Fix cgen return-unwind drops, dedupe _ silence, and mark call moves at emission.

Cod-e-Codes · Cod-e-Codes · commit 46621d1de1ee · 2026-06-25T19:46:12.000-04:00
Stop poisoning the scope stack after inner-branch returns, run fallthrough cleanup before goto epilogue, regenerate example C snapshots, and note the fix in CHANGELOG.
diff --git a/CHANGELOG.md b/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. 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, and mark call arguments moved at emission to avoid double-free on unwind. 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`.
 - **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.
 
diff --git a/examples/access_log.c b/examples/access_log.c
@@ -228,13 +228,15 @@ int main(void) {
     }
     if (auth_failures != 1) {
         ret_val = 2;
+        if (done_rx_mut.channel) { ion_channel_handle_drop(done_rx_mut.channel); }
         goto epilogue;
     }
     ion_string_t* server_line = fmt_int_to_string(server_errors);
     io_println(server_line);
     ion_string_t* auth_line = fmt_int_to_string(auth_failures);
     io_println(auth_line);
     ret_val = 0;
+    if (done_rx_mut.channel) { ion_channel_handle_drop(done_rx_mut.channel); }
     goto epilogue;
 epilogue:
         return ret_val;
@@ -244,11 +246,10 @@ void io_print(ion_string_t* ION_MAYBE_UNUSED s) {
     {
         int _result = write(1, s->data, (int)s->len);
         (void)_result;
-        (void)_result;
     }
+    if (s) { ion_string_free(s); }
     goto epilogue;
 epilogue:
-        if (s) { ion_string_free(s); }
         return;
 }
 
@@ -258,24 +259,20 @@ void io_println(ion_string_t* ION_MAYBE_UNUSED s) {
         (void)_result;
         int _newline = write(1, (uint8_t*)"\n", 1);
         (void)_newline;
-        (void)_newline;
-        (void)_result;
     }
+    if (s) { ion_string_free(s); }
     goto epilogue;
 epilogue:
-        if (s) { ion_string_free(s); }
         return;
 }
 
 void io_print_str(uint8_t* ION_MAYBE_UNUSED s, int ION_MAYBE_UNUSED len) {
     if (len < 0) {
-                (void)s;
-        goto epilogue;
+                goto epilogue;
     }
     {
         int _result = write(1, s, len);
         (void)_result;
-        (void)_result;
     }
     goto epilogue;
 epilogue:
@@ -291,7 +288,6 @@ void io_print_int(int ION_MAYBE_UNUSED n) {
         {
             int _result = write(1, (uint8_t*)"0", 1);
             (void)_result;
-            (void)_result;
         }
                 (void)negative;
         (void)len;
@@ -304,9 +300,11 @@ void io_print_int(int ION_MAYBE_UNUSED n) {
             {
                 int _result = write(1, (uint8_t*)"-2147483648", 11);
                 (void)_result;
-                (void)_result;
             }
-                        goto epilogue;
+                        (void)negative;
+            (void)len;
+            (void)buf;
+            goto epilogue;
         }
         value = (0 - value);
     }
@@ -327,13 +325,11 @@ void io_print_int(int ION_MAYBE_UNUSED n) {
         {
             int _minus = write(1, (uint8_t*)"-", 1);
             (void)_minus;
-            (void)_minus;
         }
     }
     {
         int _result = write(1, &buf[0], len);
         (void)_result;
