use the same inline arms, including through `catch |err| mat
 
 `while` repeats a block or single statement while its `bool` condition holds, re-evaluating the condition on every iteration. guards follow the same braced/braceless convention as `if`. loop bodies introduce child scopes; their locals, including locals in nested conditional arms, begin uninitialized on each scope entry.
 
+a literal `while true` without a reachable break is terminal, including when only nested loops break. nonvoid functions need no fallthrough return after it; runtime guards and loops with reachable breaks still require a return.
+
+`unreachable` is an operand-free statement that traps only when reached, preserving its source location in interpreted, native and compile-time execution. untaken and unused occurrences do not diagnose. it is a fatal trap, not a source error value or a cleanup transfer; it does not execute deferred cleanup.
+
 `for 0..10 |i| { ... }` iterates an ascending, upper-exclusive integer range; `..=` includes the upper bound. a capture is required: `|i|` binds an immutable value with the bounds' exact integer type in the body scope, while `|_|` discards it. bounds resolve in the enclosing scope and are evaluated left-to-right once, so changing a bound variable in the body does not change the range. reversed ranges are empty; equal bounds produce zero iterations with `..` and one with `..=`. inclusive ranges terminate safely at the maximum of each integer type.
 
 range bounds that are compound or unary expressions require their own parentheses, such as `(-2)..(limit + 1)`. a braceless body also requires parentheses around the entire iterable: `for (0..10) |i| total = total + i`. first-class range values and range pointer/index captures remain unimplemented. [programs/range_loop.hon](programs/range_loop.hon) skips `5` while summing `0..10`; `./build/honey run programs/range_loop.hon` prints `40`.

TODO.md

@@ -56,6 +56,12 @@ runtime `undefined` locals and compute fully initialized materializable constant
 the existing `ArrayList` uses nested generic inference, file-local helpers and
 the real imported C allocator through native execution; interpreter checks use
 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.
+`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
 runtime/constant values, contextual optional/fallible results and generated types.
 yielding value blocks, match arms and catch handlers copy results before scoped
@@ -133,7 +139,8 @@ 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.
-  - [ ] remaining gate: general type-valued compile-time execution, broader constant materialization (including untagged unions and storage-bearing values), plus full existing-library acceptance for hash maps, 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 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.
 - [ ] 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.

source/ast/ast.hon

@@ -14,7 +14,7 @@
 #! * arm ...... -> block | stmt (single statements become canonical blocks)
 #! * match_arm -> (expr {',' expr} ['|' identifier '|'] | 'else') ':' (block | stmt | expr); arms are comma/newline separated.
 #! enum members and tagged-union variants accept keyword names; member names do not enter lexical scopes.
-#! * stmt ..... -> decl | expr | block | ('defer' | 'errdefer' ['|' identifier '|']) arm | expr assignment_op expr | 'return' [expr] | 'yield' expr | 'break' | 'continue' | 'if' expr ['|' identifier '|'] arm ['else' arm] | 'while' expr ['|' identifier '|'] arm | ['inline'] 'for' expr '|' ['@'] identifier [',' identifier] '|' arm
+#! * stmt ..... -> decl | expr | block | ('defer' | 'errdefer' ['|' identifier '|']) arm | expr assignment_op expr | 'return' [expr] | 'yield' expr | 'break' | 'continue' | 'unreachable' | 'if' expr ['|' identifier '|'] arm ['else' arm] | 'while' expr ['|' identifier '|'] arm | ['inline'] 'for' expr '|' ['@'] identifier [',' identifier] '|' arm
 #! assignment_op is '=' or a contiguous compound: '+=', '-=', '*=', '/=', '&=', '|=', 'xor=', '<<=', '>>=', '<<|='.
 #! braceless guards/iterables require parentheses unless they are calls, explicit comptime expressions or optional captures; else binds to the nearest if. bitwise-OR headers require parentheses before captures.
 #! precedence (tightest first): calls/indices/selections/dereference/unwrap, unary -, !, ~, &, try higher than multiplication/division, addition/subtraction, shifts << / >> / <<|, bitwise &/xor/|, relational comparisons, equality, and, or, ranges/catch. type composition | binds tighter than fallible !; pointer/optional/array prefixes bind to type atoms. compound range endpoints require their own parentheses.
@@ -104,6 +104,7 @@ StmtKind :: enum {
     yield_stmt
     break_stmt
     continue_stmt
+    unreachable_stmt
     if_stmt
     while_stmt
     for_stmt
@@ -201,6 +202,7 @@ NodeKind :: enum {
     literal_undefined
     expr_block
     stmt_yield
+    stmt_unreachable
 }
 
 @hide:file
@@ -999,6 +1001,10 @@ add_continue_stmt proc(builder @mut Builder, span Span) NodeId ! mem.AllocError
     return try add_node(builder, Node{ kind = .stmt_continue }, span)
 }
 
+add_unreachable_stmt proc(builder @mut Builder, span Span) NodeId ! mem.AllocError {
+    return try add_node(builder, Node{ kind = .stmt_unreachable }, span)
+}
+
 add_if_stmt proc(
     builder @mut Builder,
     span Span,
@@ -1352,6 +1358,7 @@ stmt_kind proc(tree @Tree, id NodeId) StmtKind {
         .stmt_yield: .yield_stmt
         .stmt_break: .break_stmt
         .stmt_continue: .continue_stmt
+        .stmt_unreachable: .unreachable_stmt
         .stmt_if: .if_stmt
         .stmt_assignment: .assignment_stmt
         .stmt_while: .while_stmt
@@ -2060,7 +2067,7 @@ node_layout proc(node Node) NodeLayout {
             if (node.kind == .stmt_defer or node.kind == .stmt_errdefer)
                 layout.direct_children = 3
         }
-        .stmt_break, .stmt_continue, .invalid_stmt: layout.class = .statement
+        .stmt_break, .stmt_continue, .stmt_unreachable, .invalid_stmt: layout.class = .statement
         .stmt_assignment: {
             layout.class = .statement
             layout.direct_children = 3

source/ast/renderer/renderer.hon

@@ -65,6 +65,7 @@ render_block proc(renderer @mut Renderer, tree @ast.Tree, block ast.NodeId, dept
             }
             .break_stmt: try append_text(renderer, "break\n")
             .continue_stmt: try append_text(renderer, "continue\n")
+            .unreachable_stmt: try append_text(renderer, "unreachable\n")
             .block_stmt: {
                 try append_text(renderer, "block\n")
                 try render_block(renderer, tree, ast.statement_block(tree, statement), depth + 1)

source/diagnostics/diagnostics.hon

@@ -127,11 +127,15 @@ Code :: enum {
     invalid_metadata_abi
     invalid_undefined
     invalid_shift_count
+    unreachable_executed
+    compile_error
+    invalid_compile_error
 }
 
 Diagnostic :: struct {
     code Code
     span Span
+    custom_message ?[]u8 = null
 }
 
 #! owns diagnostic storage and retains its allocator; release with deinit.
@@ -146,6 +150,9 @@ init proc(allocator mem.Allocator) Store {
 
 #! releases diagnostic storage with the retained allocator.
 deinit proc(store @mut Store) void {
+    for (store.list.items) |diagnostic| {
+        if (diagnostic.custom_message) |text| mem.free(store.list.allocator, text)
+    }
     arraylist.deinit(&store.list)
 }
 
@@ -157,6 +164,22 @@ add proc(store @mut Store, code Code, span Span) DiagnosticId ! (mem.AllocError
     return id
 }
 
