Fix tuple Vec codegen and defer struct field nulls after call moves; add todo_demo.

Resolve tuple element types in IR, mangle tuple_Vec_T names with compound-zero returns, flush owned field neutralization at statement boundaries, and add todo_demo plus integration tests.

Author: Cod-e-Codes

.cursor/skills/finding-ion-bugs/references/bug-hotspots.md

@@ -13,7 +13,7 @@ CLI errors use `TypeCheckError` Debug form (`UseAfterMove { ... }`). LSP reforma
 ## Codegen (`src/cgen/`)
 
 - Drop order and `ion_drop_*` for moved fields
-- **Struct field move-out**: owned fields null after partial move (`board.items = NULL`; `struct_field_move_neutralizes_source_field`)
+- **Struct field move-out**: owned fields null after partial move on the next statement (`board.items = NULL`; deferred when the move is a call argument)
 - **Vec::push lvalues**: struct variables and field paths use `&item`, not compound literal (`vec_push_struct_var_uses_address_of_lvalue`)
 - **Enum emission order**: non-generic enums before structs in single-file C output
 - **Tuple mangle**: `tuple_type_name` sanitizes `*` and brackets when names include `Vec` types

CHANGELOG.md

@@ -9,7 +9,7 @@
 - **LSP**: diagnostics, hover, completion, go-to-definition; multi-error reporting; symbol table mirroring; diagnostics cleared on close; hover fixes for `let` bindings and module-qualified calls. Contiguous `//` doc comments attached to declarations (including `pub` items) for hover.
 - **Tooling**: GitHub Actions CI (Linux and Windows), pinned toolchain (1.96.0), `test_expectations.tsv` manifest, `--version`, line-numbered errors, Cursor agent skills. Split `tc` and `cgen` into submodules. `ion-build` driver and `ion.toml` manifests (`single`/`multi`, `out_dir`, `cflags`, `ldflags`, `stdlib_paths`, `emit_in_source`); per-example manifests and `build_hello`/`build_bad_main` harness smoke tests. Shared `discover_import_config` and stdlib search paths for `ion-compiler`, `ion-build`, and LSP. Integration harness precompiles `runtime/ion_runtime.c` once per run (`RUNTIME_OBJ`). `writing-ion-code` agent skill; `creating-ion-skills` examples index lists all eight project skills. Documented checked-in `examples/*.c` codegen snapshots in README and integration-test skill; regenerated example C output. Fixed `researching-pl-literature` skill `paper-seeds` reference formatting.
 - **Docs**: README, CONTRIBUTING, ION_SPEC, and agent skills aligned on project layout, `ion-build` workflow, `emit_in_source`, stdlib import order, LSP features and limitations, `src/build/` checklists, portable Git Bash paths for `test_runner.sh`, and rebuilding release binaries before harness or example C regen (stale `target/release/ion-compiler` note).
-- **Fixes**: match rvalue codegen, `Vec` struct drops, channel codegen, parser handling of `alias::call()`, scope-drop for moved-into-call bindings, HTTP server on Windows, integration harness on Windows. Cgen return-unwind: stop marking bindings dropped after inner-branch `return` (restores outer-path drops), dedupe `_`-prefixed unused silences, mark call arguments moved at emission to avoid double-free on unwind, and unify all function returns via `emit_function_return` (including diverging rvalue `match` arms). Cgen struct field move-out neutralizes owned fields after partial move (e.g. `board.items`); `Vec::push` passes address of struct lvalues; non-generic enums emit before structs; tuple type mangling strips `*` for `Vec`-containing names. Integer indexing and `Vec<i32>` inference in the type checker. Match rvalue arms: reject diverging arms mixed with value arms; structural control-flow analysis for arm bodies (nested `if`/`else`, `loop` without `break`, `unsafe` blocks); reject mixed diverge and value-producing paths within one arm; cgen assigns through `if`/`else` value branches. `fmt::int_to_string` uses `String::push_byte` per digit instead of per-digit `push_str` branches; integration test asserts `0`, negatives, and `int::MIN`. `int::MIN`/`int::MAX` on integer primitives; `Vec::new()`/`with_capacity()` infer `T` from a `let` type annotation. Clippy fix in `portable_source_label`.
+- **Fixes**: match rvalue codegen, `Vec` struct drops, channel codegen, parser handling of `alias::call()`, scope-drop for moved-into-call bindings, HTTP server on Windows, integration harness on Windows. Cgen return-unwind: stop marking bindings dropped after inner-branch `return` (restores outer-path drops), dedupe `_`-prefixed unused silences, mark call arguments moved at emission to avoid double-free on unwind, and unify all function returns via `emit_function_return` (including diverging rvalue `match` arms). Cgen struct field move-out neutralizes owned fields after partial move, deferred to statement end when the move is a call argument; `Vec::push` passes address of struct lvalues; non-generic enums emit before structs; tuple IR uses resolved element types and `tuple_Vec_T` mangling with compound-zero `ret_val` for tuple returns. Integer indexing and `Vec<i32>` inference in the type checker. Match rvalue arms: reject diverging arms mixed with value arms; structural control-flow analysis for arm bodies (nested `if`/`else`, `loop` without `break`, `unsafe` blocks); reject mixed diverge and value-producing paths within one arm; cgen assigns through `if`/`else` value branches. `fmt::int_to_string` uses `String::push_byte` per digit instead of per-digit `push_str` branches; integration test asserts `0`, negatives, and `int::MIN`. `int::MIN`/`int::MAX` on integer primitives; `Vec::new()`/`with_capacity()` infer `T` from a `let` type annotation. Clippy fix in `portable_source_label`.
 - **Examples**: `text_summary` (fixture file), `data_lib` (multi-module), `channel_worker` (flat single-file). Per-example `*.toml` manifests for `ion-build`. `http_server` accepts one client then exits (verifiable demo).
 - **Multi-file fixes**: merge private struct types for cross-module type checking; per-module C symbol prefixes in multi-file codegen (`io_print_int`); walk-up `runtime/` discovery for nested build directories. Integration tests `test_multi_struct`, `test_multi_fmt_io`. Example policy: single-file examples commit `.c` snapshots; `data_lib` multi-file keeps `.ion` only.
 