-        (void)_result;
     }
     goto epilogue;
 epilogue:
@@ -352,7 +348,6 @@ void fmt_println_int(int ION_MAYBE_UNUSED n) {
     {
         int _newline = write(1, (uint8_t*)"\n", 1);
         (void)_newline;
-        (void)_newline;
     }
     goto epilogue;
 epilogue:
@@ -379,6 +374,11 @@ ion_string_t* fmt_int_to_string(int ION_MAYBE_UNUSED n) {
         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);
diff --git a/examples/channel_worker.c b/examples/channel_worker.c
@@ -65,6 +65,8 @@ int main(void) {
         goto epilogue;
     }
     ret_val = 0;
+    if (done_rx_mut.channel) { ion_channel_handle_drop(done_rx_mut.channel); }
+    if (job_tx.channel) { ion_channel_handle_drop(job_tx.channel); }
     goto epilogue;
 epilogue:
         return ret_val;
diff --git a/examples/hello_world.c b/examples/hello_world.c
@@ -21,7 +21,6 @@ int main(void) {
     {
         int _result = write(1, (uint8_t*)"Hello, World!\n", 14);
         (void)_result;
-        (void)_result;
     }
     ret_val = 0;
     goto epilogue;
diff --git a/examples/hello_world_safe.c b/examples/hello_world_safe.c
@@ -33,11 +33,10 @@ void io_print(ion_string_t* ION_MAYBE_UNUSED s) {
     {
         int _result = write(1, s->data, (int)s->len);
         (void)_result;
-        (void)_result;
     }
+    if (s) { ion_string_free(s); }
     goto epilogue;
 epilogue:
-        if (s) { ion_string_free(s); }
         return;
 }
 
@@ -47,24 +46,20 @@ void io_println(ion_string_t* ION_MAYBE_UNUSED s) {
         (void)_result;
         int _newline = write(1, (uint8_t*)"\n", 1);
         (void)_newline;
-        (void)_newline;
-        (void)_result;
     }
+    if (s) { ion_string_free(s); }
     goto epilogue;
 epilogue:
-        if (s) { ion_string_free(s); }
         return;
 }
 
 void io_print_str(uint8_t* ION_MAYBE_UNUSED s, int ION_MAYBE_UNUSED len) {
     if (len < 0) {
-                (void)s;
-        goto epilogue;
+                goto epilogue;
     }
     {
         int _result = write(1, s, len);
         (void)_result;
-        (void)_result;
     }
     goto epilogue;
 epilogue:
@@ -80,7 +75,6 @@ void io_print_int(int ION_MAYBE_UNUSED n) {
         {
             int _result = write(1, (uint8_t*)"0", 1);
             (void)_result;
-            (void)_result;
         }
                 (void)negative;
         (void)len;
@@ -93,9 +87,11 @@ void io_print_int(int ION_MAYBE_UNUSED n) {
             {
                 int _result = write(1, (uint8_t*)"-2147483648", 11);
                 (void)_result;
-                (void)_result;
             }
-                        goto epilogue;
+                        (void)negative;
+            (void)len;
+            (void)buf;
+            goto epilogue;
         }
         value = (0 - value);
     }
@@ -116,13 +112,11 @@ void io_print_int(int ION_MAYBE_UNUSED n) {
         {
             int _minus = write(1, (uint8_t*)"-", 1);
             (void)_minus;
-            (void)_minus;
         }
     }
     {
         int _result = write(1, &buf[0], len);
         (void)_result;
-        (void)_result;
     }
     goto epilogue;
 epilogue:
diff --git a/examples/http_server.c b/examples/http_server.c
