diff --git a/CLAUDE.md b/CLAUDE.md
index 189a4c3055..9ca2f2b4bb 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -8,7 +8,7 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 Perry is a native TypeScript compiler written in Rust that compiles TypeScript source code directly to native executables. It uses SWC for TypeScript parsing and LLVM for code generation.
 
-**Current Version:** 0.5.1327
+**Current Version:** 0.5.1328
 
 
 ## TypeScript Parity Status
diff --git a/Cargo.lock b/Cargo.lock
index a4c8f3ad8c..f93ee20ec9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5547,7 +5547,7 @@ checksum = "9b4f627cb1b25917193a259e49bdad08f671f8d9708acfd5fe0a8c1455d87220"
 
 [[package]]
 name = "perry"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "base64",
@@ -5607,14 +5607,14 @@ dependencies = [
 
 [[package]]
 name = "perry-api-manifest"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "serde",
 ]
 
 [[package]]
 name = "perry-audio-miniaudio"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "cc",
  "libc",
@@ -5622,7 +5622,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "inkwell",
@@ -5639,7 +5639,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen-arkts"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "perry-hir",
@@ -5647,7 +5647,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen-glance"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "perry-hir",
@@ -5655,7 +5655,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen-js"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "perry-dispatch",
@@ -5664,7 +5664,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen-swiftui"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "perry-hir",
@@ -5672,7 +5672,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen-wasm"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "base64",
@@ -5684,7 +5684,7 @@ dependencies = [
 
 [[package]]
 name = "perry-codegen-wear-tiles"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "perry-hir",
@@ -5692,7 +5692,7 @@ dependencies = [
 
 [[package]]
 name = "perry-container-compose"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -5721,14 +5721,14 @@ dependencies = [
 
 [[package]]
 name = "perry-container-e2e"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
 ]
 
 [[package]]
 name = "perry-diagnostics"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "serde",
  "serde_json",
@@ -5736,7 +5736,7 @@ dependencies = [
 
 [[package]]
 name = "perry-dispatch"
-version = "0.5.1327"
+version = "0.5.1328"
 
 [[package]]
 name = "perry-doc-fixture-my-bindings"
@@ -5747,7 +5747,7 @@ dependencies = [
 
 [[package]]
 name = "perry-doc-tests"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "clap",
@@ -5762,7 +5762,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-ads"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "block2",
  "objc2",
@@ -5772,7 +5772,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-argon2"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "argon2",
  "perry-ffi",
@@ -5780,7 +5780,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-axios"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
  "reqwest",
@@ -5789,7 +5789,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-bcrypt"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "bcrypt",
  "perry-ffi",
@@ -5797,7 +5797,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-better-sqlite3"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
  "rusqlite",
@@ -5805,7 +5805,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-cheerio"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
  "scraper",
@@ -5813,7 +5813,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-commander"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
  "perry-runtime",
@@ -5821,7 +5821,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-cron"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "chrono",
  "cron",
@@ -5831,7 +5831,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-dayjs"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "chrono",
  "perry-ffi",
@@ -5839,7 +5839,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-decimal"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
  "rust_decimal",
@@ -5847,7 +5847,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-dotenv"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
  "serde_json",
@@ -5855,7 +5855,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-ethers"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
  "rand 0.10.1",
@@ -5863,7 +5863,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-events"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
  "perry-runtime",
@@ -5871,14 +5871,14 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-exponential-backoff"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
 ]
 
 [[package]]
 name = "perry-ext-fastify"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "bytes",
  "http-body-util",
@@ -5896,7 +5896,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-fetch"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "bytes",
  "lazy_static",
@@ -5909,7 +5909,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-http"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "bytes",
  "h2",
@@ -5933,7 +5933,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-ioredis"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "lazy_static",
  "perry-ffi",
@@ -5943,7 +5943,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-jsonwebtoken"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "base64",
  "jsonwebtoken",
@@ -5954,7 +5954,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-lru-cache"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "lru",
  "perry-ffi",
@@ -5963,7 +5963,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-moment"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "chrono",
  "perry-ffi",
@@ -5971,7 +5971,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-mongodb"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "bson",
  "futures-util",
@@ -5983,7 +5983,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-mysql2"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "chrono",
  "perry-ffi",
@@ -5993,7 +5993,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-nanoid"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "nanoid",
  "perry-ffi",
@@ -6002,7 +6002,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-net"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "bytes",
  "perry-ffi",
@@ -6015,7 +6015,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-node-forge"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "const-oid 0.9.6",
  "der 0.7.10",
@@ -6034,7 +6034,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-nodemailer"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "lettre",
  "perry-ffi",
@@ -6044,7 +6044,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-pdf"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
  "printpdf",
@@ -6052,7 +6052,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-pg"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
  "sqlx",
@@ -6061,7 +6061,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-ratelimit"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "governor",
  "perry-ffi",
@@ -6069,7 +6069,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-sharp"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "fast_image_resize",
  "image",
@@ -6079,14 +6079,14 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-slugify"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
 ]
 