+#! copies `text`; the store owns the message until deinit.
+add_message proc(store @mut Store, code Code, span Span, text []u8) DiagnosticId ! (mem.AllocError | CapacityError) {
+    owned :: try mem.alloc(u8, store.list.allocator, text.len)
+    errdefer mem.free(store.list.allocator, owned)
+    memcopy!(owned, text)
+    id :: try add(store, code, span)
+    store.list.items[usize(id)].custom_message = owned
+    return id
+}
+
+#! borrows either the store-owned custom message or process-lifetime code text.
+message proc(diagnostic Diagnostic) []u8 {
+    if (diagnostic.custom_message) |text| return text
+    return enummap.get(Code, []u8, &messages, diagnostic.code)?
+}
+
 get proc(store @Store, id DiagnosticId) ?Diagnostic {
     if (usize(id) >= store.list.items.len) return null
     return store.list.items[usize(id)]
@@ -185,6 +208,7 @@ messages :: $enummap.init(Code, []u8, {
     argument_count_mismatch = "argument count does not match the function signature",
     cannot_infer_type = "cannot infer a type without a type anchor",
     missing_return = "nonvoid function can finish without returning a value",
+    unreachable_executed = "reached unreachable statement",
     return_type_mismatch = "return does not match the function result type",
     yield_outside_block = "yield requires an enclosing value block",
     missing_yield = "nonvoid value block can finish without yielding a value",
@@ -275,5 +299,7 @@ messages :: $enummap.init(Code, []u8, {
     missing_metadata_import = "typeinfo! requires importing @std/meta",
     invalid_metadata_abi = "@std/meta declarations do not match the compiler reflection ABI",
     invalid_undefined = "undefined requires a concrete mutable local declaration",
+    compile_error = "explicit compile-time error",
+    invalid_compile_error = "compile_error! requires one compile-time string argument",
 })
 

source/interpreter/interpreter.hon

@@ -191,7 +191,7 @@ execute proc(
         if instruction_index == block.instructions.items.len {
             terminator :: block.terminator
             if (terminator.kind == .trap) return Outcome{ trap = terminator.diagnostic }
-            if (terminator.kind == .unreachable) unreachable
+            if (terminator.kind == .unreachable) return try runtime_trap(diagnostic_store, .unreachable_executed, terminator.span)
             if (terminator.kind == .jump or terminator.kind == .branch) {
                 target := terminator.target
                 if (terminator.kind == .branch) {

source/lexer/scan.hon

@@ -29,6 +29,7 @@ keywords strmap.StaticStringMap(TokenKind) :: strmap.init([
     { "yield", .yield },
     { "break", .break },
     { "continue", .continue },
+    { "unreachable", .unreachable },
     { "try", .try },
     { "catch", .catch },
     { "defer", .defer },

source/lexer/token.hon

@@ -25,6 +25,7 @@ TokenKind :: enum {
     proc, return
     yield
     break, continue
+    unreachable
     try, catch
     defer, errdefer
     true, false

source/llvm/llvm.hon

@@ -61,7 +61,7 @@ emit proc(
     }
     for (diagnostic_store.list.items) |diagnostic, index| {
         try io.print("@d{} = private constant ", output, {index})
-        try bytes_constant(output, enummap.get(diagnostics.Code, []u8, &diagnostics.messages, diagnostic.code)?, false)
+        try bytes_constant(output, diagnostics.message(diagnostic), false)
         try io.write_all(output, "\n")
     }
     memory_codes [_]diagnostics.Code :: [
@@ -69,6 +69,7 @@ emit proc(
         .overlapping_memory_copy, .unsupported_foreign_call, .invalid_pointer_access,
         .division_by_zero,
         .invalid_shift_count,
+        .unreachable_executed,
     ]
     for (memory_codes) |code| {
         try io.print("@memory_{s} = private constant ", output, {enummap.get(&memory_symbols, code)?})
@@ -321,7 +322,7 @@ emit_reporting proc(
     try io.write_all(output, "define internal void @report(i64 %trap) {\nentry:\n")
     for (diagnostic_store.list.items) |diagnostic, index| {
         position :: location(line_starts, diagnostic.span)
-        message :: enummap.get(diagnostics.Code, []u8, &diagnostics.messages, diagnostic.code)?
+        message :: diagnostics.message(diagnostic)
         try io.print("  %t{} = icmp eq i64 %trap, {}\n", output, {index, index})
         try io.print("  call void @diagnose(i64 {}, i64 {}, i64 {}, ptr @d{}, i64 {}, i1 %t{})\n", output, {
             usize(diagnostic.span.source), position.line, position.column, index, message.len, index,
@@ -511,6 +512,7 @@ memory_symbols :: $enummap.init_default(diagnostics.Code, []u8, "", {
     invalid_pointer_access = "invalid_pointer_access",
     division_by_zero = "division_by_zero",
     invalid_shift_count = "invalid_shift_count",
+    unreachable_executed = "unreachable_executed",
 })
 
 @hide:file
@@ -650,7 +652,7 @@ emit_function proc(state @mut State, function @ir.Function, id usize) void ! io.
                 }
             }
             .trap: try io.print("  call void @trap(i64 {}, i64 0, i64 0, i64 0, ptr null, i64 0)\n  unreachable\n", output, {u32(terminator.diagnostic)})
-            .unreachable: try io.write_all(output, "  unreachable\n")
+            .unreachable: try trap(state, .unreachable_executed, terminator.span)
             .jump: try io.print("  br label %b{}\n", output, {u32(terminator.target)})
             .branch: {
                 condition :: try load(state, terminator.value)

source/lower/lower.hon

@@ -23,6 +23,7 @@ LoopTargets :: struct {
     continue_target ir.BlockId
     exit ir.BlockId
     cleanup_depth usize
+    break_reached bool = false
 }
 
 @hide:file
@@ -770,7 +771,14 @@ lower_while proc(state @mut State, id ast.NodeId) void ! (mem.AllocError | diagn
         }
     }
     state.block = exit
-    state.terminated = false
+    state.terminated = (
+        loop.capture == null
+        and ast.expr_kind(state.tree, loop.condition) == .literal_bool
+        and mem.eql(ast.literal_text(state.tree, loop.condition), "true")
+        and !state.loop?.break_reached
+    )
+    if (state.terminated)
+        state.module.functions.items[state.function].blocks.items[usize(exit)].terminator = ir.Terminator{ kind = .unreachable, span = loop.span }
 }
 
 @hide:file
@@ -920,6 +928,12 @@ lower_statement proc(state @mut State, id ast.NodeId) void ! (mem.AllocError | d
         .if_stmt: try lower_if(state, id)
         .while_stmt: try lower_while(state, id)
         .for_stmt: try lower_for(state, id)
+        .unreachable_stmt: {
+            state.module.functions.items[state.function].blocks.items[usize(state.block)].terminator = ir.Terminator{
+                kind = .unreachable, span = ast.node_span(tree, id),
+            }
+            state.terminated = true
+        }
         .break_stmt, .continue_stmt: {
             if (trap_type(state, id)) return
             if (state.loop) |targets| {
@@ -928,6 +942,11 @@ lower_statement proc(state @mut State, id ast.NodeId) void ! (mem.AllocError | d
                 if (ast.stmt_kind(tree, id) == .continue_stmt) target = targets.continue_target
                 try lower_cleanups(state, targets.cleanup_depth, ir.no_value)
                 if (state.terminated) return
+                if (ast.stmt_kind(tree, id) == .break_stmt) {
+                    reached := targets
+                    reached.break_reached = true
+                    state.loop = reached
+                }
                 state.module.functions.items[state.function].blocks.items[usize(state.block)].terminator = ir.Terminator{
                     kind = .jump, target = target, span = ast.node_span(tree, id),
                 }

source/lower/lower.test.hon

@@ -992,7 +992,7 @@ zero_iteration_body_errors_are_checked_but_not_executed test {
     }
 }
 
-loop_returns_do_not_guarantee_return_and_assignment_arithmetic_still_checks_overflow test {
+terminal_true_loops_and_assignment_arithmetic_preserve_runtime_behavior test {
     sources [5][]u8 :: [
         "main proc() int {\n while true { return 42 }\n}\n",
         "main proc() int {\n while false { return 42 }\n}\n",
@@ -1005,7 +1005,7 @@ loop_returns_do_not_guarantee_return_and_assignment_arithmetic_still_checks_over
         defer diagnostics.deinit(&diagnostic_store)
         module := try compile_owned(source, &diagnostic_store)
         defer ir.deinit(&module)
-        if (index != 2) {
+        if (index != 0 and index != 2) {
             try testing.expect_equal(1, diagnostics.count(&diagnostic_store))
             diagnostic :: diagnostics.get(&diagnostic_store, diagnostics.DiagnosticId(0))?
             try testing.expect_equal(diagnostics.Code.missing_return, diagnostic.code)

source/main.hon

@@ -288,7 +288,7 @@ report_diagnostics proc(
                 line + 1,
                 offset - starts[line] + 1,
                 label,
-                enummap.get(diagnostics.Code, []u8, &diagnostics.messages, diagnostic.code)?,
+                diagnostics.message(diagnostic),
             })
         }
     }

source/parser/parse.hon

@@ -323,7 +323,7 @@ parse_statement proc(state @mut State, allow_else bool) ast.NodeId ! ParseError
         .for, .inline: return try parse_for(state, allow_else)
         .return: return try parse_return(state, allow_else)
         .yield: return try parse_yield(state, allow_else)
-        .break, .continue: return try parse_loop_control(state, allow_else)
+        .break, .continue, .unreachable: return try parse_loop_control(state, allow_else)
         .defer, .errdefer: return try parse_cleanup(state, allow_else)
         .open_curly: return try ast.add_block_stmt(state.builder, try parse_block(state))
         .ident, .int, .float, .string, .true, .false, .minus, .bang, .tilde, .open_paren, .open_bracket, .struct, .c_struct, .opaque, .c_func,
@@ -426,6 +426,8 @@ parse_loop_control proc(state @mut State, allow_else bool) ast.NodeId ! ParseErr
 