@@ -73,12 +73,6 @@ int handle_client(int ION_MAYBE_UNUSED client_fd) {
         int _sent6 = send_sys(client_fd, (uint8_t*)"<html><head><title>Ion HTTP Server</title></head><body><h1>Hello from Ion!</h1><p>This is a simple HTTP server written in Ion.</p></body></html>", 89, 0);
         (void)_sent6;
         close(client_fd);
-        (void)_sent6;
-        (void)_sent5;
-        (void)_sent4;
-        (void)_sent3;
-        (void)_sent2;
-        (void)_sent1;
     }
     ret_val = 0;
     goto epilogue;
@@ -148,7 +142,6 @@ static void* ion_spawn_entry_0(void* arg) {
     free(ctx);
     int _result = handle_client(client_fd);
     (void)_result;
-    (void)_result;
     goto spawn_0_epilogue;
 spawn_0_epilogue:
     return NULL;
diff --git a/examples/showcase.c b/examples/showcase.c
@@ -249,6 +249,7 @@ int for_loop_example(void) {
         goto epilogue;
     }
     ret_val = 0;
+    if (__for_container_2197) { ion_vec_free((ion_vec_t*)(__for_container_2197)); }
     goto epilogue;
 epilogue:
         return ret_val;
@@ -384,7 +385,6 @@ int pattern_matching_example(void) {
             int _c = match_val_5.data.variant_1.code;
             (void)_c;
             ret_val = 6;
-            (void)_c;
             goto epilogue;
             break;
         }
@@ -404,8 +404,6 @@ int reference_example(void) {
         (void)_ref_y;
         int* _ref_x = &x;
         (void)_ref_x;
-        (void)_ref_x;
-        (void)_ref_y;
     }
     Vec_int* values = ((Vec_int*)(ion_vec_new(sizeof(int))));
     ion_vec_push((ion_vec_t*)(values), &((int){x}), sizeof(int));
@@ -505,6 +503,8 @@ int spawn_channel_example(void) {
         goto epilogue;
     }
     ret_val = 0;
+    if (rx_back_mut.channel) { ion_channel_handle_drop(rx_back_mut.channel); }
+    if (tx.channel) { ion_channel_handle_drop(tx.channel); }
     goto epilogue;
 epilogue:
         return ret_val;
@@ -519,6 +519,7 @@ int fn_literal_example(void) {
         goto epilogue;
     }
     ret_val = 0;
+    (void)twice;
     goto epilogue;
 epilogue:
         return ret_val;
diff --git a/examples/spawn_channel.c b/examples/spawn_channel.c
@@ -52,6 +52,8 @@ int main(void) {
         goto epilogue;
     }
     ret_val = 1;
+    if (rx_back_mut.channel) { ion_channel_handle_drop(rx_back_mut.channel); }
+    if (tx.channel) { ion_channel_handle_drop(tx.channel); }
     goto epilogue;
 epilogue:
         return ret_val;
diff --git a/examples/text_summary/text_summary.c b/examples/text_summary/text_summary.c
diff --git a/src/cgen/mod.rs b/src/cgen/mod.rs

Original file line number	Diff line number	Diff line change
`@@ -228,13 +228,15 @@ int main(void) {`
`228`	`228`	`}`
`229`	`229`	`if (auth_failures != 1) {`
`230`	`230`	`ret_val = 2;`
	`231`	`+ if (done_rx_mut.channel) { ion_channel_handle_drop(done_rx_mut.channel); }`
`231`	`232`	`goto epilogue;`
`232`	`233`	`}`
`233`	`234`	`ion_string_t* server_line = fmt_int_to_string(server_errors);`
`234`	`235`	`io_println(server_line);`
`235`	`236`	`ion_string_t* auth_line = fmt_int_to_string(auth_failures);`
`236`	`237`	`io_println(auth_line);`
`237`	`238`	`ret_val = 0;`
	`239`	`+ if (done_rx_mut.channel) { ion_channel_handle_drop(done_rx_mut.channel); }`
`238`	`240`	`goto epilogue;`
`239`	`241`	`epilogue:`