 [[package]]
 name = "perry-ext-streams"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "lazy_static",
  "perry-ffi",
@@ -6095,7 +6095,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-undici"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
  "perry-runtime",
@@ -6104,7 +6104,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-uuid"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
  "uuid",
@@ -6112,7 +6112,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-validator"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ffi",
  "regex",
@@ -6122,7 +6122,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-ws"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "futures-util",
  "lazy_static",
@@ -6135,7 +6135,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ext-zlib"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "brotli",
  "flate2",
@@ -6145,7 +6145,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ffi"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "dashmap",
  "once_cell",
@@ -6154,7 +6154,7 @@ dependencies = [
 
 [[package]]
 name = "perry-hir"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "perry-api-manifest",
@@ -6172,7 +6172,7 @@ dependencies = [
 
 [[package]]
 name = "perry-parser"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "perry-diagnostics",
@@ -6184,7 +6184,7 @@ dependencies = [
 
 [[package]]
 name = "perry-runtime"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "base64",
@@ -6226,14 +6226,14 @@ dependencies = [
 
 [[package]]
 name = "perry-runtime-static"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-runtime",
 ]
 
 [[package]]
 name = "perry-stdlib"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "aes 0.8.4",
  "aes 0.9.1",
@@ -6328,14 +6328,14 @@ dependencies = [
 
 [[package]]
 name = "perry-stdlib-static"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-stdlib",
 ]
 
 [[package]]
 name = "perry-transform"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "perry-hir",
@@ -6344,14 +6344,14 @@ dependencies = [
 
 [[package]]
 name = "perry-ui"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ui-model",
 ]
 
 [[package]]
 name = "perry-ui-android"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "base64",
  "itoa",
@@ -6368,7 +6368,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-geisterhand"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "rand 0.10.1",
  "serde",
@@ -6378,7 +6378,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-gtk4"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "base64",
  "cairo-rs 0.22.0",
@@ -6401,7 +6401,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-ios"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "base64",
  "block2",
@@ -6417,7 +6417,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-macos"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "base64",
  "block2",
@@ -6432,7 +6432,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-model"
-version = "0.5.1327"
+version = "0.5.1328"
 
 [[package]]
 name = "perry-ui-test"
@@ -6443,11 +6443,11 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-testkit"
-version = "0.5.1327"
+version = "0.5.1328"
 
 [[package]]
 name = "perry-ui-tvos"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "base64",
  "block2",
@@ -6463,7 +6463,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-visionos"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "base64",
  "block2",
@@ -6479,7 +6479,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-watchos"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "block2",
  "libc",
@@ -6492,7 +6492,7 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-windows"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "base64",
  "libc",
@@ -6509,14 +6509,14 @@ dependencies = [
 
 [[package]]
 name = "perry-ui-windows-winui"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "perry-ui-windows",
 ]
 
 [[package]]
 name = "perry-updater"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "anyhow",
  "base64",
@@ -6532,7 +6532,7 @@ dependencies = [
 
 [[package]]
 name = "perry-wasm-host"
-version = "0.5.1327"
+version = "0.5.1328"
 dependencies = [
  "wasmi",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index ccd9962c86..1913529c47 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -315,7 +315,7 @@ codegen-units = 16
 codegen-units = 16
 