     if (keyword.kind == .break)
         return try ast.add_break_stmt(state.builder, keyword.span)
+    if (keyword.kind == .unreachable)
+        return try ast.add_unreachable_stmt(state.builder, keyword.span)
 
     return try ast.add_continue_stmt(state.builder, keyword.span)
 }
@@ -688,6 +690,7 @@ parse_guard proc(state @mut State) ast.NodeId ! ParseError {
             and !next_is(state, .if) and !next_is(state, .while)
             and !next_is(state, .for) and !next_is(state, .inline)
             and !next_is(state, .break) and !next_is(state, .continue)
+            and !next_is(state, .unreachable)
         ) {
             if (next_is(state, .ident) and is_assignment_operator(state.tokens[state.next_token + 1].kind)) break
             state.next_token += 1
@@ -958,7 +961,7 @@ member_names :: $enummap.init_default(lexer.TokenKind, bool, false, {
     struct = true, c_struct = true, opaque = true, enum = true, union = true,
     distinct = true, alias = true, match = true, import = true, test = true,
     c_func = true, null = true, undefined = true, try = true, catch = true,
-    defer = true, errdefer = true,
+    defer = true, errdefer = true, unreachable = true,
 })
 
 @hide:file
@@ -1192,7 +1195,7 @@ parse_match_arm proc(state @mut State) ast.NodeId ! ParseError {
     state.match_arm_body = true
     defer state.match_arm_body = previous
     statement_body :: match current(state).kind {
-        .open_curly, .return, .yield, .break, .continue, .if, .while, .for, .inline, .defer, .errdefer: true
+        .open_curly, .return, .yield, .break, .continue, .unreachable, .if, .while, .for, .inline, .defer, .errdefer: true
         else: false
     }
     body ast.NodeId := undefined
@@ -1773,7 +1776,7 @@ brace_starts_block proc(state @State) bool {
         if (kind == .eof) return false
         if (depth > 0
             and (state.tokens[first].kind == .if or state.tokens[first].kind == .open_curly)
-            and (kind == .yield or kind == .return or kind == .defer or kind == .errdefer)
+            and (kind == .yield or kind == .return or kind == .unreachable or kind == .defer or kind == .errdefer)
             and state.tokens[index - 1].kind != .dot
             and !(index + 1 < state.tokens.len and state.tokens[index + 1].kind == .equal)) return true
         if (depth == 1) {
@@ -1782,7 +1785,7 @@ brace_starts_block proc(state @State) bool {
             previous :: if (index > first) state.tokens[index - 1].kind else lexer.TokenKind.open_curly
             if (previous != .dot and !(index + 1 < state.tokens.len and state.tokens[index + 1].kind == .equal)) {
                 match kind {
-                    .yield, .return, .break, .continue, .while, .for, .inline, .defer, .errdefer: return true
+                    .yield, .return, .break, .continue, .unreachable, .while, .for, .inline, .defer, .errdefer: return true
                     else: {}
                 }
             }
@@ -1914,7 +1917,7 @@ parse_primary proc(state @mut State) ast.NodeId ! ParseError {
 @hide:file
 is_expression_boundary proc(kind lexer.TokenKind) bool {
     return match kind {
-        .close_paren, .newline, .close_curly, .open_curly, .else, .return, .yield, .if, .while, .for, .inline, .defer, .errdefer, .eof: true
+        .close_paren, .newline, .close_curly, .open_curly, .else, .return, .yield, .unreachable, .if, .while, .for, .inline, .defer, .errdefer, .eof: true
         else: false
     }
 }
@@ -2054,7 +2057,7 @@ recovery_closes_delimiters proc(state @State, paren_depth, square_depth usize) b
         kind :: state.tokens[i].kind
         match kind {
             .open_curly, .close_curly, .eof, .if, .else, .while, .for, .inline,
-            .return, .break, .continue, .defer, .errdefer: return false
+            .return, .break, .continue, .unreachable, .defer, .errdefer: return false
             .ident: {
                 if (i + 1 < state.tokens.len) {
                     next :: state.tokens[i + 1].kind

source/sema/check/check.hon

@@ -1101,6 +1101,7 @@ collect_block proc(state @mut State, id, return_annotation ast.NodeId, in_loop b
                 try collect_declaration(state, statement)
             }
             .expression: try collect_expression(state, ast.statement_expr(tree, statement))
+            .unreachable_stmt: state.cells[usize(statement)].type = Type{ kind = .void }
             .return_stmt: {
                 state.cells[usize(statement)].role = .return_stmt
                 state.cells[usize(statement)].type = Type{ kind = .void }
@@ -2335,6 +2336,7 @@ validate_call proc(state @mut State, id ast.NodeId) void ! (mem.AllocError | dia
 BlockFlow :: struct {
     falls bool = true
     yields bool = false
+    breaks bool = false
 }
 
 @hide:file
@@ -2367,6 +2369,16 @@ expression_falls_through proc(state @State, id ast.NodeId) bool {
     }
 }
 
+@hide:file
+expression_breaks proc(state @State, id ast.NodeId) bool {
+    tree :: state.tree
+    if (ast.node_class(tree, id) == .block) return block_flow(state, id).breaks
+    for 0..ast.child_count(tree, id) |i| {
+        if (expression_breaks(state, ast.child(tree, id, i))) return true
+    }
+    return false
+}
+
 @hide:file
 block_flow proc(state @State, id ast.NodeId) BlockFlow {
     tree :: state.tree
@@ -2381,30 +2393,62 @@ block_flow proc(state @State, id ast.NodeId) BlockFlow {
         }
         match kind {
             .yield_stmt: {
+                if (ast.yield_stmt(tree, statement).value) |value|
+                    result.breaks = result.breaks or expression_breaks(state, value)
                 result.yields = true
                 result.falls = false
             }
-            .return_stmt, .break_stmt, .continue_stmt, .invalid: result.falls = false
+            .return_stmt: {
+                if (ast.return_stmt(tree, statement).value) |value|
+                    result.breaks = result.breaks or expression_breaks(state, value)
+                result.falls = false
+            }
+            .break_stmt: {
+                result.breaks = true
+                result.falls = false
+            }
+            .continue_stmt, .unreachable_stmt, .invalid: result.falls = false
             .block_stmt: {
                 nested :: block_flow(state, ast.statement_block(tree, statement))
                 result.yields = result.yields or nested.yields
+                result.breaks = result.breaks or nested.breaks
                 result.falls = nested.falls
             }
             .if_stmt: {
                 conditional :: ast.if_stmt(tree, statement)
                 then_flow :: block_flow(state, conditional.then_block)
                 result.yields = result.yields or then_flow.yields
+                result.breaks = result.breaks or then_flow.breaks or expression_breaks(state, conditional.condition)
                 if (conditional.else_block) |other| {
                     else_flow :: block_flow(state, other)
                     result.yields = result.yields or else_flow.yields
+                    result.breaks = result.breaks or else_flow.breaks
                     result.falls = then_flow.falls or else_flow.falls
                 }
             }
-            .while_stmt: result.yields = result.yields or block_flow(state, ast.while_stmt(tree, statement).body).yields
+            .while_stmt: {
-            .for_stmt: result.yields = result.yields or block_flow(state, ast.for_stmt(tree, statement).body).yields
+                loop :: ast.while_stmt(tree, statement)
-            .expression: result.falls = expression_falls_through(state, source)
+                body :: block_flow(state, loop.body)
-            .declaration: result.falls = expression_falls_through(state, ast.statement_decl(tree, statement).initializer)
+                result.yields = result.yields or body.yields
-            .assignment_stmt: result.falls = expression_falls_through(state, ast.assignment_stmt(tree, statement).value)
+                result.breaks = result.breaks or expression_breaks(state, loop.condition)
+                if (loop.capture == null and ast.expr_kind(tree, loop.condition) == .literal_bool
+                    and mem.eql(ast.literal_text(tree, loop.condition), "true"))
+                    result.falls = body.breaks
+            }
+            .for_stmt: {
+                loop :: ast.for_stmt(tree, statement)
+                result.yields = result.yields or block_flow(state, loop.body).yields
+                result.breaks = result.breaks or expression_breaks(state, loop.iterable)
+            }
+            .expression, .declaration, .assignment_stmt: {
+                value :: if (kind == .expression) source
+                    else if (kind == .declaration) ast.statement_decl(tree, statement).initializer
+                    else ast.assignment_stmt(tree, statement).value
+                result.breaks = result.breaks or expression_breaks(state, value)
+                if (kind == .assignment_stmt)
+                    result.breaks = result.breaks or expression_breaks(state, ast.assignment_stmt(tree, statement).target)
+                result.falls = expression_falls_through(state, value)
+            }
             else: {}
         }
         if (!result.falls) return result