`240`	`242`	`return ret_val;`
`@@ -244,11 +246,10 @@ void io_print(ion_string_t* ION_MAYBE_UNUSED s) {`
`244`	`246`	`{`
`245`	`247`	`int _result = write(1, s->data, (int)s->len);`
`246`	`248`	`(void)_result;`
`247`		`- (void)_result;`
`248`	`249`	`}`
	`250`	`+ if (s) { ion_string_free(s); }`
`249`	`251`	`goto epilogue;`
`250`	`252`	`epilogue:`
`251`		`- if (s) { ion_string_free(s); }`
`252`	`253`	`return;`
`253`	`254`	`}`
`254`	`255`
`@@ -258,24 +259,20 @@ void io_println(ion_string_t* ION_MAYBE_UNUSED s) {`
`258`	`259`	`(void)_result;`
`259`	`260`	`int _newline = write(1, (uint8_t*)"\n", 1);`
`260`	`261`	`(void)_newline;`
`261`		`- (void)_newline;`
`262`		`- (void)_result;`
`263`	`262`	`}`
	`263`	`+ if (s) { ion_string_free(s); }`
`264`	`264`	`goto epilogue;`
`265`	`265`	`epilogue:`
`266`		`- if (s) { ion_string_free(s); }`
`267`	`266`	`return;`
`268`	`267`	`}`
`269`	`268`
`270`	`269`	`void io_print_str(uint8_t* ION_MAYBE_UNUSED s, int ION_MAYBE_UNUSED len) {`
`271`	`270`	`if (len < 0) {`
`272`		`- (void)s;`
`273`		`- goto epilogue;`
	`271`	`+ goto epilogue;`
`274`	`272`	`}`
`275`	`273`	`{`
`276`	`274`	`int _result = write(1, s, len);`
`277`	`275`	`(void)_result;`
`278`		`- (void)_result;`
`279`	`276`	`}`
`280`	`277`	`goto epilogue;`
`281`	`278`	`epilogue:`
`@@ -291,7 +288,6 @@ void io_print_int(int ION_MAYBE_UNUSED n) {`
`291`	`288`	`{`
`292`	`289`	`int _result = write(1, (uint8_t*)"0", 1);`
`293`	`290`	`(void)_result;`
`294`		`- (void)_result;`
`295`	`291`	`}`
`296`	`292`	`(void)negative;`
`297`	`293`	`(void)len;`
`@@ -304,9 +300,11 @@ void io_print_int(int ION_MAYBE_UNUSED n) {`
`304`	`300`	`{`
`305`	`301`	`int _result = write(1, (uint8_t*)"-2147483648", 11);`
`306`	`302`	`(void)_result;`
`307`		`- (void)_result;`
`308`	`303`	`}`
`309`		`- goto epilogue;`
	`304`	`+ (void)negative;`
	`305`	`+ (void)len;`
	`306`	`+ (void)buf;`
	`307`	`+ goto epilogue;`
`310`	`308`	`}`
`311`	`309`	`value = (0 - value);`
`312`	`310`	`}`
`@@ -327,13 +325,11 @@ void io_print_int(int ION_MAYBE_UNUSED n) {`
`327`	`325`	`{`
`328`	`326`	`int _minus = write(1, (uint8_t*)"-", 1);`
`329`	`327`	`(void)_minus;`
`330`		`- (void)_minus;`
`331`	`328`	`}`
`332`	`329`	`}`
`333`	`330`	`{`
`334`	`331`	`int _result = write(1, &buf[0], len);`
`335`	`332`	`(void)_result;`
`336`		`- (void)_result;`
`337`	`333`	`}`
`338`	`334`	`goto epilogue;`
`339`	`335`	`epilogue:`
`@@ -352,7 +348,6 @@ void fmt_println_int(int ION_MAYBE_UNUSED n) {`
`352`	`348`	`{`
`353`	`349`	`int _newline = write(1, (uint8_t*)"\n", 1);`
`354`	`350`	`(void)_newline;`
`355`		`- (void)_newline;`
`356`	`351`	`}`
`357`	`352`	`goto epilogue;`
`358`	`353`	`epilogue:`
`@@ -379,6 +374,11 @@ ion_string_t* fmt_int_to_string(int ION_MAYBE_UNUSED n) {`
`379`	`374`	`negative = 1;`
`380`	`375`	`if (value == (-2147483648)) {`
`381`	`376`	`ret_val = ion_string_from_literal("-2147483648", 11);`
	`377`	`+ (void)result;`
	`378`	`+ (void)negative;`
	`379`	`+ (void)len;`
	`380`	`+ (void)buf;`
	`381`	`+ if (result) { ion_string_free(result); }`
`382`	`382`	`goto epilogue;`
`383`	`383`	`}`
`384`	`384`	`value = (0 - value);`
Original file line number	Diff line number	Diff line change
`@@ -65,6 +65,8 @@ int main(void) {`
`65`	`65`	`goto epilogue;`
`66`	`66`	`}`
`67`	`67`	`ret_val = 0;`
