Fix class expression super() bytecode crash in decorator wrapping benchmark

[frostney]

Fix a fatal error in bytecode mode for class expressions extending dynamic values with super() calls.

The CompileClassExpression incorrectly used AllocateRegister() for the super register, preventing __super__ from being resolved via upvalue capture in constructors, leading to a crash and the "class decorator (wrapping)" benchmark reporting 0 ops/sec.

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Summary by CodeRabbit

Release Notes

• Tests

  • Added comprehensive test suite for class expressions extending dynamic base classes, covering constructor super() calls, argument spreading, implicit super behavior, method inheritance patterns, and decorator-like wrapping functionality for enhanced validation.

• Refactor

  • Optimized internal storage mechanism for superclass references in class declarations and expressions to improve memory efficiency without affecting external behavior.

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[coderabbitai]

📝 Walkthrough

Walkthrough

A new test suite validates class expressions extending dynamic bases with various inheritance patterns, including constructor super() calls, spread arguments, implicit super behavior, additional methods, and decorator wrapping. The compiler's superclass reference handling is modified to use a dedicated local variable slot instead of a temporary register.

Changes

Cohort / File(s)	Summary
Test Suite for Class Extension tests/language/classes/class-expression-extends.js	New test file (+99 lines) covering class expression inheritance patterns: explicit super() calls, spread arguments to super, implicit super without constructor, extended methods, and decorator-like constructor wrapping with instanceof and property propagation validation.
Compiler Superclass Reference Handling units/Goccia.Compiler.Statements.pas	Changed superclass reference storage from a temporary allocated register to a dedicated local variable slot named __super__. Affects both class expression and class declaration paths; subsequent inheritance setup operations (move, get_upvalue/get_global, inherit, set wrapped super) now target the local slot instead of the transient register.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~15 minutes

Poem

🐰 Classes now extend with grace so fine,
A local __super__ slot so divine,
From registers freed, the inheritance flows,
While tests bloom bright in delightful rows! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Title check	✅ Passed	The PR title accurately reflects the main fix: addressing a bytecode crash in class expression super() calls that occurs in decorator wrapping scenarios.

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✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch cursor/class-wrapping-benchmark-issue-065c

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Benchmark Results

254 benchmarks (no baseline)

arraybuffer.js — 14 benchmarks

Benchmark	Interpreted	Bytecode
create ArrayBuffer(0)	391,249	141,135
create ArrayBuffer(64)	396,022	145,321
create ArrayBuffer(1024)	310,378	127,155
create ArrayBuffer(8192)	136,358	82,409
slice full buffer (64 bytes)	477,189	366,010
slice half buffer (512 of 1024 bytes)	403,123	330,022
slice with negative indices	404,345	359,906
slice empty range	461,145	372,050
byteLength access	1,476,392	1,065,450
Symbol.toStringTag access	1,087,835	518,142
ArrayBuffer.isView	692,347	463,968
clone ArrayBuffer(64)	358,411	313,313
clone ArrayBuffer(1024)	277,637	247,764
clone ArrayBuffer inside object	236,109	152,676

arrays.js — 19 benchmarks

Benchmark	Interpreted	Bytecode
Array.from length 100	13,666	12,941
Array.from 10 elements	218,927	158,294
Array.of 10 elements	292,100	223,508
spread into new array	310,693	533,443
map over 50 elements	25,842	22,238
filter over 50 elements	22,216	21,460
reduce sum 50 elements	25,472	19,541
forEach over 50 elements	21,576	22,988
find in 50 elements	32,890	27,812
sort 20 elements	11,254	3,371
flat nested array	103,183	249,681
flatMap	64,586	182,933
map inside map (5x5)	18,793	65,383
filter inside map (5x10)	13,676	13,313
reduce inside map (5x10)	16,669	13,531
forEach inside forEach (5x10)	14,449	15,084
find inside some (10x10)	11,688	10,635
map+filter chain nested (5x20)	4,628	4,439
reduce flatten (10x5)	31,536	4,599

async-await.js — 6 benchmarks

Benchmark	Interpreted	Bytecode
single await	313,121	227,621
multiple awaits	142,232	97,628
await non-Promise value	685,894	643,548
await with try/catch	308,474	225,324
await Promise.all	44,206	39,300
nested async function call	158,058	172,582

