From af7a215dd7f4fbf5e2361dbe2324cd670cdd53c6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ralph=20K=C3=BCpper?= <ralph3@skelpo.com>
Date: Tue, 6 Oct 2026 00:00:05 +0200
Subject: [PATCH] fix(class): keep specialization IDs unique across modules

---
 changelog.d/PENDING-recur2-class-ids.md       |    3 +
 crates/perry-hir/src/lib.rs                   |    2 +-
 crates/perry-hir/src/monomorph/context.rs     |    2 +-
 crates/perry-hir/src/monomorph/driver.rs      |   30 +-
 crates/perry-hir/src/monomorph/mod.rs         |    2 +-
 crates/perry-hir/src/monomorph/tests.rs       |  109 +-
 .../perry/src/commands/compile/bootstrap.rs   |   15 +-
 .../_helpers/recur_class_id_literals.ts       | 1102 +++++++++++++++++
 test-files/test_gap_recur_class_id_unique.ts  |   18 +
 9 files changed, 1233 insertions(+), 50 deletions(-)
 create mode 100644 changelog.d/PENDING-recur2-class-ids.md
 create mode 100644 test-files/_helpers/recur_class_id_literals.ts
 create mode 100644 test-files/test_gap_recur_class_id_unique.ts

diff --git a/changelog.d/PENDING-recur2-class-ids.md b/changelog.d/PENDING-recur2-class-ids.md
new file mode 100644
index 0000000000..9ba512cebd
--- /dev/null
+++ b/changelog.d/PENDING-recur2-class-ids.md
@@ -0,0 +1,3 @@
+Generic class specializations now allocate class IDs from one sequence above all declared classes and object-literal shapes in the program. The old per-module maximum plus 1,000 could reuse another module's literal ID, making a class instance's shape claim the default `Object.prototype` edge. This preserves the shape-based prototype fast path while restoring the declared class prototype and inherited methods on descriptor clones, including Effect 4 Schema initialization.
+
+Adds a multi-module gap regression with 1,100 distinct literal shapes and a HIR unit test covering specialization IDs and origin metadata across modules. The regression first became observable in `993bcb2e9704bf9596cc1710c8373060b4372cab` (PR #12024); its parent `8ec553a709` matches Node.
diff --git a/crates/perry-hir/src/lib.rs b/crates/perry-hir/src/lib.rs
index 84d71b177e..f810168048 100644
--- a/crates/perry-hir/src/lib.rs
+++ b/crates/perry-hir/src/lib.rs
@@ -71,7 +71,7 @@ pub use lower::{
     lower_module_with_class_id, lower_module_with_class_id_and_types,
     lower_module_with_class_id_types_and_seed, lower_module_with_class_id_types_seed_and_entry,
 };
-pub use monomorph::monomorphize_module;
+pub use monomorph::{monomorphize_module, monomorphize_modules};
 pub use native_profile::exported_native_pod_abi;
 pub use patched_builtins::{
     clear_patched_builtins, patched_prototype_methods, scan_module as scan_patched_builtins,
diff --git a/crates/perry-hir/src/monomorph/context.rs b/crates/perry-hir/src/monomorph/context.rs
index f8f41ef451..64b4320e00 100644
--- a/crates/perry-hir/src/monomorph/context.rs
+++ b/crates/perry-hir/src/monomorph/context.rs
@@ -106,7 +106,7 @@ impl MonomorphizationContext {
             func_work_queue: VecDeque::new(),
             class_work_queue: VecDeque::new(),
             next_func_id: max_func_id + 1000, // Leave room for original IDs
-            next_class_id: max_class_id + 1000,
+            next_class_id: max_class_id + 1,
             processed_funcs: HashSet::new(),
             processed_classes: HashSet::new(),
         }
diff --git a/crates/perry-hir/src/monomorph/driver.rs b/crates/perry-hir/src/monomorph/driver.rs
index b6601bb6a4..0158ddc06d 100644
--- a/crates/perry-hir/src/monomorph/driver.rs
+++ b/crates/perry-hir/src/monomorph/driver.rs
@@ -3,11 +3,35 @@ use super::*;
 /// Main monomorphization pass
 /// Processes the module and generates specialized versions of generic functions/classes
 pub fn monomorphize_module(module: &mut Module) {
-    let mut ctx = MonomorphizationContext::new(module);
+    monomorphize_modules(std::iter::once(module));
+}
+
+/// Specialize a program's modules using one class-ID allocation sequence.
+/// Lowering has already assigned IDs to declared classes and literal shapes;
+/// every specialization must be above that whole program's range, not just
+/// above the classes in its own module.