source/sema/check/check.test.hon

@@ -684,7 +684,7 @@ return_errors_preserve_identity_check_unreachable_code_and_suppress_missing_retu
         `void_value proc() void { return 1 }
         `unknown proc() int { return absent }
         `syntax proc() int { return (1 }
-        `unreachable proc() int {
+        `after_return proc() int {
         `    return 7
         `    -"bad"
         `}
@@ -910,7 +910,7 @@ analyzes_return_paths_after_trap_propagation_without_poisoning_signatures test {
         `syntax_trap proc() int {
         `    return 1 stray
         `}
-        `unreachable proc() int {
+        `after_return proc() int {
         `    return 1
         `    -"bad"
         `}
@@ -1198,7 +1198,7 @@ while_checks_nested_bodies_without_claiming_a_zero_iteration_return test {
     diagnostic_store := diagnostics.init(mem.c_allocator)
     defer diagnostics.deinit(&diagnostic_store)
     source ::
-        `missing proc() int { while true { return 1 } }
+        `terminal proc() int { while true { return 1 } }
         `bad_body proc() int { while false { -"bad" } }
         `continues proc() int {
         `    while false { -"bad" }
@@ -1226,12 +1226,11 @@ while_checks_nested_bodies_without_claiming_a_zero_iteration_return test {
     result := try check(mem.c_allocator, &tree, &resolution, &diagnostic_store)
     defer deinit(&result)
 
-    for usize(0)..usize(2) |index| {
+    terminal :: ast.package_decl(&tree, 0)
-        function :: ast.package_decl(&tree, index)
+    try testing.expect(fallthrough_diagnostic(&result, terminal) == null)
-        body :: ast.function_decl(&tree, function).body
+    body :: ast.function_decl(&tree, ast.package_decl(&tree, 1)).body
-        _ = try expect_fallthrough(&result, &diagnostic_store, function, ast.node_span(&tree, body))
+    _ = try expect_fallthrough(&result, &diagnostic_store, ast.package_decl(&tree, 1), ast.node_span(&tree, body))
     try expect_kind(&result, ast.block_statement(&tree, body, 0), .void)
-    }
     continues_body :: ast.function_decl(&tree, ast.package_decl(&tree, 2)).body
     loop_statement :: ast.block_statement(&tree, continues_body, 0)
     loop :: ast.while_stmt(&tree, loop_statement)
@@ -1261,7 +1260,7 @@ while_checks_nested_bodies_without_claiming_a_zero_iteration_return test {
         try expect_kind(&result, assignment.target, .int)
         try expect_kind(&result, assignment.value, .int)
     }
-    try testing.expect_equal(2, code_count(&diagnostic_store, .missing_return))
+    try testing.expect_equal(1, code_count(&diagnostic_store, .missing_return))
     try testing.expect_equal(1, code_count(&diagnostic_store, .condition_not_bool))
     try testing.expect_equal(3, code_count(&diagnostic_store, .invalid_operand))
 }
@@ -1518,7 +1517,7 @@ short_circuit_skip_paths_do_not_guarantee_a_return test {
         `call proc() int { take(true or 1) }
         `conditional proc() int { if false and missing_condition { return 1 } }
         `loop proc() int { while true or missing_guard { return 1 } }
-        `loop_body proc() int { while true { true or 1 } }
+        `loop_body proc(flag bool) int { while flag { true or 1 } }
         `arms proc(flag bool) int {
         `    if flag { false and missing_arm } else { return 1 }
         `}

source/sema/resolve.hon

@@ -412,7 +412,7 @@ resolve_block proc(state @mut State, scope @mut Scope, id ast.NodeId) void ! (me
                 if (ast.return_stmt(tree, statement).value) |value| try resolve_expr(state, scope, value)
             }
             .yield_stmt: try resolve_expr(state, scope, ast.yield_stmt(tree, statement).value?)
-            .break_stmt, .continue_stmt: {}
+            .break_stmt, .continue_stmt, .unreachable_stmt: {}
             .block_stmt: try resolve_arm(state, scope, ast.statement_block(tree, statement))
             .defer_stmt, .errdefer_stmt: {
                 cleanup :: ast.cleanup_stmt(tree, statement)

source/sema/specialize/specialize.hon

@@ -134,7 +134,8 @@ elaborate proc(
         if (class == .expression and ast.expr_kind(&original, id) == .builtin_call) {
             name :: ast.builtin_call(&original, id).name
             text :: ast.source_text(&original, ast.node_span(&original, name))
-            if (mem.eql(text, "field") or mem.eql(text, "struct_type") or mem.eql(text, "typeinfo")) needed = true
+            if (mem.eql(text, "field") or mem.eql(text, "struct_type") or mem.eql(text, "typeinfo")
+                or mem.eql(text, "compile_error")) needed = true
         }
         if (class == .function and ast.function_generic(&original, id)) needed = true
         if (class == .function) {
@@ -237,6 +238,35 @@ reject proc(state @mut State, id ast.NodeId, code diagnostics.Code) void ! Error
     state.bindings.items[usize(id)] = sema.Binding{ kind = .invalid, data = sema.BindingData{ diagnostic = diagnostic } }
 }
 