 [workspace.package]
-version = "0.5.1327"
+version = "0.5.1328"
 edition = "2021"
 license = "MIT"
 repository = "https://github.com/PerryTS/perry"
diff --git a/changelog.d/7580-prealloc-boxes-module-global.md b/changelog.d/7580-prealloc-boxes-module-global.md
new file mode 100644
index 0000000000..13de671716
--- /dev/null
+++ b/changelog.d/7580-prealloc-boxes-module-global.md
@@ -0,0 +1,72 @@
+**fix(codegen): `PreallocateBoxes` no longer shadows a module-level global (#7521)**
+
+Every ES module with a top-level `{ … }` block containing a `function`
+declaration that read a sibling `let`/`const` compiled to a silently-empty
+binding:
+
+```ts
+import { anything } from "node:path";   // any import — it just makes the file strict
+{
+  const events: string[] = [];
+  function t(a: any) { events.push("fn:" + a); }
+  t("A");
+  console.log(events.length);   // node: 1   perry: 0
+}
+```
+
+Nothing threw, so the breakage was invisible except where a test happened to
+print the accumulated value. Object, number and string accumulators lost the
+same way — inside `t`, the captured binding simply read `undefined`, so
+`acc.n++` threw `Cannot read properties of undefined`. It surfaced as
+`test-files/test_gap_diagchannel_3082_3084_3085_3086.ts` printing an empty
+`events` array for the `#3086` `traceCallback` block, but neither
+`traceCallback`, nor closures, nor arrays were involved.
+
+Root cause: `emit_preallocate_boxes` (`crates/perry-codegen/src/stmt/mod.rs`)
+allocated a heap box — and, decisively, a `ctx.locals` slot — for every id in a
+`Stmt::PreallocateBoxes` directive, including ids that
+`codegen/module_globals_emit.rs` had already promoted to
+`@perry_global_<mod>__<id>`. Codegen already encodes the rule that the module
+global wins over the box (`ctx.boxed_vars.contains(id) &&
+!ctx.module_globals.contains_key(id)`, repeated at every read/write site in
+`expr/literals_vars.rs` and `stmt/let_stmt.rs`); this was the one place that did
+not check. The stale `ctx.locals` entry is consulted *before*
+`ctx.module_globals` on the `Stmt::Let` reuse path and the `LocalGet`/`LocalSet`
+store paths, so the declaration wrote into the local box-pointer slot, the
+module global was never stored, and the closure — which reads through the
+global, with zero captures — saw the `undefined` the global was defined with.
+
+The trigger was #7105's `lower_strict_block_fn_decls`, which made a bare block
+at the top level of a strict module emit `PreallocateBoxes` for the block's
+lexical bindings — the first time a promoted module-level id was ever handed to
+`emit_preallocate_boxes`. (#6853's window, suspected on the issue, is not
+involved.)
+
+Fix: skip promoted ids. The global is statically initialized to
+`TAG_UNDEFINED`, exactly what a non-TDZ prealloc box seeds. The TDZ variant is
+skipped too — module-global reads are a raw `load double @g` with no
+`js_box_get_bits` choke point, so seeding `TAG_TDZ` would leak the sentinel into
+arithmetic instead of throwing a `ReferenceError`.
+
+Regression coverage is an in-`src` unit module
+(`crates/perry-codegen/src/stmt/prealloc_module_global_tests.rs`), not a
+`crates/*/tests/*.rs` suite, so it runs in the per-PR `cargo-test` gate rather
+than only nightly (#5960) — the gap test that surfaced this is absent from
+`gap_snapshot.json` and *suppressed* by a stale `known_failures.json` entry (see
+below), and `parity` is tag-gated, which is why it sat unnoticed from
+2026-07-30. The two positive tests are
+sabotage-checked: reverting the `ctx.module_globals` guard takes both red while
+the fixture-premise test and the "#569/#6044 still gets its box" test stay
+green. The store assertion counts `store … ptr @perry_global_…` lines inside
+`main()` rather than using `contains` — `main` also takes the global's address
+for `js_gc_register_global_root`, which is emitted whether or not the
+declaration ever writes the cell, and that reference made the first draft of the
+test pass under sabotage.
+
+The stale `test-parity/known_failures.json` entry for
+`test_gap_diagchannel_3082_3084_3085_3086` (added 2026-07-04 for the original
+`#3082/#3084/#3085/#3086` feature cluster, long since implemented) is retired in
+the same change — that list is a pure suppression, so an entry whose test has
+started passing silences the regression forever rather than failing the way the
+`gc_root_dominance_allowlist` ratchet does. The test now byte-matches
+`node --experimental-strip-types` with exit 0 across all four blocks.
diff --git a/crates/perry-codegen/src/stmt/mod.rs b/crates/perry-codegen/src/stmt/mod.rs
index fe9f193369..a574e8cdf3 100644
--- a/crates/perry-codegen/src/stmt/mod.rs
+++ b/crates/perry-codegen/src/stmt/mod.rs
@@ -20,6 +20,8 @@ mod let_stmt;
 mod let_stmt_facts;
 mod loops;
 mod masked_window_region;
+#[cfg(test)]
+mod prealloc_module_global_tests;
 mod switch_stmt;
 mod try_stmt;
 mod unused_expr;
@@ -595,6 +597,33 @@ pub(crate) fn lower_stmt(ctx: &mut FnCtx<'_>, stmt: &Stmt) -> Result<()> {
 