+pub fn monomorphize_modules<'a>(modules: impl IntoIterator<Item = &'a mut Module>) {
+    let modules: Vec<_> = modules.into_iter().collect();
+    let mut next_class_id = modules
+        .iter()
+        .flat_map(|module| &module.classes)
+        .map(|class| class.id)
+        .max()
+        .unwrap_or(0)
+        + 1;
+    for module in modules {
+        let mut ctx = MonomorphizationContext::new(module);
+        ctx.next_class_id = next_class_id;
+        monomorphize_with_context(module, &mut ctx);
+        next_class_id = ctx.next_class_id;
+    }
+}
+
+fn monomorphize_with_context(module: &mut Module, ctx: &mut MonomorphizationContext) {
     let idx = ModuleIndex::new(module);
 
     // First pass: collect all generic instantiations from the code
-    collect_instantiations(module, &mut ctx, &idx);
+    collect_instantiations(module, ctx, &idx);
 
     // Process work queues until empty
     let mut new_functions = Vec::new();
@@ -116,7 +140,7 @@ pub fn monomorphize_module(module: &mut Module) {
     }
 
     // Update call sites to use specialized versions
-    update_call_sites(module, &ctx);
+    update_call_sites(module, ctx);
 
     // Fill in default arguments for constructor calls
     fill_default_arguments(module);
diff --git a/crates/perry-hir/src/monomorph/mod.rs b/crates/perry-hir/src/monomorph/mod.rs
index 9dead6cfad..503de18e3a 100644
--- a/crates/perry-hir/src/monomorph/mod.rs
+++ b/crates/perry-hir/src/monomorph/mod.rs
@@ -34,7 +34,7 @@ mod tests;
 
 pub use constraints::ConstraintError;
 pub use context::MonomorphizationContext;
-pub use driver::monomorphize_module;
+pub use driver::{monomorphize_module, monomorphize_modules};
 pub use specialize::{specialize_class, specialize_function};
 pub use substitute_type::substitute_type;
 
diff --git a/crates/perry-hir/src/monomorph/tests.rs b/crates/perry-hir/src/monomorph/tests.rs
index a405c7ea5b..7c48b555d8 100644
--- a/crates/perry-hir/src/monomorph/tests.rs
+++ b/crates/perry-hir/src/monomorph/tests.rs
@@ -948,39 +948,6 @@ fn assert_specialized_call(expr: &Expr, module: &Module, expected_name: &str) {
 /// red for days (#5960). This runs on every PR.
 #[test]
 fn a_specialized_class_reports_the_generics_display_name() {
-    fn generic_class(id: u32, name: &str) -> Class {
-        Class {
-            id,
-            name: name.to_string(),
-            type_params: vec![TypeParam {
-                name: "T".to_string(),
-                constraint: None,
-                default: None,
-            }],
-            extends: None,
-            extends_name: None,
-            native_extends: None,
-            extends_expr: None,
-            heritage_lexically_shadowed: false,
-            fields: vec![],
-            constructor: None,
-            methods: vec![],
-            getters: vec![],
-            setters: vec![],
-            static_accessor_names: vec![],
-            static_accessor_fn_ids: vec![],
-            static_fields: vec![],
-            static_methods: vec![],
-            computed_members: vec![],
-            decorators: vec![],
-            is_exported: false,
-            aliases: vec![],
-            is_nested: false,
-            alloc_width_hint: 0,
-            specialized_from: None,
-        }
-    }
-
     let mut module = Module::new("test");
     module.classes.push(generic_class(1, "Gen"));
     module.init.push(Stmt::Expr(Expr::New {
@@ -1233,3 +1200,79 @@ fn fill_defaults_pads_before_appended_class_captures() {
         "the trailing capture args must be the captured values, not padding: {args:?}"
     );
 }
+
+fn generic_class(id: u32, name: &str) -> Class {
+    Class {
+        id,
+        name: name.to_string(),