+@hide:file
+expand_compile_error proc(state @mut State, id ast.NodeId) void ! Error {
+    if (ast.call_arg_count(&state.tree, id) != 1) {
+        try reject(state, id, .invalid_compile_error)
+        return
+    }
+    state.evaluation_diagnostic = diagnostics.no_diagnostic
+    value :: try evaluate(state, ast.call_arg(&state.tree, id, 0))
+    if (value.kind != .string) {
+        if (state.evaluation_diagnostic != diagnostics.no_diagnostic) try reject_evaluation(state, id)
+        else try reject(state, id, .invalid_compile_error)
+        return
+    }
+    text :: ast.literal_text(&state.tree, value.node)
+    bytes := arraylist.init(u8, state.allocator)
+    defer arraylist.deinit(&bytes)
+    cursor := usize(1)
+    while (cursor < text.len - 1) {
+        byte :: ast.string_next(text, &cursor) catch {
+            try reject(state, id, .invalid_escape)
+            return
+        }
+        try arraylist.append(&bytes, byte)
+    }
+    state.evaluation_diagnostic = try diagnostics.add_message(state.diagnostics,
+        .compile_error, ast.node_span(&state.tree, id), bytes.items)
+    try reject_evaluation(state, id)
+}
+
 @hide:file
 expand proc(state @mut State, id ast.NodeId) void ! Error {
     try refresh(state)
@@ -287,6 +317,15 @@ expand proc(state @mut State, id ast.NodeId) void ! Error {
     if (class == .statement and ast.stmt_kind(&state.tree, id) == .for_stmt) {
         loop :: ast.for_stmt(&state.tree, id)
         try expand(state, loop.iterable)
+        if (loop.index) |capture| {
+            annotation :: try builtin(state, id, .usize)
+            hashmap.put(&state.capture_types, capture, annotation) catch |err| {
+                match err {
+                    .key_exists: {}
+                    else: return err
+                }
+            }
+        }
         if (!loop.pointer_capture and loop.capture != null) {
             iterable :: try expression_type(state, loop.iterable, 0)
             element := no_node
@@ -417,6 +456,10 @@ expand proc(state @mut State, id ast.NodeId) void ! Error {
     }
     if (class == .expression and ast.expr_kind(&state.tree, id) == .builtin_call) {
         name :: ast.builtin_call(&state.tree, id).name
+        if (mem.eql(ast.source_text(&state.tree, ast.node_span(&state.tree, name)), "compile_error")) {
+            try expand_compile_error(state, id)
+            return
+        }
         if (mem.eql(ast.source_text(&state.tree, ast.node_span(&state.tree, name)), "field")) {
             try expand_field(state, id)
             return
@@ -496,7 +539,7 @@ value_block_terminal proc(state @State, id ast.NodeId) bool {
     }
     if (class != .statement) return false
     match ast.stmt_kind(&state.tree, id) {
-        .yield_stmt, .return_stmt, .break_stmt, .continue_stmt: return true
+        .yield_stmt, .return_stmt, .break_stmt, .continue_stmt, .unreachable_stmt: return true
         .block_stmt: return value_block_terminal(state, ast.statement_block(&state.tree, id))
         .if_stmt: {
             view :: ast.if_stmt(&state.tree, id)
@@ -2300,7 +2343,11 @@ evaluate_ir_body proc(state @mut State, at, body, result_type ast.NodeId) Value
     diagnostic_store := diagnostics.init(state.allocator)
     defer diagnostics.deinit(&diagnostic_store)
     # Resolution's existing diagnostic IDs remain valid in this temporary store.
-    for (state.diagnostics.list.items) |diagnostic| try arraylist.append(&diagnostic_store.list, diagnostic)
+    for (state.diagnostics.list.items) |diagnostic| {
+        if (diagnostic.custom_message) |text| {
+            _ = try diagnostics.add_message(&diagnostic_store, diagnostic.code, diagnostic.span, text)
+        } else _ = try diagnostics.add(&diagnostic_store, diagnostic.code, diagnostic.span)
+    }
     original_diagnostics :: diagnostics.count(&diagnostic_store)
     checked := try typecheck.check(state.allocator, &tree, state.resolution, &diagnostic_store)
     defer typecheck.deinit(&checked)
@@ -2744,6 +2791,7 @@ inline_statement proc(state @mut State, id ast.NodeId) TypeFlow ! Error {
     kind :: ast.stmt_kind(&state.tree, id)
     if (kind == .break_stmt) return .break
     if (kind == .continue_stmt) return .continue
+    if (kind == .unreachable_stmt) return .returned
     if (kind == .yield_stmt or kind == .return_stmt) {
         try expand(state, id)
         return if (kind == .yield_stmt) TypeFlow.yielded else TypeFlow.returned
@@ -3911,6 +3959,11 @@ execute_type_statement proc(state @mut State, execution @mut TypeExecution, stat
 @hide:file
 execute_type_statement_body proc(state @mut State, execution @mut TypeExecution, statement ast.NodeId) TypeFlow ! Error {
     match ast.stmt_kind(&state.tree, statement) {
+        .unreachable_stmt: {
+            state.evaluation_diagnostic = try diagnostics.add(state.diagnostics,
+                .unreachable_executed, ast.node_span(&state.tree, statement))
+            return .invalid
+        }
         .defer_stmt: {}
         .errdefer_stmt: {
             state.evaluation_diagnostic = try diagnostics.add(state.diagnostics,
@@ -4465,6 +4518,18 @@ evaluate proc(state @mut State, id ast.NodeId) Value ! Error {
             view :: ast.unary_expr(&state.tree, id)
             if (view.operator == .bit_not)
                 return try evaluate_ir(state, id, try expression_type(state, id, 0))
+            if (view.operator == .unwrap) {
+                # source-known callbacks already own declaration identities, not interpreter handles.
+                value := try evaluate(state, view.operand)
+                annotation :: try expression_type(state, view.operand, 0)
+                if (value.kind == .function and annotation != no_node
+                    and ast.expr_kind(&state.tree, annotation) == .optional_type) {
+                    try arraylist.append(&state.rewrites.constraints, id)
+                    value.annotation = ast.type_operand(&state.tree, annotation)
+                    return value
+                }
+                return try evaluate_ir(state, id, try expression_type(state, id, 0))
+            }
             value := try evaluate(state, view.operand)
             if (view.operator == .negate and value.kind == .integer) value.negative = value.magnitude != 0 and !value.negative
             else if (view.operator == .negate and value.kind == .real) value.magnitude = value.magnitude xor (u64(1) << 63)
@@ -4917,6 +4982,8 @@ expression_type proc(state @mut State, id ast.NodeId, depth usize) ast.NodeId !
                 return try builtin(state, id, .usize)
             if ((mem.eql(name, "maxval") or mem.eql(name, "minval")) and count == 1)
                 return try canonical_type(state, ast.call_arg(&state.tree, id, 0))
+            if ((mem.eql(name, "ptrcast") or mem.eql(name, "constcast")) and count == 2)
+                return try canonical_type(state, ast.call_arg(&state.tree, id, 0))
             if (mem.eql(name, "divtrunc") and count == 2) {
                 left :: ast.call_arg(&state.tree, id, 0)
                 right :: ast.call_arg(&state.tree, id, 1)
@@ -4974,6 +5041,7 @@ expression_type proc(state @mut State, id ast.NodeId, depth usize) ast.NodeId !
             if (destination.kind == .builtin) return callee
             if (destination.kind == .declaration and ast.node_class(&state.tree, destination.data.declaration) == .function) return try canonical_type(state, ast.function_decl(&state.tree, destination.data.declaration).return_type)
             signature :: try expression_type(state, callee, depth + 1)
+            if (signature != no_node and is_type(state, signature)) return try canonical_type(state, callee)
             if (signature != no_node and ast.expr_kind(&state.tree, signature) == .function_type)
                 return try canonical_type(state, ast.callable_result(&state.tree, signature))
             return no_node
@@ -5121,8 +5189,18 @@ infer_value proc(state @mut State, function, pattern ast.NodeId, actual Value, a
 @hide:file
 infer proc(state @mut State, function, pattern, actual ast.NodeId, arguments []mut Value, contextual bool) bool ! Error {
     resolved :: binding(state, pattern)
-    if (resolved.kind == .declaration and parameter_index(state, function, resolved.data.declaration) != no_index)
+    if (resolved.kind == .declaration) {
+        index :: parameter_index(state, function, resolved.data.declaration)
+        if (index != no_index) {
+            if (arguments[index].kind == .type) {
+                expected :: try canonical_type(state, arguments[index].node)
+                # a fixed slice type supplies borrowing/string context; ordinary
+                # argument checking owns element, mutability and sentinel validation.
+                if (expected != no_node and ast.expr_kind(&state.tree, expected) == .slice_type) return true
+            }
             return try infer_value(state, function, pattern, Value{ kind = .type, node = actual }, arguments, contextual)
+        }
+    }
     # only normalize the actual type: the pattern may still contain unbound
     # parameters or a type-generator call whose arguments must be inferred.
     concrete :: try canonical_type(state, actual)

std/hashmap/hashmap.hon

@@ -110,10 +110,10 @@ put proc(
         for old_entries |entry| {
             if (entry.hash == 0) continue
 
-            idx := entry.hash & (new_entries.len - 1)
+            rehash_index := entry.hash & (new_entries.len - 1)
-            while (new_entries[idx].hash != 0) idx = (idx + 1) & (new_entries.len - 1)
+            while (new_entries[rehash_index].hash != 0) rehash_index = (rehash_index + 1) & (new_entries.len - 1)
 
-            new_entries[idx] = entry
+            new_entries[rehash_index] = entry
         }
 
         map.entries = new_entries
@@ -176,7 +176,7 @@ str_hash proc(key []u8) usize {
     prime u32 :: 16777619
 
     for key |byte| {
-        product u64 :: u64(hash xor u32(byte)) * prime
+        product u64 :: u64(hash xor u32(byte)) * u64(prime)
         hash = u32(product & u64(maxval!(u32)))
     }
 

tests/native.py

@@ -11,6 +11,93 @@ HONEY = ROOT / "build/honey"
 