 fn emit_preallocate_boxes(ctx: &mut FnCtx<'_>, ids: &[u32], tdz: bool) -> Result<()> {
     for id in ids {
+        // #7521: a module-level binding promoted to `@perry_global_<mod>__<id>`
+        // ALREADY has the shared, forward-visible, GC-rooted cell a prealloc box
+        // would provide, and every read/write site in codegen treats
+        // `module_globals` as winning over `boxed_vars` (`ctx.boxed_vars
+        // .contains(id) && !ctx.module_globals.contains_key(id)`). Allocating a
+        // box here anyway is not merely redundant — it registers a
+        // `ctx.locals` slot for the id, and `ctx.locals` is consulted BEFORE
+        // `ctx.module_globals` on both the `Stmt::Let` reuse path
+        // (`let_stmt.rs`) and the `LocalGet`/`LocalSet` store paths
+        // (`expr/literals_vars.rs`). The declaration then writes the value into
+        // the local box-pointer slot and the module global is never stored, so
+        // any function or closure that reads the binding through the global
+        // sees the `undefined` it was defined with. That is how a strict-mode
+        // block-scoped `function` declaration lost its entire captured
+        // environment once #7105 started emitting `PreallocateBoxes` for
+        // module-top-level blocks (`{ const events = []; function t(){
+        // events.push(x) } }` in any ES module — every push landed nowhere).
+        //
+        // The global is statically initialized to `TAG_UNDEFINED`, which is
+        // exactly what a non-TDZ prealloc box seeds. The TDZ variant is skipped
+        // too: module-global reads are raw `load double @g` with no
+        // `js_box_get_bits` choke point, so seeding `TAG_TDZ` there would leak
+        // the sentinel into arithmetic instead of throwing a ReferenceError —
+        // strictly worse than the `undefined` a forward read gets today.
+        if ctx.module_globals.contains_key(id) {
+            continue;
+        }
         if ctx.locals.contains_key(id) {
             // A previous PreallocateBoxes (or an unusual nesting)
             // already set this up -- skip to keep the existing slot.
diff --git a/crates/perry-codegen/src/stmt/prealloc_module_global_tests.rs b/crates/perry-codegen/src/stmt/prealloc_module_global_tests.rs
new file mode 100644
index 0000000000..9baf8b5950
--- /dev/null
+++ b/crates/perry-codegen/src/stmt/prealloc_module_global_tests.rs
@@ -0,0 +1,308 @@
+//! #7521: `Stmt::PreallocateBoxes` must not shadow a module-level global.
+//!
+//! A module-level binding that any function or closure reads is promoted to
+//! `@perry_global_<mod>__<id>` (`codegen/module_globals_emit.rs`) — a single,
+//! shared, GC-rooted, forward-visible cell. That is *also* what a prealloc box
+//! provides, so the two mechanisms are alternatives, and every read/write site
+//! in codegen already spells out which one wins:
+//!
+//! ```text
+//! ctx.boxed_vars.contains(id) && !ctx.module_globals.contains_key(id)
+//! ```
+//!
+//! `emit_preallocate_boxes` was the one place that did not check. Allocating a
+//! box for a promoted id is not merely redundant: it registers a `ctx.locals`
+//! slot, and `ctx.locals` is consulted BEFORE `ctx.module_globals` on the
+//! `Stmt::Let` reuse path (`let_stmt.rs`) and on the `LocalGet`/`LocalSet`
+//! store paths (`expr/literals_vars.rs`). The declaration then writes its value
+//! into the box-pointer slot, the global is never stored, and every closure
+//! that reads the binding through the global sees the `undefined` it was
+//! defined with.
+//!
+//! The user-visible shape (test-files/test_gap_diagchannel_3082_3084_3085_3086.ts,
+//! and any ES module at all after #7105 started emitting `PreallocateBoxes` for
+//! module-top-level blocks):
+//!
+//! ```js
+//! { const events = []; function t() { events.push("x"); } t(); events.length }
+//! ```
+//!
+//! `t()` ran, `events.length` was 0, and nothing threw — the push landed in a