+        type_params: vec![TypeParam {
+            name: "T".to_string(),
+            constraint: None,
+            default: None,
+        }],
+        extends: None,
+        extends_name: None,
+        native_extends: None,
+        extends_expr: None,
+        heritage_lexically_shadowed: false,
+        fields: vec![],
+        constructor: None,
+        methods: vec![],
+        getters: vec![],
+        setters: vec![],
+        static_accessor_names: vec![],
+        static_accessor_fn_ids: vec![],
+        static_fields: vec![],
+        static_methods: vec![],
+        computed_members: vec![],
+        decorators: vec![],
+        is_exported: false,
+        aliases: vec![],
+        is_nested: false,
+        alloc_width_hint: 0,
+        specialized_from: None,
+    }
+}
+
+#[test]
+fn specializations_do_not_reuse_other_modules_class_or_literal_ids() {
+    let mut first = Module::new("first");
+    first.classes.push(generic_class(1, "First"));
+    let mut second = Module::new("second");
+    second.classes.push(generic_class(2, "Second"));
+    let mut literal = generic_class(1001, "Literal");
+    literal.type_params.clear();
+    second.classes.push(literal);
+    let mut third = Module::new("third");
+    let mut last_literal = generic_class(1100, "LastLiteral");
+    last_literal.type_params.clear();
+    third.classes.push(last_literal);
+
+    for (module, name) in [(&mut first, "First"), (&mut second, "Second")] {
+        for ty in [Type::Number, Type::String] {
+            module.init.push(Stmt::Expr(Expr::New {
+                class_name: name.to_string(),
+                args: vec![],
+                type_args: vec![ty],
+                byte_offset: 0,
+                cap_args_appended: 0,
+            }));
+        }
+    }
+    monomorphize_modules([&mut first, &mut second, &mut third]);
+
+    let mut ids = HashSet::new();
+    let mut specializations = 0;
+    for module in [&first, &second, &third] {
+        for class in &module.classes {
+            assert!(ids.insert(class.id), "duplicate class ID {}", class.id);
+            if let Some(origin) = &class.specialized_from {
+                specializations += 1;
+                assert!(class.id > 1100, "specialization overlaps lowered IDs");
+                assert_eq!(module.class_display_names.get(&class.id), Some(origin));
+            }
+        }
+    }
+    assert_eq!(specializations, 4);
+    assert_eq!(ids.len(), 8);
+}
diff --git a/crates/perry/src/commands/compile/bootstrap.rs b/crates/perry/src/commands/compile/bootstrap.rs
index e053c486f4..25721cd21d 100644
--- a/crates/perry/src/commands/compile/bootstrap.rs
+++ b/crates/perry/src/commands/compile/bootstrap.rs
@@ -1073,16 +1073,9 @@ pub(super) fn run_native_instance_fixups(ctx: &mut CompilationContext) {
         }
     }
 
-    // Cross-module fix → local-fix re-run → monomorphize (parallel,
-    // fused per-module). Tier 4.2: pre-fix this was three separate
-    // `par_iter_mut().for_each(...)` passes. The local-fix re-run
-    // depends on `fix_cross_module_native_instances` having
-    // populated cross-module type info on this module, and
-    // monomorphize depends on the post-local-fix module shape — but
-    // both dependencies are intra-module, so running all three in
-    // one rayon job per module is safe and saves two scheduler
-    // round-trips. The cross-module step is gated on at least one
-    // export existing (skip the call entirely otherwise).
+    // Cross-module and local native-instance fixes remain module-local and
+    // parallel. Specialization below must share a class-ID allocator across