ION_SPEC.md

@@ -1258,7 +1258,7 @@ stronger contract.
 - LSP go-to-definition for built-in methods (`Vec::push`, `String::len`, etc.) has no target (signature hover only)
 - LSP go-to-definition for type names in type annotations (no source spans on `Type` AST nodes)
 - Function types: capture-free fn literals implemented; no capturing closures, no generic `fn(T) -> R` type parameters, no method values as fn pointers
-- Tuple values: no nested tuples, `==` on tuples, struct fields holding tuples, or generic `(T1, T2)` parameters
+- Tuple values: no nested tuples, `==` on tuples, struct fields holding tuples, or generic `(T1, T2)` parameters. Flat tuples may hold owned heap types (for example `(Vec<T>, int)`).
 
 ### 11. Future Work (Non-Normative)
 

examples/access_log.c

@@ -53,13 +53,13 @@ int parse_line_at(int ION_MAYBE_UNUSED index);
 int scan_logs(ion_sender_t ION_MAYBE_UNUSED code_tx, int ION_MAYBE_UNUSED expected);
 int valid_log_count(void);
 int main(void);
-void fmt_print_int(int ION_MAYBE_UNUSED n);
-void fmt_println_int(int ION_MAYBE_UNUSED n);
-ion_string_t* fmt_int_to_string(int ION_MAYBE_UNUSED n);
 void io_print(ion_string_t* ION_MAYBE_UNUSED s);
 void io_println(ion_string_t* ION_MAYBE_UNUSED s);
 void io_print_str(uint8_t* ION_MAYBE_UNUSED s, int ION_MAYBE_UNUSED len);
 void io_print_int(int ION_MAYBE_UNUSED n);
+void fmt_print_int(int ION_MAYBE_UNUSED n);
+void fmt_println_int(int ION_MAYBE_UNUSED n);
+ion_string_t* fmt_int_to_string(int ION_MAYBE_UNUSED n);
 ion_string_t* line_at(int ION_MAYBE_UNUSED index) {
     ion_string_t* ret_val = 0;
     if (index == 0) {
@@ -242,73 +242,6 @@ int main(void) {
         return ret_val;
 }
 