+//! cell nobody else read.
+//!
+//! The assertions below are on emitted IR rather than on a flag, because the
+//! bug is precisely that a live, correct-looking box was built for a binding
+//! that stores somewhere else (CLAUDE.md: "a gate must assert its subject was
+//! live").
+
+use crate::{compile_module, AppMetadata, CompileOptions};
+use perry_hir::types::Type;
+use perry_hir::{Expr, Module, ModuleInitKind, Param, Stmt};
+
+fn ir_opts() -> CompileOptions {
+    CompileOptions {
+        target: None,
+        is_entry_module: true,
+        non_entry_module_prefixes: Vec::new(),
+        nextjs_path_init_modules: Vec::new(),
+        import_function_prefixes: std::collections::HashMap::new(),
+        import_function_ffi_aliases: std::collections::HashMap::new(),
+        import_function_origin_names: std::collections::HashMap::new(),
+        import_function_v8_specifiers: std::collections::HashMap::new(),
+        import_function_node_submodule: std::collections::HashMap::new(),
+        namespace_node_submodules: std::collections::HashMap::new(),
+        namespace_v8_specifiers: std::collections::HashMap::new(),
+        namespace_member_prefixes: std::collections::HashMap::new(),
+        namespace_member_origin_names: std::collections::HashMap::new(),
+        emit_ir_only: true,
+        verify_native_regions: false,
+        disable_buffer_fast_path: false,
+        namespace_imports: Vec::new(),
+        imported_classes: Vec::new(),
+        imported_enums: Vec::new(),
+        imported_async_funcs: std::collections::HashSet::new(),
+        type_aliases: std::collections::HashMap::new(),
+        imported_func_param_counts: std::collections::HashMap::new(),
+        imported_func_has_rest: std::collections::HashSet::new(),
+        imported_func_synthetic_arguments: std::collections::HashSet::new(),
+        imported_func_return_types: std::collections::HashMap::new(),
+        imported_vars: std::collections::HashSet::new(),
+        output_type: "executable".to_string(),
+        needs_stdlib: false,
+        needs_ui: false,
+        needs_geisterhand: false,
+        geisterhand_port: 7676,
+        enabled_features: Vec::new(),
+        native_module_init_names: Vec::new(),
+        js_module_specifiers: Vec::new(),
+        bundled_extensions: Vec::new(),
+        native_library_functions: Vec::new(),
+        i18n_table: None,
+        fast_math: false,
+        fp_contract_mode: crate::FpContractMode::Off,
+        app_metadata: AppMetadata::default(),
+        namespace_entries: Vec::new(),
+        dynamic_import_path_to_prefix: std::collections::HashMap::new(),
+        deferred_module_prefixes: std::collections::HashSet::new(),
+        module_init_deps: Vec::new(),
+        is_dynamic_import_target: false,
+        debug_locations: false,
+        module_source: None,
+        debug_source_line_offset: 0,
+    }
+}
+
+fn emit(m: &Module) -> String {
+    String::from_utf8(compile_module(m, ir_opts()).unwrap()).expect("LLVM IR should be UTF-8")
+}
+
+/// `function t(a) { events = a; }` — the hoisted block-level function
+/// declaration, as `lower_strict_block_fn_decls` leaves it: a `Stmt::Let`
+/// bound to a closure that both reads and writes the block's `const`, placed
+/// AHEAD of that const's own declaration.
+fn hoisted_writer(fn_local: u32, target: u32) -> Stmt {
+    Stmt::Let {
+        id: fn_local,
+        name: "t".to_string(),
+        ty: Type::Any,
+        mutable: false,
+        init: Some(Expr::Closure {
+            func_id: 1,
+            params: vec![Param {
+                id: 40,
+                name: "a".to_string(),
+                ty: Type::Any,
+                default: None,
+                decorators: Vec::new(),
+                is_rest: false,
+                arguments_object: None,
+            }],
+            return_type: Type::Any,