+    // the entire program, including every module's object-literal shapes.
     let has_native_exports =
         !exported_instances.is_empty() || !exported_func_return_instances.is_empty();
     ctx.native_modules
@@ -1101,8 +1094,8 @@ pub(super) fn run_native_instance_fixups(ctx: &mut CompilationContext) {
             // is false this is effectively a no-op since nothing changed
             // since the first local-fix in Pass A above.
             perry_hir::fix_local_native_instances(hir_module);
-            perry_hir::monomorphize_module(hir_module);
         });
+    perry_hir::monomorphize_modules(ctx.native_modules.iter_mut().map(|(_, module)| module));
 }
 
 /// --- HarmonyOS Phase 2: harvest perry/ui App({body: ...}) into ArkUI ---
diff --git a/test-files/_helpers/recur_class_id_literals.ts b/test-files/_helpers/recur_class_id_literals.ts
new file mode 100644
index 0000000000..3bec92a25d
--- /dev/null
+++ b/test-files/_helpers/recur_class_id_literals.ts
@@ -0,0 +1,1102 @@
+export const literals = [
+  { p0: 0 },
+  { p1: 1 },
+  { p2: 2 },
+  { p3: 3 },
+  { p4: 4 },
+  { p5: 5 },
+  { p6: 6 },
+  { p7: 7 },
+  { p8: 8 },
+  { p9: 9 },
+  { p10: 10 },
+  { p11: 11 },
+  { p12: 12 },
+  { p13: 13 },
+  { p14: 14 },
+  { p15: 15 },
+  { p16: 16 },
+  { p17: 17 },
+  { p18: 18 },
+  { p19: 19 },
+  { p20: 20 },
+  { p21: 21 },
+  { p22: 22 },
+  { p23: 23 },
+  { p24: 24 },
+  { p25: 25 },
+  { p26: 26 },
+  { p27: 27 },
+  { p28: 28 },
+  { p29: 29 },
+  { p30: 30 },
+  { p31: 31 },
+  { p32: 32 },
+  { p33: 33 },
+  { p34: 34 },
+  { p35: 35 },
+  { p36: 36 },
+  { p37: 37 },
+  { p38: 38 },
+  { p39: 39 },
+  { p40: 40 },
+  { p41: 41 },
+  { p42: 42 },
+  { p43: 43 },
+  { p44: 44 },
+  { p45: 45 },
+  { p46: 46 },
+  { p47: 47 },
+  { p48: 48 },
+  { p49: 49 },
+  { p50: 50 },
+  { p51: 51 },
+  { p52: 52 },
+  { p53: 53 },
+  { p54: 54 },
+  { p55: 55 },
+  { p56: 56 },
+  { p57: 57 },
+  { p58: 58 },
+  { p59: 59 },
+  { p60: 60 },
+  { p61: 61 },
+  { p62: 62 },
+  { p63: 63 },
+  { p64: 64 },
+  { p65: 65 },
+  { p66: 66 },
+  { p67: 67 },
+  { p68: 68 },
+  { p69: 69 },
+  { p70: 70 },
+  { p71: 71 },
+  { p72: 72 },
+  { p73: 73 },
+  { p74: 74 },
+  { p75: 75 },
+  { p76: 76 },
+  { p77: 77 },
+  { p78: 78 },
+  { p79: 79 },
+  { p80: 80 },
+  { p81: 81 },
+  { p82: 82 },
+  { p83: 83 },
+  { p84: 84 },
+  { p85: 85 },
+  { p86: 86 },
+  { p87: 87 },
+  { p88: 88 },
+  { p89: 89 },
+  { p90: 90 },
+  { p91: 91 },
+  { p92: 92 },
+  { p93: 93 },
+  { p94: 94 },
+  { p95: 95 },
+  { p96: 96 },
+  { p97: 97 },
+  { p98: 98 },
+  { p99: 99 },
+  { p100: 100 },
+  { p101: 101 },
+  { p102: 102 },
+  { p103: 103 },
+  { p104: 104 },
+  { p105: 105 },
+  { p106: 106 },
+  { p107: 107 },
+  { p108: 108 },
+  { p109: 109 },
+  { p110: 110 },
+  { p111: 111 },
+  { p112: 112 },
+  { p113: 113 },
+  { p114: 114 },
+  { p115: 115 },
+  { p116: 116 },
+  { p117: 117 },
+  { p118: 118 },
+  { p119: 119 },
+  { p120: 120 },
+  { p121: 121 },
+  { p122: 122 },
+  { p123: 123 },
+  { p124: 124 },
+  { p125: 125 },
+  { p126: 126 },
+  { p127: 127 },
+  { p128: 128 },
+  { p129: 129 },
+  { p130: 130 },
+  { p131: 131 },
+  { p132: 132 },
+  { p133: 133 },
+  { p134: 134 },
+  { p135: 135 },
+  { p136: 136 },
+  { p137: 137 },
+  { p138: 138 },
+  { p139: 139 },
+  { p140: 140 },
+  { p141: 141 },
+  { p142: 142 },
+  { p143: 143 },
+  { p144: 144 },
+  { p145: 145 },
+  { p146: 146 },
+  { p147: 147 },
+  { p148: 148 },
+  { p149: 149 },
+  { p150: 150 },
+  { p151: 151 },
+  { p152: 152 },
+  { p153: 153 },
+  { p154: 154 },
+  { p155: 155 },
+  { p156: 156 },
+  { p157: 157 },
+  { p158: 158 },
+  { p159: 159 },
+  { p160: 160 },
+  { p161: 161 },