	`68`	`+ if (done_rx_mut.channel) { ion_channel_handle_drop(done_rx_mut.channel); }`
	`69`	`+ if (job_tx.channel) { ion_channel_handle_drop(job_tx.channel); }`
`68`	`70`	`goto epilogue;`
`69`	`71`	`epilogue:`
`70`	`72`	`return ret_val;`
Original file line number	Diff line number	Diff line change
`@@ -21,7 +21,6 @@ int main(void) {`
`21`	`21`	`{`
`22`	`22`	`int _result = write(1, (uint8_t*)"Hello, World!\n", 14);`
`23`	`23`	`(void)_result;`
`24`		`- (void)_result;`
`25`	`24`	`}`
`26`	`25`	`ret_val = 0;`
`27`	`26`	`goto epilogue;`
Original file line number	Diff line number	Diff line change
`@@ -33,11 +33,10 @@ void io_print(ion_string_t* ION_MAYBE_UNUSED s) {`
`33`	`33`	`{`
`34`	`34`	`int _result = write(1, s->data, (int)s->len);`
`35`	`35`	`(void)_result;`
`36`		`- (void)_result;`
`37`	`36`	`}`
	`37`	`+ if (s) { ion_string_free(s); }`
`38`	`38`	`goto epilogue;`
`39`	`39`	`epilogue:`
`40`		`- if (s) { ion_string_free(s); }`
`41`	`40`	`return;`
`42`	`41`	`}`
`43`	`42`
`@@ -47,24 +46,20 @@ void io_println(ion_string_t* ION_MAYBE_UNUSED s) {`
`47`	`46`	`(void)_result;`
`48`	`47`	`int _newline = write(1, (uint8_t*)"\n", 1);`
`49`	`48`	`(void)_newline;`
`50`		`- (void)_newline;`
`51`		`- (void)_result;`
`52`	`49`	`}`
	`50`	`+ if (s) { ion_string_free(s); }`
`53`	`51`	`goto epilogue;`
`54`	`52`	`epilogue:`
`55`		`- if (s) { ion_string_free(s); }`
`56`	`53`	`return;`
`57`	`54`	`}`
`58`	`55`
`59`	`56`	`void io_print_str(uint8_t* ION_MAYBE_UNUSED s, int ION_MAYBE_UNUSED len) {`
`60`	`57`	`if (len < 0) {`
`61`		`- (void)s;`
`62`		`- goto epilogue;`
	`58`	`+ goto epilogue;`
`63`	`59`	`}`
`64`	`60`	`{`
`65`	`61`	`int _result = write(1, s, len);`
`66`	`62`	`(void)_result;`
`67`		`- (void)_result;`
`68`	`63`	`}`
`69`	`64`	`goto epilogue;`
`70`	`65`	`epilogue:`
`@@ -80,7 +75,6 @@ void io_print_int(int ION_MAYBE_UNUSED n) {`
`80`	`75`	`{`
`81`	`76`	`int _result = write(1, (uint8_t*)"0", 1);`
`82`	`77`	`(void)_result;`
`83`		`- (void)_result;`
`84`	`78`	`}`
`85`	`79`	`(void)negative;`
`86`	`80`	`(void)len;`
`@@ -93,9 +87,11 @@ void io_print_int(int ION_MAYBE_UNUSED n) {`
`93`	`87`	`{`
`94`	`88`	`int _result = write(1, (uint8_t*)"-2147483648", 11);`
`95`	`89`	`(void)_result;`
`96`		`- (void)_result;`
`97`	`90`	`}`
`98`		`- goto epilogue;`
	`91`	`+ (void)negative;`
	`92`	`+ (void)len;`
	`93`	`+ (void)buf;`
	`94`	`+ goto epilogue;`
`99`	`95`	`}`
`100`	`96`	`value = (0 - value);`
`101`	`97`	`}`
`@@ -116,13 +112,11 @@ void io_print_int(int ION_MAYBE_UNUSED n) {`
`116`	`112`	`{`
`117`	`113`	`int _minus = write(1, (uint8_t*)"-", 1);`
`118`	`114`	`(void)_minus;`
`119`		`- (void)_minus;`
`120`	`115`	`}`
`121`	`116`	`}`
`122`	`117`	`{`
`123`	`118`	`int _result = write(1, &buf[0], len);`
`124`	`119`	`(void)_result;`
`125`		`- (void)_result;`
`126`	`120`	`}`
`127`	`121`	`goto epilogue;`
`128`	`122`	`epilogue:`
Original file line number	Diff line number	Diff line change
`@@ -52,6 +52,8 @@ int main(void) {`
`52`	`52`	`goto epilogue;`
`53`	`53`	`}`
`54`	`54`	`ret_val = 1;`
	`55`	`+ if (rx_back_mut.channel) { ion_channel_handle_drop(rx_back_mut.channel); }`
	`56`	`+ if (tx.channel) { ion_channel_handle_drop(tx.channel); }`
`55`	`57`	`goto epilogue;`
`56`	`58`	`epilogue:`
`57`	`59`	`return ret_val;`