classes.js — 31 benchmarks

Benchmark	Interpreted	Bytecode
simple class new	110,845	354,341
class with defaults	88,647	236,484
50 instances via Array.from	5,237	6,286
instance method call	53,857	158,283
static method call	84,141	375,420
single-level inheritance	41,882	145,150
two-level inheritance	35,093	126,398
private field access	53,107	173,057
private methods	56,317	215,594
getter/setter access	58,106	172,614
class decorator (identity)	71,857	52,526
class decorator (wrapping)	41,999	36,191
identity method decorator	52,573	43,035
wrapping method decorator	42,755	39,241
stacked method decorators (x3)	29,915	27,457
identity field decorator	56,454	45,123
field initializer decorator	47,465	39,672
getter decorator (identity)	49,221	39,885
setter decorator (identity)	40,793	34,817
static method decorator	51,837	61,294
static field decorator	61,238	64,466
private method decorator	39,733	36,557
private field decorator	42,524	37,820
plain auto-accessor (no decorator)	76,906	52,130
auto-accessor with decorator	45,342	36,123
decorator writing metadata	36,165	40,228
static getter read	85,384	387,278
static getter/setter pair	66,113	201,440
inherited static getter	51,398	261,827
inherited static setter	52,946	201,948
inherited static getter with this binding	45,224	151,242

closures.js — 11 benchmarks

Benchmark	Interpreted	Bytecode
closure over single variable	101,045	580,177
closure over multiple variables	96,169	377,169
nested closures	98,403	526,138
function as argument	78,651	500,551
function returning function	92,488	574,847
compose two functions	57,426	355,333
fn.call	125,750	133,419
fn.apply	92,909	87,636
fn.bind	109,185	144,950
recursive sum to 50	10,310	38,451
recursive tree traversal	16,561	59,296

collections.js — 12 benchmarks

Benchmark	Interpreted	Bytecode
add 50 elements	6,552	5,708
has lookup (50 elements)	89,340	89,260
delete elements	45,585	38,021
forEach iteration	13,447	15,590
spread to array	22,826	32,091
deduplicate array	33,392	32,713
set 50 entries	4,849	5,919
get lookup (50 entries)	86,799	102,624
has check	127,204	161,776
delete entries	45,632	36,410
forEach iteration	12,977	15,470
keys/values/entries	6,244	8,398

destructuring.js — 22 benchmarks

Benchmark	Interpreted	Bytecode
simple array destructuring	319,054	616,186
with rest element	215,385	461,135
with defaults	330,960	645,161
skip elements	343,160	680,457
nested array destructuring	132,676	320,900
swap variables	385,467	956,979
simple object destructuring	251,367	519,824
with defaults	296,387	324,395
with renaming	262,770	574,050
nested object destructuring	119,621	248,817
rest properties	156,569	225,022
object parameter	75,112	182,063
array parameter	97,055	311,549
mixed destructuring in map	29,830	34,569
forEach with array destructuring	50,412	129,646
map with array destructuring	50,191	154,364
filter with array destructuring	53,776	179,052
reduce with array destructuring	55,851	173,805
map with object destructuring	62,723	72,981
map with nested destructuring	53,592	60,313
map with rest in destructuring	28,470	47,538
map with defaults in destructuring	48,980	39,231

fibonacci.js — 8 benchmarks

Benchmark	Interpreted	Bytecode
recursive fib(15)	268	1,136
recursive fib(20)	26	103
recursive fib(15) typed	274	1,441
recursive fib(20) typed	26	131
iterative fib(20) via reduce	9,550	17,155
iterator fib(20)	7,618	11,107
iterator fib(20) via Iterator.from + take	7,209	10,635
iterator fib(20) last value via reduce	6,192	8,995

for-of.js — 7 benchmarks

Benchmark	Interpreted	Bytecode
for...of with 10-element array	37,914	59,233
for...of with 100-element array	4,279	7,488
for...of with string (10 chars)	27,435	54,900
for...of with Set (10 elements)	38,575	60,816
for...of with Map entries (10 entries)	22,604	11,981
for...of with destructuring	31,867	51,814
for-await-of with sync array	36,051	47,837

iterators.js — 20 benchmarks

Benchmark	Interpreted	Bytecode
Iterator.from({next}).toArray() — 20 elements	8,735	12,088
Iterator.from({next}).toArray() — 50 elements	3,808	5,073
spread pre-wrapped iterator — 20 elements	8,796	11,646
Iterator.from({next}).forEach — 50 elements	2,940	4,117
Iterator.from({next}).reduce — 50 elements	2,951	3,873
wrap array iterator	45,441	57,451
wrap plain {next()} object	6,198	9,520
map + toArray (50 elements)	2,500	3,435
filter + toArray (50 elements)	2,657	3,807
take(10) + toArray (50 element source)	13,469	18,871
drop(40) + toArray (50 element source)	3,720	5,165
chained map + filter + take (100 element source)	4,341	5,823
some + every (50 elements)	1,706	2,477
find (50 elements)	3,661	5,193
array.values().map().filter().toArray()	2,997	4,902
array.values().take(5).toArray()	47,927	65,510
array.values().drop(45).toArray()	12,878	25,222
map.entries() chained helpers	4,566	2,671
set.values() chained helpers	7,159	10,828
string iterator map + toArray	5,809	9,691