+  { p162: 162 },
+  { p163: 163 },
+  { p164: 164 },
+  { p165: 165 },
+  { p166: 166 },
+  { p167: 167 },
+  { p168: 168 },
+  { p169: 169 },
+  { p170: 170 },
+  { p171: 171 },
+  { p172: 172 },
+  { p173: 173 },
+  { p174: 174 },
+  { p175: 175 },
+  { p176: 176 },
+  { p177: 177 },
+  { p178: 178 },
+  { p179: 179 },
+  { p180: 180 },
+  { p181: 181 },
+  { p182: 182 },
+  { p183: 183 },
+  { p184: 184 },
+  { p185: 185 },
+  { p186: 186 },
+  { p187: 187 },
+  { p188: 188 },
+  { p189: 189 },
+  { p190: 190 },
+  { p191: 191 },
+  { p192: 192 },
+  { p193: 193 },
+  { p194: 194 },
+  { p195: 195 },
+  { p196: 196 },
+  { p197: 197 },
+  { p198: 198 },
+  { p199: 199 },
+  { p200: 200 },
+  { p201: 201 },
+  { p202: 202 },
+  { p203: 203 },
+  { p204: 204 },
+  { p205: 205 },
+  { p206: 206 },
+  { p207: 207 },
+  { p208: 208 },
+  { p209: 209 },
+  { p210: 210 },
+  { p211: 211 },
+  { p212: 212 },
+  { p213: 213 },
+  { p214: 214 },
+  { p215: 215 },
+  { p216: 216 },
+  { p217: 217 },
+  { p218: 218 },
+  { p219: 219 },
+  { p220: 220 },
+  { p221: 221 },
+  { p222: 222 },
+  { p223: 223 },
+  { p224: 224 },
+  { p225: 225 },
+  { p226: 226 },
+  { p227: 227 },
+  { p228: 228 },
+  { p229: 229 },
+  { p230: 230 },
+  { p231: 231 },
+  { p232: 232 },
+  { p233: 233 },
+  { p234: 234 },
+  { p235: 235 },
+  { p236: 236 },
+  { p237: 237 },
+  { p238: 238 },
+  { p239: 239 },
+  { p240: 240 },
+  { p241: 241 },
+  { p242: 242 },
+  { p243: 243 },
+  { p244: 244 },
+  { p245: 245 },
+  { p246: 246 },
+  { p247: 247 },
+  { p248: 248 },
+  { p249: 249 },
+  { p250: 250 },
+  { p251: 251 },
+  { p252: 252 },
+  { p253: 253 },
+  { p254: 254 },
+  { p255: 255 },
+  { p256: 256 },
+  { p257: 257 },
+  { p258: 258 },
+  { p259: 259 },
+  { p260: 260 },
+  { p261: 261 },
+  { p262: 262 },
+  { p263: 263 },
+  { p264: 264 },
+  { p265: 265 },
+  { p266: 266 },
+  { p267: 267 },
+  { p268: 268 },
+  { p269: 269 },
+  { p270: 270 },
+  { p271: 271 },
+  { p272: 272 },
+  { p273: 273 },
+  { p274: 274 },
+  { p275: 275 },
+  { p276: 276 },
+  { p277: 277 },
+  { p278: 278 },
+  { p279: 279 },
+  { p280: 280 },
+  { p281: 281 },
+  { p282: 282 },
+  { p283: 283 },
+  { p284: 284 },
+  { p285: 285 },
+  { p286: 286 },
+  { p287: 287 },
+  { p288: 288 },
+  { p289: 289 },
+  { p290: 290 },
+  { p291: 291 },
+  { p292: 292 },
+  { p293: 293 },
+  { p294: 294 },
+  { p295: 295 },
+  { p296: 296 },
+  { p297: 297 },
+  { p298: 298 },
+  { p299: 299 },
+  { p300: 300 },
+  { p301: 301 },
+  { p302: 302 },
+  { p303: 303 },
+  { p304: 304 },
+  { p305: 305 },
+  { p306: 306 },
+  { p307: 307 },
+  { p308: 308 },
+  { p309: 309 },
+  { p310: 310 },
+  { p311: 311 },
+  { p312: 312 },
+  { p313: 313 },
+  { p314: 314 },
+  { p315: 315 },
+  { p316: 316 },
+  { p317: 317 },
+  { p318: 318 },
+  { p319: 319 },
+  { p320: 320 },
+  { p321: 321 },
+  { p322: 322 },
+  { p323: 323 },
+  { p324: 324 },
+  { p325: 325 },
+  { p326: 326 },
+  { p327: 327 },
+  { p328: 328 },
+  { p329: 329 },
+  { p330: 330 },
+  { p331: 331 },
+  { p332: 332 },
+  { p333: 333 },
+  { p334: 334 },
+  { p335: 335 },
+  { p336: 336 },
+  { p337: 337 },
+  { p338: 338 },
+  { p339: 339 },
+  { p340: 340 },
+  { p341: 341 },
+  { p342: 342 },
+  { p343: 343 },
+  { p344: 344 },
+  { p345: 345 },
+  { p346: 346 },
+  { p347: 347 },
+  { p348: 348 },
+  { p349: 349 },
+  { p350: 350 },
+  { p351: 351 },
+  { p352: 352 },
+  { p353: 353 },
+  { p354: 354 },
+  { p355: 355 },
+  { p356: 356 },
+  { p357: 357 },
+  { p358: 358 },
+  { p359: 359 },
+  { p360: 360 },
+  { p361: 361 },
+  { p362: 362 },
+  { p363: 363 },
+  { p364: 364 },
+  { p365: 365 },
+  { p366: 366 },
