fix(typecheck): print warning messages, and fix the unused-variable false positive

NOW.md

@@ -2,6 +2,14 @@
 
 Last updated: 2026-08-09
 
+## typecheck: warnings are PRINTED, and the unused-variable false positive is fixed (Refs #1948)
+
+- `typecheck` built every warning message and then dropped it: the OK branch printed only the total, so a warning was unactionable -- you could watch the number grow and never learn what it was. The messages were already in `result.errors`; they are printed now. Some are real correctness findings downgraded to warnings (a call to an undefined function, an argument type mismatch), so the silence actively hid defects
+- Printing them immediately exposed a detector bug: a BARE bracket literal (`[a0, 99]`, no `[N]Type{...}` prefix) never becomes child nodes -- the parser captures the whole bracket body as element TEXT in `extra_size`. The unused-variable pass read only children, so every identifier used that way was reported unused. That is the idiomatic "bind elements to locals, then rebuild the array" pattern (health_monitoring::update_health_check, key_management::set_key_slot, cross_layer_optimizer/redundancy_management::set_slot4). `collect_reads` now scans the element text too -- it can only ADD reads, so it removes false warnings and can never introduce one
+- tri-net corpus: unused-variable warnings 34 -> 14 (20 were false), total 788 -> 768; all 107 specs still typecheck clean
+- FROZEN_HASH resealed
+
+
 ## gen-zig: narrowing unsigned cast lowers to @truncate (Refs #1948)
 
 - t27 `as` truncates a narrowing integer cast (Rust semantics), but gen-zig always emitted checked `@intCast` -> panics in safe builds when the value does not fit (`weighted_total as u32` on a 2^32 multiple)

bootstrap/src/compiler.rs

@@ -13782,6 +13782,33 @@ pub fn typecheck_ast(ast: &Node) -> TypeCheckResult {
                 if node.kind == NodeKind::ExprIdentifier {
                     reads.insert(node.name.clone());
                 }
+                // A BARE bracket literal (`[a0, 99]`, no `[N]Type{...}` prefix)
+                // never becomes child nodes: the parser captures the whole
+                // bracket body as element TEXT in extra_size. Reading only
+                // children therefore missed every identifier used that way and
+                // reported it as an unused variable -- a false positive on the
+                // idiomatic "bind the elements to locals, then rebuild the
+                // array" pattern (health_monitoring::update_health_check,
+                // key_management::set_key_slot, and others). Scan the text too.
+                // This can only ADD reads, so it removes false warnings and can
+                // never introduce one.
+                if node.kind == NodeKind::ExprArrayLiteral && !node.extra_size.is_empty() {
+                    let mut ident = String::new();
+                    for ch in node.extra_size.chars() {
+                        if ch.is_alphanumeric() || ch == '_' {
+                            ident.push(ch);
+                        } else {
+                            if !ident.is_empty() && !ident.starts_with(|c: char| c.is_ascii_digit()) {
+                                reads.insert(std::mem::take(&mut ident));
+                            } else {
+                                ident.clear();
+                            }
+                        }
+                    }
+                    if !ident.is_empty() && !ident.starts_with(|c: char| c.is_ascii_digit()) {
+                        reads.insert(ident);
+                    }
+                }
                 for child in &node.children {
                     collect_reads(child, reads);
                 }

bootstrap/src/main.rs

@@ -4624,6 +4624,16 @@ fn run_typecheck(input_path: &str, json: bool) -> anyhow::Result<()> {
         println!("{}", serde_json::to_string_pretty(&resp).unwrap());
     } else if result.ok {
         println!("Typecheck OK (0 errors, {} warnings)", result.warnings);
+        // tri-net#375 pinned every spec's warning count, but the messages were
+        // built and then dropped on the floor: the OK branch printed only the
+        // total, so a warning was unactionable -- you could see the number grow
+        // and not what it was. They are already in result.errors; print them.
+        // Some of these are real correctness findings downgraded to warnings
+        // (a call to an undefined function, an argument type mismatch), so
+        // silence here actively hid defects.
+        for msg in &result.errors {
+            println!("  - {}", msg);
+        }
     } else {
         println!("Typecheck FAILED ({} errors, {} warnings):", result.error_count, result.warnings);
         for err in &result.errors {

bootstrap/stage0/FROZEN_HASH

@@ -1 +1 @@
-6c30e43706ecea81acaab117b97615d989a071d7973b4e390a78f7a794f69bb5
+cd2822f290eb04ed9b6a6530357fea22dff6e09a4fb1ad7575ffc7d6ec744ff7

docs/NOW.md

@@ -48,6 +48,14 @@ Last updated: 2026-08-09
 
 Last updated: 2026-08-09
 
+## typecheck: warnings are PRINTED, and the unused-variable false positive is fixed (Refs #1948)
+
+- `typecheck` built every warning message and then dropped it: the OK branch printed only the total, so a warning was unactionable -- you could watch the number grow and never learn what it was. The messages were already in `result.errors`; they are printed now. Some are real correctness findings downgraded to warnings (a call to an undefined function, an argument type mismatch), so the silence actively hid defects
+- Printing them immediately exposed a detector bug: a BARE bracket literal (`[a0, 99]`, no `[N]Type{...}` prefix) never becomes child nodes -- the parser captures the whole bracket body as element TEXT in `extra_size`. The unused-variable pass read only children, so every identifier used that way was reported unused. That is the idiomatic "bind elements to locals, then rebuild the array" pattern (health_monitoring::update_health_check, key_management::set_key_slot, cross_layer_optimizer/redundancy_management::set_slot4). `collect_reads` now scans the element text too -- it can only ADD reads, so it removes false warnings and can never introduce one
+- tri-net corpus: unused-variable warnings 34 -> 14 (20 were false), total 788 -> 768; all 107 specs still typecheck clean
+- FROZEN_HASH resealed
+
+
 ## numeric: GF-T registered in the catalog SSOT, all nine rungs (Refs #2001)
 
 - `specs/numeric/formats_catalog.t27` had **zero GF-T rows** -- the only `gft` id was `gfternary`, a different object (2-bit {-phi,0,+phi} alphabet, not a float with a balanced-ternary exponent field). Four rungs existed as specs with no row and no pack; five did not exist at all, while `zig-golden-float/specs/gft.tri` named this directory as its own source of truth