 # Explicit expectations guard against frontend bugs shared by both execution paths.
 CASES = {
+    "unreachable_is_a_demanded_source_trap_without_cleanup": (
+        """
+        fail proc() i16 {
+            defer unreachable
+            unreachable
+        }
+        main proc() i16 { return fail() }
+        """, b"", b":3:5: runtime trap: reached unreachable statement",
+    ),
+    "untaken_and_unused_unreachable_do_not_diagnose": (
+        """
+        unused proc() i16 { unreachable }
+        choose proc(flag bool) i16 {
+            if (flag) unreachable
+            return match flag { true: unreachable, false: 42 }
+        }
+        main proc() i16 { return choose(false) }
+        """, b"42\n", None,
+    ),
+    "unreachable_traps_only_selected_constant_execution": (
+        """
+        choose proc(flag bool) i16 {
+            if (flag) unreachable
+            return 42
+        }
+        main proc() i16 { return $(choose(false)) }
+        """, b"42\n", None,
+    ),
+    "unreachable_constant_execution_preserves_source": (
+        """
+        fail proc() i16 {
+            unreachable
+        }
+        main proc() i16 { return $(fail()) }
+        """, b"", b":2:5: runtime trap: reached unreachable statement",
+    ),
+    "terminal_while_true_preserves_nested_breaks_and_cleanups": (
+        """
+        compute proc(trace @mut i16) i16 {
+            while true {
+                defer trace^ += 1
+                while true { break }
+                if (trace^ == 2) return 42
+                continue
+            }
+        }
+        main proc() [2]i16 {
+            trace i16 := 0
+            answer :: compute(&trace)
+            return [answer, trace]
+        }
+        """, b"[42, 3]\n", None,
+    ),
+    "terminal_while_true_return": (
+        "main proc() i16 { while true { return 42 } }",
+        b"42\n", None,
+    ),
+    "terminal_while_true_constant_execution": (
+        "compute proc() i16 { while true { return 42 } }\nmain proc() i16 { return $(compute()) }",
+        b"42\n", None,
+    ),
+    "terminal_while_true_ignores_break_after_return": (
+        "main proc() i16 { while true { return 42\nbreak } }",
+        b"42\n", None,
+    ),
+    "while_true_break_requires_return": (
+        "main proc() i16 { while true { break } }",
+        b"", b"nonvoid function can finish without returning a value",
+    ),
+    "while_true_value_block_break_requires_return": (
+        """
+        main proc() i16 {
+            while true {
+                value i16 :: { break }
+                _ = value
+            }
+        }
+        """, b"", b"nonvoid function can finish without returning a value",
+    ),
+    "while_runtime_guard_still_requires_return": (
+        "main proc() i16 { flag := true\nwhile flag { return 42 } }",
+        b"42\n", b"nonvoid function can finish without returning a value",
+    ),
+    "unreachable_rejects_trailing_operand": (
+        "main proc() i16 { unreachable 42 }",
+        b"", b"unexpected token",
+    ),
     "distinct_bitwise_results_preserve_nominal_type": (
         """
         Flags :: distinct u16
@@ -7334,6 +7421,126 @@ CASES = {
     "invalid_unused_signature": (
         "bad proc(a void) void {}\nmain proc() int { return 42 }", b"42\n", b"void cannot be stored",
     ),
+    "optional_compile_time_callbacks_preserve_source_identity": (
+        """
+        first proc(value i16) i16 { return value }
+        second proc(value i16) i16 { return value + 2 }
+        invoke proc($callback proc(value i16) i16, value i16) i16 { return callback(value) }
+        choose proc($callback ?proc(value i16) i16, value i16) i16 {
+            if $(callback == null) return value + 3
+            else return invoke(callback?, value)
+        }
+        main proc() [3]i16 { return [choose(first, 42), choose(second, 40), choose(null, 39)] }
+        """, b"[42, 42, 42]\n", None,
+    ),
+    "null_compile_time_callback_unwrap_traps": (
+        """
+        invoke proc($callback proc() i16) i16 { return callback() }
+        choose proc($callback ?proc() i16) i16 { return invoke(callback?) }
+        main proc() i16 { return choose(null) }
+        """, b"", b"null optional",
+    ),
+    "compile_error_reports_owned_computed_message": (
+        """
+        explain proc() string { return "invalid \\"key\\"" }
+        fail proc($bad bool) i16 {
+            if (bad) compile_error!(explain())
+            return 42
+        }
+        main proc() i16 { return fail(true) }
+        """, b"", b'invalid "key"',
+    ),
+    "compile_error_skips_unselected_generic_and_type_bodies": (
+        """
+        choose proc($bad bool) i16 {
+            if (bad) compile_error!("wrong branch")
+            return 42
+        }
+        Storage proc(bad bool) type {
+            if (bad) compile_error!("wrong type branch")
+            return i16
+        }
+        main proc() Storage(false) { return choose(false) }
+        """, b"42\n", None,
+    ),
+    "compile_error_type_execution_preserves_message": (
+        """
+        Storage proc(bad bool) type {
+            if (bad) compile_error!("invalid generated storage")
+            return i16
+        }
+        main proc() Storage(true) { return 42 }
+        """, b"", b"invalid generated storage",
+    ),
+    "compile_error_custom_diagnostics_survive_later_evaluation": (
+        """
+        unused proc() void { compile_error!("retained message") }
+        compute proc() i16 { return 42 }
+        main proc() i16 { return $(compute()) }
+        """, b"42\n", b"error: retained message",
+    ),
+    "compile_error_rejects_runtime_messages": (
+        """
+        fail proc(message string) void { compile_error!(message) }
+        main proc() i16 { fail("not constant")\nreturn 42 }
+        """, b"", b"compile_error! requires one compile-time string argument",
+    ),
+    "compile_error_rejects_wrong_arity": (
+        "main proc() i16 { compile_error!()\nreturn 42 }",
+        b"", b"compile_error! requires one compile-time string argument",
+    ),
+    "type_execution_unreachable_is_selected_only": (
+        """
+        Storage proc(bad bool) type {
+            if (bad) unreachable
+            return i16
+        }
+        main proc() Storage(false) { return 42 }
+        """, b"42\n", None,
+    ),
+    "type_execution_unreachable_retains_source": (
+        """
+        Storage proc() type {
+            unreachable
+        }
+        main proc() Storage() { return 42 }
+        """, b"", b":2:5:",
+    ),
+    "rigid_slice_inference_preserves_borrowing_and_string_context": (
+        """
+        Box proc($T type) type { return struct { value T } }
+        length proc($T type, box @Box(T), value T) usize { return box.value.len + value.len }
+        main proc() [3]usize {
+            box Box([]u8) :: { value = "ab" }
+            bytes [3]mut u8 := [1, 2, 3]
+            return [length(&box, bytes[..]), length(&box, "abc"), length(&box, bytes)]
+        }
+        """, b"[5, 5, 5]\n", None,
+    ),
+    "rigid_slice_inference_rejects_readonly_weakening_reversal": (
+        """
+        Box proc($T type) type { return struct { value T } }
+        write proc($T type, box @Box(T), value T) void { value[0] = 0 }
+        main proc() i16 {
+            bytes [1]mut u8 := [42]
+            box Box([]mut u8) :: { value = bytes[..] }
+            readonly []u8 :: bytes[..]
+            write(&box, readonly)
+            return 42
+        }
+        """, b"", b"",
+    ),
+    "rigid_slice_inference_rejects_incompatible_elements": (
+        """
+        Box proc($T type) type { return struct { value T } }
+        length proc($T type, box @Box(T), value T) usize { return value.len }
+        main proc() usize {
+            box Box([]u8) :: { value = "" }
+            words [1]i16 :: [42]
+            return length(&box, words[..])
+        }
+        """, b"", b"",
+    ),
 }
 
 # Keep malformed schemas grouped: each must fail before generated storage is used.
@@ -9300,6 +9507,315 @@ def check_typeinfo_packages(temporary, executable):
     return len(cases) + 4
 