+  { p367: 367 },
+  { p368: 368 },
+  { p369: 369 },
+  { p370: 370 },
+  { p371: 371 },
+  { p372: 372 },
+  { p373: 373 },
+  { p374: 374 },
+  { p375: 375 },
+  { p376: 376 },
+  { p377: 377 },
+  { p378: 378 },
+  { p379: 379 },
+  { p380: 380 },
+  { p381: 381 },
+  { p382: 382 },
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+  { p569: 569 },
+  { p570: 570 },
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+  { p573: 573 },
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+  { p585: 585 },
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+  { p590: 590 },
+  { p591: 591 },
+  { p592: 592 },
+  { p593: 593 },
+  { p594: 594 },
+  { p595: 595 },
+  { p596: 596 },
+  { p597: 597 },
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+  { p599: 599 },
+  { p600: 600 },
+  { p601: 601 },
+  { p602: 602 },
+  { p603: 603 },
+  { p604: 604 },
+  { p605: 605 },
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+  { p611: 611 },
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+  { p613: 613 },
+  { p614: 614 },
+  { p615: 615 },
+  { p616: 616 },
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+  { p618: 618 },
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+  { p620: 620 },
+  { p621: 621 },
+  { p622: 622 },
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+  { p641: 641 },
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+  { p648: 648 },
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+  { p650: 650 },
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+  { p655: 655 },
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+  { p660: 660 },
+  { p661: 661 },
+  { p662: 662 },
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+  { p665: 665 },
+  { p666: 666 },
+  { p667: 667 },
+  { p668: 668 },
+  { p669: 669 },
+  { p670: 670 },
+  { p671: 671 },
+  { p672: 672 },
+  { p673: 673 },
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+  { p676: 676 },
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+  { p692: 692 },
+  { p693: 693 },
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+  { p697: 697 },
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+  { p699: 699 },
+  { p700: 700 },
+  { p701: 701 },
+  { p702: 702 },
+  { p703: 703 },
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+  { p705: 705 },
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+  { p707: 707 },
+  { p708: 708 },
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+  { p710: 710 },
+  { p711: 711 },
+  { p712: 712 },
+  { p713: 713 },
+  { p714: 714 },
+  { p715: 715 },
+  { p716: 716 },
+  { p717: 717 },
+  { p718: 718 },
+  { p719: 719 },
+  { p720: 720 },
+  { p721: 721 },
+  { p722: 722 },
+  { p723: 723 },
+  { p724: 724 },
+  { p725: 725 },
+  { p726: 726 },
+  { p727: 727 },
+  { p728: 728 },
+  { p729: 729 },
+  { p730: 730 },
+  { p731: 731 },
+  { p732: 732 },
+  { p733: 733 },
+  { p734: 734 },
+  { p735: 735 },
+  { p736: 736 },
+  { p737: 737 },
+  { p738: 738 },
+  { p739: 739 },
+  { p740: 740 },
+  { p741: 741 },
+  { p742: 742 },
+  { p743: 743 },
+  { p744: 744 },
+  { p745: 745 },
+  { p746: 746 },
+  { p747: 747 },
+  { p748: 748 },
+  { p749: 749 },
+  { p750: 750 },
+  { p751: 751 },
+  { p752: 752 },
+  { p753: 753 },
+  { p754: 754 },
+  { p755: 755 },
+  { p756: 756 },
+  { p757: 757 },
+  { p758: 758 },
+  { p759: 759 },
+  { p760: 760 },
+  { p761: 761 },
+  { p762: 762 },
+  { p763: 763 },
+  { p764: 764 },
+  { p765: 765 },
+  { p766: 766 },
+  { p767: 767 },
+  { p768: 768 },
+  { p769: 769 },
+  { p770: 770 },
+  { p771: 771 },
+  { p772: 772 },
+  { p773: 773 },
+  { p774: 774 },
+  { p775: 775 },
+  { p776: 776 },
+  { p777: 777 },