+            body: vec![Stmt::Expr(Expr::LocalSet(
+                target,
+                Box::new(Expr::LocalGet(40)),
+            ))],
+            captures: vec![target],
+            mutable_captures: vec![target],
+            captures_this: false,
+            captures_new_target: false,
+            enclosing_class: None,
+            is_arrow: false,
+            is_async: false,
+            is_generator: false,
+            is_strict: true,
+        }),
+    }
+}
+
+/// The exact module-init shape `lower_strict_block_fn_decls` produces for
+/// `{ const events = []; function t(a) { events = a } t(1) }` at the top level
+/// of an ES module: the prealloc directive, then the hoisted closure, then the
+/// binding's own declaration.
+///
+/// `prealloc` is a parameter so the "with" and "without" arms below are the
+/// same fixture, differing only in the statement under test.
+fn module_with_hoisted_block_fn(prealloc: bool) -> Module {
+    let mut m = Module::new("prealloc_global.ts");
+    let mut init = Vec::new();
+    if prealloc {
+        init.push(Stmt::PreallocateBoxes(vec![1]));
+    }
+    init.push(hoisted_writer(0, 1));
+    init.push(Stmt::Let {
+        id: 1,
+        name: "events".to_string(),
+        ty: Type::Any,
+        mutable: false,
+        init: Some(Expr::Array(Vec::new())),
+    });
+    init.push(Stmt::Expr(Expr::Call {
+        callee: Box::new(Expr::LocalGet(0)),
+        args: vec![Expr::Integer(1)],
+        type_args: Vec::new(),
+        byte_offset: 0,
+    }));
+    m.init = init;
+    m.init_kind = ModuleInitKind::Eager;
+    m
+}
+
+/// The slice of `ir` that is the entry module's init function (`main`), which
+/// is where the binding's own `Stmt::Let` is emitted. Deliberately excludes the
+/// closure body — the closure ALWAYS stored to the global, before and after the
+/// fix, so an assertion over the whole module would have been green throughout.
+fn main_body(ir: &str) -> &str {
+    let start = ir
+        .find("define i32 @main()")
+        .expect("entry module must emit main()");
+    let rest = &ir[start..];
+    let end = rest.find("\n}\n").map(|e| e + start).unwrap_or(ir.len());
+    &ir[start..end]
+}
+
+const GLOBAL: &str = "@perry_global_prealloc_global_ts__1";
+
+/// Count the STORES to the module global in `body`. A plain `contains` is not
+/// enough: `main` also takes the global's address for
+/// `js_gc_register_global_root`, and that reference is emitted whether or not
+/// the declaration ever writes the cell — it kept the pre-fix IR looking fine.
+fn stores_to_global(body: &str) -> usize {
+    body.lines()
+        .filter(|l| {
+            let l = l.trim();
+            l.starts_with("store ") && l.ends_with(&format!("ptr {GLOBAL}"))
+        })
+        .count()
+}
+
+/// Fixture premise. If `events` ever stops being promoted, the tests below
+/// would pass vacuously — they would be asserting about a global that no longer
+/// participates.
+#[test]
+fn the_captured_module_binding_is_promoted_to_a_global() {
+    for prealloc in [false, true] {
+        let ir = emit(&module_with_hoisted_block_fn(prealloc));
+        assert!(
+            ir.contains(&format!("{GLOBAL} = ")),
+            "premise (prealloc={prealloc}): a module-level binding read from a \
+             closure must be promoted to a module global"
+        );
+    }
+}
+
+/// The regression. `PreallocateBoxes` must not divert the declaration's store
+/// away from the shared cell.
+///
+/// Sabotage: delete the `ctx.module_globals.contains_key(id)` early-continue in
+/// `emit_preallocate_boxes` (`stmt/mod.rs`) and this goes red — the box-pointer
+/// slot swallows the store, `main` never touches the global, and every closure
+/// reading it sees `undefined`. That is #7521.
+#[test]
+fn a_preallocated_box_does_not_swallow_the_module_global_store() {
+    let ir = emit(&module_with_hoisted_block_fn(true));
