Add int::MIN/MAX, Vec struct inference, and fix for-loop/Vec push codegen for non-primitive elements.

Author: Cod-e-Codes

.cursor/skills/ion-lsp-vscode/SKILL.md

@@ -68,7 +68,7 @@ Adjust path for OS (no `.exe` on Linux/macOS).
 3. **Type-check** - `tc::TypeChecker::check_program_collecting_with_source` on merged program, symbols seeded from buffer AST (`check_program_collecting` for unit tests)
 4. Publish diagnostics from lexer, parser, import resolution, or type-check errors
 5. **Hover** - expression types, symbol docs, builtin signatures
-6. **Completion** - prefix-filtered; context-aware for `alias::` and `Type.` / `expr.`
+6. **Completion** - prefix-filtered; context-aware for `alias::` and `Type.` / `expr.` (`int`, `i8`-`i64`, `u8`-`u64`, `uint` expose `MIN`/`MAX` via `BUILTIN_TYPE_MEMBERS` in `util.rs`)
 7. **Go to definition** - variables, calls, methods, fields, variants, type aliases; cross-file via `module_paths`
 8. **References**, **document symbols**, **signature help**, **semantic tokens**
 9. **`did_change_watched_files`** - re-check open files whose import dependencies changed

.cursor/skills/writing-ion-code/SKILL.md

@@ -65,6 +65,14 @@ Import paths like `import "stdlib/io.ion" as io;` resolve via stdlib search path
 ```ion
 let x: int = 10;
 let mut v: Vec<int> = Vec::new();
+let items: Vec<MyStruct> = Vec::new(); // element type from annotation
+```
+
+**Integer limits**
+
+```ion
+if n == int::MIN { ... }
+let cap: int = int::MAX;
 ```
 
 **Structs and enums**

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, and portable Git Bash paths for `test_runner.sh`.
-- **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). 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`. 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). 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`.
 - **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

@@ -488,6 +488,8 @@ Ion includes the following primitive types:
 - Boolean: `bool`
 - Unit / void: `void` (function return type with no value)
 
+Each integer primitive exposes compile-time limits as `Type::MIN` and `Type::MAX` (for example `int::MIN`, `i32::MAX`, `u8::MIN`). These lower to C-safe literals (avoiding `-2147483648`-style unary overflow in generated C).
+
 Additional built-in generic types:
 
 - `Box<T>` – heap-allocated `T` with owning semantics (`Box::new()`, `Box::unwrap()`)

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) {
@@ -242,6 +242,73 @@ 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);
@@ -296,7 +363,7 @@ void io_print_int(int ION_MAYBE_UNUSED n) {
     }
     if (value < 0) {
         negative = 1;
-        if (value == (-2147483648)) {
+        if (value == (0 - 2147483647 - 1)) {
             {
                 int _result = write(1, (uint8_t*)"-2147483648", 11);
                 (void)_result;
@@ -316,8 +383,8 @@ void io_print_int(int ION_MAYBE_UNUSED n) {
     }
     int i = 0;
     while (i < (len / 2)) {
-        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]); });
+        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]); });
         buf[((len - 1) - i)] = tmp;
         i = (i + 1);
     }
@@ -336,73 +403,6 @@ 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 == (-2147483648)) {
-            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/hello_world_safe.c

@@ -83,7 +83,7 @@ void io_print_int(int ION_MAYBE_UNUSED n) {
     }
     if (value < 0) {
         negative = 1;
-        if (value == (-2147483648)) {
+        if (value == (0 - 2147483647 - 1)) {
             {
                 int _result = write(1, (uint8_t*)"-2147483648", 11);
                 (void)_result;