+  { p778: 778 },
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+  { p780: 780 },
+  { p781: 781 },
+  { p782: 782 },
+  { p783: 783 },
+  { p784: 784 },
+  { p785: 785 },
+  { p786: 786 },
+  { p787: 787 },
+  { p788: 788 },
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+  { p791: 791 },
+  { p792: 792 },
+  { p793: 793 },
+  { p794: 794 },
+  { p795: 795 },
+  { p796: 796 },
+  { p797: 797 },
+  { p798: 798 },
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+  { p801: 801 },
+  { p802: 802 },
+  { p803: 803 },
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+  { p805: 805 },
+  { p806: 806 },
+  { p807: 807 },
+  { p808: 808 },
+  { p809: 809 },
+  { p810: 810 },
+  { p811: 811 },
+  { p812: 812 },
+  { p813: 813 },
+  { p814: 814 },
+  { p815: 815 },
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+  { p817: 817 },
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+  { p819: 819 },
+  { p820: 820 },
+  { p821: 821 },
+  { p822: 822 },
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+  { p824: 824 },
+  { p825: 825 },
+  { p826: 826 },
+  { p827: 827 },
+  { p828: 828 },
+  { p829: 829 },
+  { p830: 830 },
+  { p831: 831 },
+  { p832: 832 },
+  { p833: 833 },
+  { p834: 834 },
+  { p835: 835 },
+  { p836: 836 },
+  { p837: 837 },
+  { p838: 838 },
+  { p839: 839 },
+  { p840: 840 },
+  { p841: 841 },
+  { p842: 842 },
+  { p843: 843 },
+  { p844: 844 },
+  { p845: 845 },
+  { p846: 846 },
+  { p847: 847 },
+  { p848: 848 },
+  { p849: 849 },
+  { p850: 850 },
+  { p851: 851 },
+  { p852: 852 },
+  { p853: 853 },
+  { p854: 854 },
+  { p855: 855 },
+  { p856: 856 },
+  { p857: 857 },
+  { p858: 858 },
+  { p859: 859 },
+  { p860: 860 },
+  { p861: 861 },
+  { p862: 862 },
+  { p863: 863 },
+  { p864: 864 },
+  { p865: 865 },
+  { p866: 866 },
+  { p867: 867 },
+  { p868: 868 },
+  { p869: 869 },
+  { p870: 870 },
+  { p871: 871 },
+  { p872: 872 },
+  { p873: 873 },
+  { p874: 874 },
+  { p875: 875 },
+  { p876: 876 },
+  { p877: 877 },
+  { p878: 878 },
+  { p879: 879 },
+  { p880: 880 },
+  { p881: 881 },
+  { p882: 882 },
+  { p883: 883 },
+  { p884: 884 },
+  { p885: 885 },
+  { p886: 886 },
+  { p887: 887 },
+  { p888: 888 },
+  { p889: 889 },
+  { p890: 890 },
+  { p891: 891 },
+  { p892: 892 },
+  { p893: 893 },
+  { p894: 894 },
+  { p895: 895 },
+  { p896: 896 },
+  { p897: 897 },
+  { p898: 898 },
+  { p899: 899 },
+  { p900: 900 },
+  { p901: 901 },
+  { p902: 902 },
+  { p903: 903 },
+  { p904: 904 },
+  { p905: 905 },
+  { p906: 906 },
+  { p907: 907 },
+  { p908: 908 },
+  { p909: 909 },
+  { p910: 910 },
+  { p911: 911 },
+  { p912: 912 },
+  { p913: 913 },
+  { p914: 914 },
+  { p915: 915 },
+  { p916: 916 },
+  { p917: 917 },
+  { p918: 918 },
+  { p919: 919 },
+  { p920: 920 },
+  { p921: 921 },
+  { p922: 922 },
+  { p923: 923 },
+  { p924: 924 },
+  { p925: 925 },
+  { p926: 926 },
+  { p927: 927 },
+  { p928: 928 },
+  { p929: 929 },
+  { p930: 930 },
+  { p931: 931 },
+  { p932: 932 },
+  { p933: 933 },
+  { p934: 934 },
+  { p935: 935 },
+  { p936: 936 },
+  { p937: 937 },
+  { p938: 938 },
+  { p939: 939 },
+  { p940: 940 },
+  { p941: 941 },
+  { p942: 942 },
+  { p943: 943 },
+  { p944: 944 },
+  { p945: 945 },
+  { p946: 946 },
+  { p947: 947 },
+  { p948: 948 },
+  { p949: 949 },
+  { p950: 950 },
+  { p951: 951 },
+  { p952: 952 },
+  { p953: 953 },
+  { p954: 954 },
+  { p955: 955 },
+  { p956: 956 },
+  { p957: 957 },
+  { p958: 958 },
+  { p959: 959 },
+  { p960: 960 },
+  { p961: 961 },
+  { p962: 962 },
+  { p963: 963 },
+  { p964: 964 },
+  { p965: 965 },
+  { p966: 966 },
+  { p967: 967 },
+  { p968: 968 },
+  { p969: 969 },
+  { p970: 970 },
+  { p971: 971 },