 
+def check_hashmap_packages(temporary, executable):
+    project = temporary / "hashmap"
+    project.mkdir()
+    (project / "build.hon").write_text("# project root\n")
+    for package in ("std", "ffi"):
+        (project / package).symlink_to(ROOT / package, target_is_directory=True)
+    source = project / "main.hon"
+    # Each growth allocation has distinct typed storage: clearing new entries
+    # must not overwrite the old entries before the library rehashes them.
+    source.write_text(textwrap.dedent("""
+        import "@std/hashmap"
+        import "@std/mem"
+        Value :: struct { number i16, items [2]mut i16 }
+        Slot :: alias hashmap.Entry(i16, Value)
+        StringSlot :: alias hashmap.Entry([]u8, Value)
+        State :: struct {
+            small *mut Slot
+            medium *mut Slot
+            large *mut Slot
+            strings *mut StringSlot
+            fail bool = false
+            allocations usize = 0
+            releases usize = 0
+        }
+        allocate proc(context ?@mut anyopaque, size usize, alignment usize) ?*mut u8 {
+            state @mut State :: ptrcast!(context?)
+            state.allocations += 1
+            if (state.fail or alignment != alignof!(Slot)) return null
+            if (size == sizeof!([8]Slot)) return ptrcast!(state.small)
+            if (size == sizeof!([16]Slot)) return ptrcast!(state.medium)
+            if (size == sizeof!([32]Slot)) return ptrcast!(state.large)
+            if (size == sizeof!([8]StringSlot)) return ptrcast!(state.strings)
+            return null
+        }
+        resize proc(
+            _ ?@mut anyopaque, _ ?*mut u8, _ usize, _ usize, _ usize,
+        ) ?*mut u8 { return null }
+        release proc(context ?@mut anyopaque, _ ?*mut u8, _ usize, _ usize) void {
+            state @mut State :: ptrcast!(context?)
+            state.releases += 1
+        }
+        table mem.AllocatorVTable :: { alloc = allocate, realloc = resize, free = release }
+        collision_hash proc(key i16) usize { return if (key == 0) 0 else 1 }
+        equivalent proc(left, right i16) bool {
+            return left - divtrunc!(left, 100) * 100 == right - divtrunc!(right, 100) * 100
+        }
+        exercise proc(allocator mem.Allocator, state @mut State) i16 ! (hashmap.PutError | mem.AllocError) {
+            map := hashmap.init(i16, Value, collision_hash, equivalent, allocator)
+            defer hashmap.deinit(&map)
+            if (map.count != 0 or map.entries.len != 0 or state.allocations != 0) return -1
+            if (hashmap.get(&map, 0) != null) return -2
+            original Value := { number = 0, items = [0, 1] }
+            try hashmap.put(&map, 0, original)
+            original.items[0] = 99
+            if (hashmap.get(&map, 0)?.items[0] != 0) return -3
+            copy := hashmap.get(&map, 0)?
+            copy.items[1] = 99
+            if (hashmap.get(&map, 100)?.items[1] != 1) return -4
+            duplicate := false
+            hashmap.put(&map, 100, Value{ number = 999, items = [9, 9] }) catch |err| {
+                duplicate = err == .key_exists
+            }
+            if (!duplicate or map.count != 1 or hashmap.get(&map, 0)?.number != 0) return -7
+            for (i16(1)..i16(12)) |key| {
+                try hashmap.put(&map, key, Value{ number = key * 2, items = [key, key + 1] })
+            }
+            if (map.count != 12 or map.entries.len != 16) return -5
+            if (state.allocations != 2 or state.releases != 1) return -6
+            state.fail = true
+            previous :: map.entries.ptr
+            calls :: state.allocations
+            released :: state.releases
+            failed := false
+            hashmap.put(&map, 12, original) catch |err| { failed = err == .out_of_memory }
+            if (!failed or map.count != 12 or map.entries.len != 16 or map.entries.ptr != previous) return -8
+            if (state.allocations != calls + 1 or state.releases != released) return -9
+            if (hashmap.get(&map, 12) != null or hashmap.get(&map, 111)?.number != 22) return -10
+            state.fail = false
+            for (i16(12)..i16(24)) |key| {
+                try hashmap.put(&map, key, Value{ number = key * 2, items = [key, key + 1] })
+            }
+            if (map.count != 24 or map.entries.len != 32) return -11
+            for (i16(0)..i16(24)) |key| {
+                value :: hashmap.get(&map, key + 100)?
+                if (value.number != key * 2 or value.items[0] != key or value.items[1] != key + 1) return -12
+            }
+            for map.entries |entry| {
+                if (entry.hash != 0 and entry.hash != 1) return -13
+            }
+            if (hashmap.get(&map, 99) != null) return -14
+            failed = false
+            hashmap.put(&map, 24, original) catch |err| { failed = err == .out_of_memory }
+            if (!failed or map.count != 24 or map.entries.len != 32) return -15
+            if (hashmap.get(&map, 23)?.number != 46 or hashmap.get(&map, 24) != null) return -16
+            return 42
+        }
+        exercise_automatic_and_string_keys proc(allocator mem.Allocator) i16 ! (hashmap.PutError | mem.AllocError) {
+            automatic := hashmap.init(i16, Value, null, null, allocator)
+            defer hashmap.deinit(&automatic)
+            for (i16(0)..i16(12)) |key| {
+                try hashmap.put(&automatic, key, Value{ number = key, items = [key, key + 1] })
+            }
+            edge Value :: { number = 42, items = [19, 23] }
+            try hashmap.put(&automatic, minval!(i16), edge)
+            try hashmap.put(&automatic, maxval!(i16), edge)
+            for (i16(0)..i16(12)) |key| {
+                value :: hashmap.get(&automatic, key)?
+                if (value.number != key or value.items[1] != key + 1) return -20
+            }
+            if (hashmap.get(&automatic, minval!(i16))?.number != 42
+                or hashmap.get(&automatic, maxval!(i16))?.items[0] != 19) return -21
+            if (hashmap.get(&automatic, -1) != null) return -22
+            strings hashmap.StringHashMap(Value) := { entries = &[], count = 0, allocator = allocator }
+            defer hashmap.deinit(&strings)
+            left [3]mut u8 := [97, 0, 98]
+            right [3]mut u8 := [97, 0, 98]
+            try hashmap.put(&strings, left[..], edge)
+            if (hashmap.get(&strings, right[..])?.items[1] != 23) return -23
+            duplicate := false
+            hashmap.put(&strings, right[..], Value{ number = 0, items = [0, 0] }) catch |err| {
+                duplicate = err == .key_exists
+            }
+            if (!duplicate or strings.count != 1 or hashmap.get(&strings, left[..])?.number != 42) return -24
+            try hashmap.put(&strings, "", edge)
+            if (hashmap.get(&strings, right[..2]) != null or hashmap.get(&strings, "")?.number != 42) return -25
+            return 42
+        }
+        main proc() i16 ! (hashmap.PutError | mem.AllocError) {
+            small [8]mut Slot := undefined
+            medium [16]mut Slot := undefined
+            large [32]mut Slot := undefined
+            string_storage [8]mut StringSlot := undefined
+            state State := {
+                small = (&small).ptr, medium = (&medium).ptr, large = (&large).ptr,
+                strings = (&string_storage).ptr,
+            }
+            allocator mem.Allocator :: { context = &state, vtable = &table }
+            result :: try exercise(allocator, &state)
+            if (result != 42) return result
+            if (state.allocations != 5 or state.releases != 3) return -17
+            state.fail = true
+            empty := hashmap.init(i16, Value, collision_hash, equivalent, allocator)
+            defer hashmap.deinit(&empty)
+            failed := false
+            hashmap.put(&empty, 0, Value{ number = 42, items = [4, 2] }) catch |err| {
+                failed = err == .out_of_memory
+            }
+            if (!failed or empty.count != 0 or empty.entries.len != 0) return -18
+            if (hashmap.get(&empty, 0) != null or state.allocations != 6 or state.releases != 3) return -19
+            state.fail = false
+            automatic_result :: try exercise_automatic_and_string_keys(allocator)
+            if (automatic_result != 42) return automatic_result
+            if (state.allocations != 10 or state.releases != 7) return -26
+            return 42
+        }
+    """).strip() + "\n")
+    check(source, executable, (b"42\n", None))
+    native_cases = (
+        """
+        import "@std/hashmap"
+        import "@std/mem"
+        Sparse :: enum(i16) { negative = -7, first = 3, far = 90 }
+        SparseAlias :: alias Sparse
+        Inner :: distinct u64
+        Id :: distinct Inner
+        integer_keys proc($K type) bool ! (hashmap.PutError | mem.AllocError) {
+            map hashmap.AutoHashMap(K, usize) := hashmap.init(K, usize, null, null, mem.c_allocator)
+            defer hashmap.deinit(&map)
+            keys [4]K :: [minval!(K), maxval!(K), K(1), K(2)]
+            for keys |key, index| { try hashmap.put(&map, key, index) }
+            for (3..40) |number| { try hashmap.put(&map, K(number), usize(number)) }
+            if (map.count != 41 or map.entries.len != 64) return false
+            for keys |key, index| { if (hashmap.get(&map, key)? != index) return false }
+            for (3..40) |number| {