-void fmt_print_int(int ION_MAYBE_UNUSED n) {
-    io_print_int(n);
-    goto epilogue;
-epilogue:
-        return;
-}
-
-void fmt_println_int(int ION_MAYBE_UNUSED n) {
-    io_print_int(n);
-    {
-        int _newline = write(1, (uint8_t*)"\n", 1);
-        (void)_newline;
-    }
-    goto epilogue;
-epilogue:
-        return;
-}
-
-ion_string_t* fmt_int_to_string(int ION_MAYBE_UNUSED n) {
-    ion_string_t* ret_val = 0;
-    uint8_t buf[12] = {0};
-    int len = 0;
-    int negative = 0;
-    int value = n;
-    ion_string_t* result = ion_string_new();
-    if (value == 0) {
-        ret_val = ion_string_from_literal("0", 1);
-        (void)result;
-        (void)negative;
-        (void)len;
-        (void)buf;
-        if (result) { ion_string_free(result); }
-        goto epilogue;
-    }
-    if (value < 0) {
-        negative = 1;
-        if (value == (0 - 2147483647 - 1)) {
-            ret_val = ion_string_from_literal("-2147483648", 11);
-            (void)result;
-            (void)negative;
-            (void)len;
-            (void)buf;
-            if (result) { ion_string_free(result); }
-            goto epilogue;
-        }
-        value = (0 - value);
-    }
-    while (value > 0) {
-        int digit = (value % 10);
-        buf[len] = (uint8_t)(48 + digit);
-        len = (len + 1);
-        value = (value / 10);
-    }
-    if (negative) {
-        ion_string_push_byte(result, (unsigned char)((uint8_t)45));
-    }
-    int i = (len - 1);
-    while (i >= 0) {
-        ion_string_push_byte(result, (unsigned char)(({ int __ion_idx_2 = i; (__ion_idx_2 >= 0 && __ion_idx_2 < 12) ? buf[__ion_idx_2] : (ion_panic("Array index out of bounds"), buf[0]); })));
-        i = (i - 1);
-    }
-    ret_val = result;
-    goto epilogue;
-epilogue:
-        return ret_val;
-}
-
 void io_print(ion_string_t* ION_MAYBE_UNUSED s) {
     {
         int _result = write(1, s->data, (int)s->len);
@@ -383,8 +316,8 @@ void io_print_int(int ION_MAYBE_UNUSED n) {
     }
     int i = 0;
     while (i < (len / 2)) {
-        uint8_t tmp = ({ int __ion_idx_3 = i; (__ion_idx_3 >= 0 && __ion_idx_3 < 12) ? buf[__ion_idx_3] : (ion_panic("Array index out of bounds"), buf[0]); });
-        buf[i] = ({ int __ion_idx_4 = ((len - 1) - i); (__ion_idx_4 >= 0 && __ion_idx_4 < 12) ? buf[__ion_idx_4] : (ion_panic("Array index out of bounds"), buf[0]); });
+        uint8_t tmp = ({ int __ion_idx_2 = i; (__ion_idx_2 >= 0 && __ion_idx_2 < 12) ? buf[__ion_idx_2] : (ion_panic("Array index out of bounds"), buf[0]); });
+        buf[i] = ({ int __ion_idx_3 = ((len - 1) - i); (__ion_idx_3 >= 0 && __ion_idx_3 < 12) ? buf[__ion_idx_3] : (ion_panic("Array index out of bounds"), buf[0]); });
         buf[((len - 1) - i)] = tmp;
         i = (i + 1);
     }
@@ -403,6 +336,73 @@ void io_print_int(int ION_MAYBE_UNUSED n) {
         return;
 }
 
+void fmt_print_int(int ION_MAYBE_UNUSED n) {
+    io_print_int(n);
+    goto epilogue;
+epilogue:
+        return;
+}
+
+void fmt_println_int(int ION_MAYBE_UNUSED n) {
+    io_print_int(n);
+    {
+        int _newline = write(1, (uint8_t*)"\n", 1);
+        (void)_newline;
+    }
+    goto epilogue;
+epilogue:
+        return;
+}
+
+ion_string_t* fmt_int_to_string(int ION_MAYBE_UNUSED n) {
+    ion_string_t* ret_val = 0;
+    uint8_t buf[12] = {0};
+    int len = 0;
+    int negative = 0;
+    int value = n;
+    ion_string_t* result = ion_string_new();
+    if (value == 0) {
+        ret_val = ion_string_from_literal("0", 1);
+        (void)result;
+        (void)negative;
+        (void)len;
+        (void)buf;
+        if (result) { ion_string_free(result); }
+        goto epilogue;
+    }
+    if (value < 0) {
+        negative = 1;
+        if (value == (0 - 2147483647 - 1)) {
+            ret_val = ion_string_from_literal("-2147483648", 11);
+            (void)result;
+            (void)negative;
+            (void)len;
+            (void)buf;
+            if (result) { ion_string_free(result); }
+            goto epilogue;
+        }
+        value = (0 - value);
+    }
+    while (value > 0) {
+        int digit = (value % 10);
+        buf[len] = (uint8_t)(48 + digit);
+        len = (len + 1);
+        value = (value / 10);
+    }
+    if (negative) {
+        ion_string_push_byte(result, (unsigned char)((uint8_t)45));
+    }
+    int i = (len - 1);
+    while (i >= 0) {
+        ion_string_push_byte(result, (unsigned char)(({ int __ion_idx_4 = i; (__ion_idx_4 >= 0 && __ion_idx_4 < 12) ? buf[__ion_idx_4] : (ion_panic("Array index out of bounds"), buf[0]); })));
+        i = (i - 1);
+    }
+    ret_val = result;
+    goto epilogue;
+epilogue:
+        return ret_val;
+}
+
 
 static void* ion_spawn_entry_0(void* arg) {
     ion_spawn_ctx_0* ctx = (ion_spawn_ctx_0*)arg;

examples/text_summary/text_summary.c

@@ -40,22 +40,22 @@ typedef struct TextCounts {
     int words;
 } TextCounts;
 