+  { p972: 972 },
+  { p973: 973 },
+  { p974: 974 },
+  { p975: 975 },
+  { p976: 976 },
+  { p977: 977 },
+  { p978: 978 },
+  { p979: 979 },
+  { p980: 980 },
+  { p981: 981 },
+  { p982: 982 },
+  { p983: 983 },
+  { p984: 984 },
+  { p985: 985 },
+  { p986: 986 },
+  { p987: 987 },
+  { p988: 988 },
+  { p989: 989 },
+  { p990: 990 },
+  { p991: 991 },
+  { p992: 992 },
+  { p993: 993 },
+  { p994: 994 },
+  { p995: 995 },
+  { p996: 996 },
+  { p997: 997 },
+  { p998: 998 },
+  { p999: 999 },
+  { p1000: 1000 },
+  { p1001: 1001 },
+  { p1002: 1002 },
+  { p1003: 1003 },
+  { p1004: 1004 },
+  { p1005: 1005 },
+  { p1006: 1006 },
+  { p1007: 1007 },
+  { p1008: 1008 },
+  { p1009: 1009 },
+  { p1010: 1010 },
+  { p1011: 1011 },
+  { p1012: 1012 },
+  { p1013: 1013 },
+  { p1014: 1014 },
+  { p1015: 1015 },
+  { p1016: 1016 },
+  { p1017: 1017 },
+  { p1018: 1018 },
+  { p1019: 1019 },
+  { p1020: 1020 },
+  { p1021: 1021 },
+  { p1022: 1022 },
+  { p1023: 1023 },
+  { p1024: 1024 },
+  { p1025: 1025 },
+  { p1026: 1026 },
+  { p1027: 1027 },
+  { p1028: 1028 },
+  { p1029: 1029 },
+  { p1030: 1030 },
+  { p1031: 1031 },
+  { p1032: 1032 },
+  { p1033: 1033 },
+  { p1034: 1034 },
+  { p1035: 1035 },
+  { p1036: 1036 },
+  { p1037: 1037 },
+  { p1038: 1038 },
+  { p1039: 1039 },
+  { p1040: 1040 },
+  { p1041: 1041 },
+  { p1042: 1042 },
+  { p1043: 1043 },
+  { p1044: 1044 },
+  { p1045: 1045 },
+  { p1046: 1046 },
+  { p1047: 1047 },
+  { p1048: 1048 },
+  { p1049: 1049 },
+  { p1050: 1050 },
+  { p1051: 1051 },
+  { p1052: 1052 },
+  { p1053: 1053 },
+  { p1054: 1054 },
+  { p1055: 1055 },
+  { p1056: 1056 },
+  { p1057: 1057 },
+  { p1058: 1058 },
+  { p1059: 1059 },
+  { p1060: 1060 },
+  { p1061: 1061 },
+  { p1062: 1062 },
+  { p1063: 1063 },
+  { p1064: 1064 },
+  { p1065: 1065 },
+  { p1066: 1066 },
+  { p1067: 1067 },
+  { p1068: 1068 },
+  { p1069: 1069 },
+  { p1070: 1070 },
+  { p1071: 1071 },
+  { p1072: 1072 },
+  { p1073: 1073 },
+  { p1074: 1074 },
+  { p1075: 1075 },
+  { p1076: 1076 },
+  { p1077: 1077 },
+  { p1078: 1078 },
+  { p1079: 1079 },
+  { p1080: 1080 },
+  { p1081: 1081 },
+  { p1082: 1082 },
+  { p1083: 1083 },
+  { p1084: 1084 },
+  { p1085: 1085 },
+  { p1086: 1086 },
+  { p1087: 1087 },
+  { p1088: 1088 },
+  { p1089: 1089 },
+  { p1090: 1090 },
+  { p1091: 1091 },
+  { p1092: 1092 },
+  { p1093: 1093 },
+  { p1094: 1094 },
+  { p1095: 1095 },
+  { p1096: 1096 },
+  { p1097: 1097 },
+  { p1098: 1098 },
+  { p1099: 1099 },
+];
diff --git a/test-files/test_gap_recur_class_id_unique.ts b/test-files/test_gap_recur_class_id_unique.ts
new file mode 100644
index 0000000000..fbba73d049
--- /dev/null
+++ b/test-files/test_gap_recur_class_id_unique.ts
@@ -0,0 +1,18 @@
+// recur2: generic class specializations must not reuse an object-literal
+// class ID from another module. That collision made the shape claim that
+// Recursor instances inherit Object.prototype and dropped recur on clones.
+import { literals } from "./_helpers/recur_class_id_literals.ts";
+class Recursor<T> {
+  value: T;
+  constructor(value: T) { this.value = value; }
+  recur(n: number): number { return Number(this.value) + n; }
+}
+class Other { recur(n: number): number { return 100 + n; } }
+const original = new Recursor<number>(5);
+const clone = Object.create(Object.getPrototypeOf(original), Object.getOwnPropertyDescriptors(original));
+console.log(literals.length);
+console.log(Object.getPrototypeOf(original) === Recursor.prototype);
+console.log(Object.getPrototypeOf(original) === Object.prototype);
+function invoke(value: any): number { return value.recur(7); }
+console.log(invoke(new Other()));
+console.log(invoke(clone));