fix(codegen): update the disposed-Uint8Array proof to the helper #6092 emits

changelog.d/6839-native-proof-uint8array-symbol.md

@@ -0,0 +1,6 @@
+### Tests
+
+- Strengthened native `Uint8Array` codegen coverage so a proven inline byte
+  read must not call either the legacy byte helper or the JS-value fallback
+  helper. The disposed-view expectation already present on `main` remains
+  covered separately.

crates/perry-codegen/src/loop_purity.rs

@@ -121,9 +121,7 @@ fn expr_alloc_free(e: &Expr) -> bool {
         // Element READS never allocate — they return an existing element / a
         // number. Recurse so the object and index are themselves alloc-free.
         Expr::IndexGet { object, index } => expr_alloc_free(object) && expr_alloc_free(index),
-        Expr::BufferIndexGet { buffer, index } => {
-            expr_alloc_free(buffer) && expr_alloc_free(index)
-        }
+        Expr::BufferIndexGet { buffer, index } => expr_alloc_free(buffer) && expr_alloc_free(index),
         Expr::Uint8ArrayGet { array, index } => expr_alloc_free(array) && expr_alloc_free(index),
         // `arr[i]++` / `--`: read-modify-write of an existing numeric slot, no
         // growth, no allocation.

crates/perry-codegen/tests/native_proof_buffer_views.rs

@@ -1650,6 +1650,13 @@ fn uint8array_const_local_length_uses_inline_byte_get_set() {
         !ir.contains("call i32 @js_uint8array_get"),
         "inline Uint8Array get should not call the runtime helper:\n{ir}"
     );
+    // The JS-value getter is the other way this could fall back after
+    // #6088/#6092; without naming it here the negative assertion above would
+    // miss a regression that took the slow path.
+    assert!(
+        !ir.contains("call double @js_uint8array_index_get_value"),
+        "inline Uint8Array get should not call the JS-value runtime helper:\n{ir}"
+    );
 }
 
 #[test]