+extern int write(int fd, uint8_t* buf, int count);
+
 extern int open(uint8_t* path, int flags);
 extern int read(int fd, uint8_t* buf, int count);
 extern int close(int fd);
 
-extern int write(int fd, uint8_t* buf, int count);
-
 TextCounts summarize_text(ion_string_t* ION_MAYBE_UNUSED text);
 int main(void);
-ReadResult fs_read_to_string_result(ion_string_t* ION_MAYBE_UNUSED path);
 void fmt_print_int(int ION_MAYBE_UNUSED n);
 void fmt_println_int(int ION_MAYBE_UNUSED n);
 ion_string_t* fmt_int_to_string(int ION_MAYBE_UNUSED n);
 void io_print(ion_string_t* ION_MAYBE_UNUSED s);
 void io_println(ion_string_t* ION_MAYBE_UNUSED s);
 void io_print_str(uint8_t* ION_MAYBE_UNUSED s, int ION_MAYBE_UNUSED len);
 void io_print_int(int ION_MAYBE_UNUSED n);
+ReadResult fs_read_to_string_result(ion_string_t* ION_MAYBE_UNUSED path);
 TextCounts summarize_text(ion_string_t* ION_MAYBE_UNUSED text) {
     TextCounts ret_val = {0};
     int lines = 0;
@@ -123,46 +123,6 @@ int main(void) {
         return ret_val;
 }
 
-ReadResult fs_read_to_string_result(ion_string_t* ION_MAYBE_UNUSED path) {
-    ReadResult ret_val = {0};
-    {
-        int fd = open(path->data, 0);
-        if (fd < 0) {
-            ret_val = ReadResult_Err_new((-1));
-            if (path) { ion_string_free(path); }
-            goto epilogue;
-        }
-        ion_string_t* text = ion_string_new();
-        uint8_t buf[256] = {0};
-        int n = read(fd, &buf[0], 256);
-        while (n > 0) {
-            int i = 0;
-            while (i < n) {
-                ion_string_push_byte(text, (unsigned char)(buf[i]));
-                i = (i + 1);
-            }
-            n = read(fd, &buf[0], 256);
-        }
-        if (n < 0) {
-            int _closed = close(fd);
-            (void)_closed;
-            ret_val = ReadResult_Err_new((-2));
-            if (text) { ion_string_free(text); }
-            if (path) { ion_string_free(path); }
-            goto epilogue;
-        }
-        int _closed = close(fd);
-        (void)_closed;
-        ret_val = ReadResult_Ok_new(text);
-        if (path) { ion_string_free(path); }
-        goto epilogue;
-    }
-    if (path) { ion_string_free(path); }
-    goto epilogue;
-epilogue:
-        return ret_val;
-}
-
 void fmt_print_int(int ION_MAYBE_UNUSED n) {
     io_print_int(n);
     goto epilogue;
@@ -324,3 +284,43 @@ void io_print_int(int ION_MAYBE_UNUSED n) {
         return;
 }
 
+ReadResult fs_read_to_string_result(ion_string_t* ION_MAYBE_UNUSED path) {
+    ReadResult ret_val = {0};
+    {
+        int fd = open(path->data, 0);
+        if (fd < 0) {
+            ret_val = ReadResult_Err_new((-1));
+            if (path) { ion_string_free(path); }
+            goto epilogue;
+        }
+        ion_string_t* text = ion_string_new();
+        uint8_t buf[256] = {0};
+        int n = read(fd, &buf[0], 256);
+        while (n > 0) {
+            int i = 0;
+            while (i < n) {
+                ion_string_push_byte(text, (unsigned char)(buf[i]));
+                i = (i + 1);
+            }
+            n = read(fd, &buf[0], 256);
+        }
+        if (n < 0) {
+            int _closed = close(fd);
+            (void)_closed;
+            ret_val = ReadResult_Err_new((-2));
+            if (text) { ion_string_free(text); }
+            if (path) { ion_string_free(path); }
+            goto epilogue;
+        }
+        int _closed = close(fd);
+        (void)_closed;
+        ret_val = ReadResult_Ok_new(text);
+        if (path) { ion_string_free(path); }
+        goto epilogue;
+    }
+    if (path) { ion_string_free(path); }
+    goto epilogue;
+epilogue:
+        return ret_val;
+}
+