+                if (hashmap.get(&map, K(number))? != usize(number)) return false
+            }
+            if (hashmap.get(&map, K(40)) != null) return false
+            if $(minval!(K) < 0) {
+                try hashmap.put(&map, K(-1), 99)
+                if (hashmap.get(&map, K(-1))? != 99) return false
+            }
+            duplicate := false
+            hashmap.put(&map, maxval!(K), 999) catch |err| { duplicate = err == .key_exists }
+            return duplicate and hashmap.get(&map, maxval!(K))? == 1
+        }
+        main proc() i16 ! (hashmap.PutError | mem.AllocError) {
+            if (!try integer_keys(i8) or !try integer_keys(u8)) return -1
+            if (!try integer_keys(i16) or !try integer_keys(u16)) return -2
+            if (!try integer_keys(i32) or !try integer_keys(u32)) return -3
+            if (!try integer_keys(i64) or !try integer_keys(u64)) return -4
+            if (!try integer_keys(isize) or !try integer_keys(usize)) return -5
+            flags hashmap.AutoHashMap(bool, i16) := hashmap.init(bool, i16, null, null, mem.c_allocator)
+            defer hashmap.deinit(&flags)
+            try hashmap.put(&flags, false, 19)
+            try hashmap.put(&flags, true, 23)
+            if (flags.count != 2 or hashmap.get(&flags, false)? != 19 or hashmap.get(&flags, true)? != 23) return -6
+            duplicate := false
+            hashmap.put(&flags, false, 99) catch |err| { duplicate = err == .key_exists }
+            if (!duplicate or flags.count != 2 or hashmap.get(&flags, false)? != 19) return -7
+            sparse hashmap.AutoHashMap(SparseAlias, i16) := hashmap.init(SparseAlias, i16, null, null, mem.c_allocator)
+            defer hashmap.deinit(&sparse)
+            try hashmap.put(&sparse, .negative, 7)
+            try hashmap.put(&sparse, .first, 3)
+            try hashmap.put(&sparse, .far, 90)
+            if (sparse.count != 3 or hashmap.get(&sparse, Sparse.negative)? != 7) return -8
+            if (hashmap.get(&sparse, .first)? != 3 or hashmap.get(&sparse, .far)? != 90) return -9
+            ids hashmap.AutoHashMap(Id, i16) := hashmap.init(Id, i16, null, null, mem.c_allocator)
+            defer hashmap.deinit(&ids)
+            try hashmap.put(&ids, Id(Inner(0)), 19)
+            try hashmap.put(&ids, Id(Inner(maxval!(u64))), 23)
+            if (hashmap.get(&ids, Id(Inner(0)))? != 19) return -10
+            if (hashmap.get(&ids, Id(Inner(maxval!(u64))))? != 23) return -11
+            if (hashmap.get(&ids, Id(Inner(1))) != null) return -12
+            return 42
+        }
+        """,
+        """
+        import "@std/hashmap"
+        import "@std/mem"
+        Padding :: struct_type!(.c, ["tag", "number"], [u8, u64], [null, null])
+        Row :: struct { values [2]u16 }
+        Key :: struct { padded Padding, rows [2]Row }
+        custom_hash proc(_ u16) usize { return 0 }
+        custom_eql proc(left, right u16) bool {
+            return left - divtrunc!(left, 100) * 100 == right - divtrunc!(right, 100) * 100
+        }
+        main proc() i16 ! (hashmap.PutError | mem.AllocError) {
+            # The alias supplies the library's private string callbacks.
+            strings hashmap.StringHashMap(i16) := { entries = &[], count = 0, allocator = mem.c_allocator }
+            defer hashmap.deinit(&strings)
+            left [3]mut u8 := [97, 0, 98]
+            right [3]mut u8 := [97, 0, 98]
+            other [3]mut u8 := [97, 0, 99]
+            if ((&left).ptr == (&right).ptr) return -7
+            try hashmap.put(&strings, left[..], 42)
+            records hashmap.AutoHashMap(Key, i16) := hashmap.init(Key, i16, null, null, mem.c_allocator)
+            defer hashmap.deinit(&records)
+            first Key := { padded = { tag = 7, number = maxval!(u64) }, rows = [{ values = [2, 9] }, { values = [4, 8] }] }
+            same Key := { padded = { tag = 7, number = maxval!(u64) }, rows = [{ values = [2, 9] }, { values = [4, 8] }] }
+            first_bytes *mut u8 :: ptrcast!(&first.padded)
+            same_bytes *mut u8 :: ptrcast!(&same.padded)
+            if (sizeof!(Padding) != 16 or alignof!(Padding) != 8) return -1
+            for (usize(1)..usize(8)) |index| {
+                first_bytes[index] = 17
+                same_bytes[index] = 238
+            }
+            if (first_bytes[1] == same_bytes[1]) return -2
+            try hashmap.put(&records, first, 19)
+            if (hashmap.get(&records, same)? != 19) return -3
+            duplicate := false
+            hashmap.put(&records, same, 99) catch |err| { duplicate = err == .key_exists }
+            if (!duplicate or records.count != 1 or hashmap.get(&records, first)? != 19) return -4
+            reversed :: Key{ padded = { tag = 7, number = maxval!(u64) }, rows = [{ values = [9, 2] }, { values = [4, 8] }] }
+            swapped :: Key{ padded = { tag = 7, number = maxval!(u64) }, rows = [{ values = [4, 8] }, { values = [2, 9] }] }
+            try hashmap.put(&records, reversed, 23)
+            try hashmap.put(&records, swapped, 31)
+            if (hashmap.get(&records, reversed)? != 23 or hashmap.get(&records, swapped)? != 31) return -5
+            same.padded.number = 0
+            if (hashmap.get(&records, same) != null or records.count != 3) return -6
+            if (hashmap.get(&strings, right[..])? != 42) return -8
+            if (hashmap.get(&strings, right[..2]) != null or hashmap.get(&strings, other[..]) != null) return -9
+            duplicate = false
+            hashmap.put(&strings, right[..], 99) catch |err| { duplicate = err == .key_exists }
+            if (!duplicate or strings.count != 1 or hashmap.get(&strings, left[..])? != 42) return -10
+            try hashmap.put(&strings, "", 7)
+            try hashmap.put(&strings, other[..], 23)
+            if (strings.count != 3 or hashmap.get(&strings, "")? != 7 or hashmap.get(&strings, other[..])? != 23) return -11
+            custom := hashmap.init(u16, i16, custom_hash, custom_eql, mem.c_allocator)
+            defer hashmap.deinit(&custom)
+            for (u16(1)..u16(20)) |key| { try hashmap.put(&custom, key, i16(key * 2)) }
+            for (u16(1)..u16(20)) |key| {
+                if (hashmap.get(&custom, key + 100)? != i16(key * 2)) return -12
+            }
+            duplicate = false
+            hashmap.put(&custom, 101, 999) catch |err| { duplicate = err == .key_exists }
+            if (!duplicate or custom.count != 19 or hashmap.get(&custom, 1)? != 2) return -13
+            if (hashmap.get(&custom, 99) != null) return -14
+            return 42
+        }
+        """,
+    )
+    for text in native_cases:
+        source.write_text(textwrap.dedent(text).strip() + "\n")
+        interpreted = run(str(HONEY), "run", str(source))
+        assert interpreted.returncode == 1 and interpreted.stdout == b"", outcome(interpreted)
+        assert b"foreign function calls are unsupported by the interpreter" in interpreted.stderr, outcome(interpreted)
+        assert len(interpreted.stderr.splitlines()) == 1, outcome(interpreted)
+        for optimization in ("-O0", "-O2"):
+            built = run(str(HONEY), "build", str(source), "-o", str(executable), optimization)
+            assert outcome(built) == (0, b"", b""), outcome(built)
+            assert outcome(run(str(executable))) == (0, b"42\n", b""), optimization
+            executable.unlink()
+    invalid_keys = (("f64", "f64(1)"), ("[]u8", '"abc"'), ("?i16", "some!(i16(1))"))
+    for key_type, key in invalid_keys:
+        source.write_text(textwrap.dedent(f"""
+            import "@std/hashmap"
+            import "@std/mem"
+            main proc() bool {{
+                map := hashmap.init({key_type}, i16, null, null, mem.c_allocator)
+                return hashmap.get(&map, {key}) == null
+            }}
+        """).strip() + "\n")
+        check(source, executable, (
+            b"true\n",
+            b"AutoHashMap key requires integers, booleans, enums, distinct types, arrays or records",
+        ))
+    return 1 + len(invalid_keys), len(native_cases)
+
+
 def main():
     with tempfile.TemporaryDirectory(prefix="honey native ' ; $") as directory:
         temporary = Path(directory)
@@ -9316,6 +9832,8 @@ def main():
         allocator_count = check_allocator_libc(temporary, executable)
         arraylist_count, arraylist_native_count = check_arraylist_packages(temporary, executable)
         count += arraylist_count
+        hashmap_count, hashmap_native_count = check_hashmap_packages(temporary, executable)
+        count += hashmap_count
         count += check_packages(temporary, executable)
         count += check_namespace_packages(temporary, executable)
         count += check_record_packages(temporary, executable)
@@ -9342,7 +9860,7 @@ def main():
         assert not executable.exists()
         invalid = run(str(HONEY), "build", str(source), "-o", str(executable), "-O3")
         assert invalid.returncode == 2 and b"usage:" in invalid.stderr, outcome(invalid)
-        print(f"{count} programs matched interpreter at -O0 and -O2; {allocator_count + arraylist_native_count} native allocator programs, LLVM output and CLI errors passed")
+        print(f"{count} programs matched interpreter at -O0 and -O2; {allocator_count + arraylist_native_count + hashmap_native_count} native allocator programs, LLVM output and CLI errors passed")
 
 
 if __name__ == "__main__":