+    let main = main_body(&ir);
+    assert!(
+        stores_to_global(main) > 0,
+        "#7521: the declaration `const events = []` must store into the shared \
+         module global, but main() never references {GLOBAL} as a store target. \
+         `emit_preallocate_boxes` registered a ctx.locals slot for a promoted \
+         id, and ctx.locals is consulted before ctx.module_globals on the \
+         Stmt::Let / LocalSet paths.\n--- main() ---\n{main}"
+    );
+}
+
+/// The prealloc arm must emit exactly what the no-prealloc arm emits for this
+/// binding: the directive is a no-op for a promoted id, not a different
+/// lowering that happens to also store the global.
+#[test]
+fn prealloc_is_a_no_op_for_a_promoted_binding() {
+    let with = emit(&module_with_hoisted_block_fn(true));
+    let without = emit(&module_with_hoisted_block_fn(false));
+    let count = |ir: &str| stores_to_global(main_body(ir));
+    assert_eq!(
+        count(&with),
+        count(&without),
+        "#7521: main() must STORE the module global the same number of times \
+         with and without PreallocateBoxes"
+    );
+    assert!(
+        !main_body(&with).contains("js_box_alloc_bits"),
+        "#7521: no box may be allocated in main() for a binding whose storage \
+         is already a module global\n--- main() ---\n{}",
+        main_body(&with)
+    );
+}
+
+/// The fix must not gut #569 / #6044. A prealloc'd id that is NOT a module
+/// global — the ordinary case, a `let`/`const` inside a function body captured
+/// by a hoisted sibling `function` — still needs its box.
+#[test]
+fn a_function_local_prealloc_still_gets_its_box() {
+    let mut m = Module::new("prealloc_local.ts");
+    // An arrow IIFE at module scope: its body's ids are function-locals, so
+    // nothing inside is eligible for module-global promotion.
+    let inner = vec![
+        Stmt::PreallocateBoxes(vec![11]),
+        hoisted_writer(10, 11),
+        Stmt::Let {
+            id: 11,
+            name: "events".to_string(),
+            ty: Type::Any,
+            mutable: false,
+            init: Some(Expr::Array(Vec::new())),
+        },
+        Stmt::Expr(Expr::Call {
+            callee: Box::new(Expr::LocalGet(10)),
+            args: vec![Expr::Integer(1)],
+            type_args: Vec::new(),
+            byte_offset: 0,
+        }),
+    ];
+    m.init = vec![Stmt::Expr(Expr::Call {
+        callee: Box::new(Expr::Closure {
+            func_id: 2,
+            params: Vec::new(),
+            return_type: Type::Any,
+            body: inner,
+            captures: Vec::new(),
+            mutable_captures: Vec::new(),
+            captures_this: false,
+            captures_new_target: false,
+            enclosing_class: None,
+            is_arrow: true,
+            is_async: false,
+            is_generator: false,
+            is_strict: true,
+        }),
+        args: Vec::new(),
+        type_args: Vec::new(),
+        byte_offset: 0,
+    })];
+    m.init_kind = ModuleInitKind::Eager;
+    let ir = emit(&m);
+    assert!(
+        ir.contains("js_box_alloc_bits"),
+        "#569/#6044: a prealloc'd id with no module global must still get a \
+         heap box — the #7521 guard is scoped to promoted ids only"
+    );
+}
diff --git a/test-parity/known_failures.json b/test-parity/known_failures.json
index 8609ce6486..18088a03f0 100644
--- a/test-parity/known_failures.json
+++ b/test-parity/known_failures.json
@@ -82,12 +82,6 @@
     "category": "gap-categorical",
     "reason": "console write validation — categorical console gap; standing per #5917."
   },
-  "test_gap_diagchannel_3082_3084_3085_3086": {
-    "issue": "3082",
-    "added": "2026-07-04",
-    "category": "bug-open",
-    "reason": "diagnostics_channel cluster (#3082/#3084/#3085/#3086); standing per #5917."
-  },
   "test_gap_dyn_index_get_denormal_safe": {
     "issue": "5917",
     "added": "2026-07-04",