json.js — 20 benchmarks

Benchmark	Interpreted	Bytecode
parse simple object	141,532	129,121
parse nested object	83,281	82,265
parse array of objects	45,930	49,527
parse large flat object	44,020	47,282
parse mixed types	60,532	67,424
stringify simple object	134,381	130,772
stringify nested object	70,953	69,086
stringify array of objects	37,785	35,732
stringify mixed types	61,870	58,651
reviver doubles numbers	36,915	44,414
reviver filters properties	32,350	45,976
reviver on nested object	41,301	51,837
reviver on array	24,064	29,366
replacer function doubles numbers	37,335	48,601
replacer function excludes properties	48,557	57,572
array replacer (allowlist)	90,807	94,363
stringify with 2-space indent	70,256	68,757
stringify with tab indent	71,134	65,765
parse then stringify	40,493	44,795
stringify then parse	25,047	27,375

jsx.jsx — 21 benchmarks

Benchmark	Interpreted	Bytecode
simple element	152,018	588,488
self-closing element	158,915	615,628
element with string attribute	130,684	418,268
element with multiple attributes	111,767	365,470
element with expression attribute	119,862	426,230
text child	150,905	598,131
expression child	147,013	533,388
mixed text and expression	146,765	493,598
nested elements (3 levels)	58,821	230,949
sibling children	42,869	174,003
component element	107,059	421,312
component with children	65,153	261,290
dotted component	87,753	314,435
empty fragment	160,094	630,268
fragment with children	44,018	175,065
spread attributes	86,576	105,388
spread with overrides	73,799	78,193
shorthand props	120,978	408,730
nav bar structure	20,220	78,762
card component tree	24,251	85,078
10 list items via Array.from	10,937	23,168

numbers.js — 11 benchmarks

Benchmark	Interpreted	Bytecode
integer arithmetic	463,697	1,470,733
floating point arithmetic	475,076	1,577,223
number coercion	163,234	133,322
toFixed	87,291	211,930
toString	126,963	654,046
valueOf	169,711	923,397
toPrecision	115,753	393,925
Number.isNaN	258,710	174,425
Number.isFinite	255,398	169,154
Number.isInteger	253,175	186,228
Number.parseInt and parseFloat	212,711	148,943

objects.js — 7 benchmarks

Benchmark	Interpreted	Bytecode
create simple object	364,512	839,753
create nested object	181,819	372,726
create 50 objects via Array.from	7,911	8,163
property read	521,945	657,552
Object.keys	240,708	203,100
Object.entries	79,134	64,928
spread operator	155,324	210,680

promises.js — 12 benchmarks

Benchmark	Interpreted	Bytecode
Promise.resolve(value)	393,647	345,574
new Promise(resolve => resolve(value))	149,807	163,775
Promise.reject(reason)	392,152	330,587
resolve + then (1 handler)	121,133	124,216
resolve + then chain (3 deep)	46,175	56,172
resolve + then chain (10 deep)	14,463	19,087
reject + catch + then	65,049	75,460
resolve + finally + then	53,569	62,550
Promise.all (5 resolved)	20,940	26,596
Promise.race (5 resolved)	22,152	27,980
Promise.allSettled (5 mixed)	17,521	22,798
Promise.any (5 mixed)	20,588	26,121

strings.js — 11 benchmarks

Benchmark	Interpreted	Bytecode
string concatenation	327,699	400,460
template literal	355,360	679,848
string repeat	326,885	982,727
split and join	110,569	231,492
indexOf and includes	129,128	549,184
toUpperCase and toLowerCase	196,905	685,221
slice and substring	130,428	622,096
trim operations	145,274	720,357
replace and replaceAll	168,056	603,982
startsWith and endsWith	106,453	482,355
padStart and padEnd	171,903	554,562

typed-arrays.js — 22 benchmarks

Benchmark	Interpreted	Bytecode
new Int32Array(0)	247,611	132,008
new Int32Array(100)	225,183	126,981
new Int32Array(1000)	151,822	73,635
new Float64Array(100)	230,408	128,823
Int32Array.from([...])	153,109	59,102
Int32Array.of(1, 2, 3, 4, 5)	252,141	247,524
sequential write 100 elements	3,013	6,551
sequential read 100 elements	3,093	5,830
Float64Array write 100 elements	2,949	6,432
fill(42)	46,611	45,552
slice()	188,709	200,528
map(x => x * 2)	6,741	7,271
filter(x => x > 50)	6,965	7,862
reduce (sum)	6,723	6,328
sort()	166,198	156,865
indexOf()	390,151	360,074
reverse()	305,157	273,013
create view over existing buffer	319,119	140,714
subarray()	365,625	366,934
set() from array	497,315	240,472
for-of loop	4,116	8,049
spread into array	13,688	19,134

_{Measured on ubuntu-latest x64. Changes within ±7% are considered insignificant.}

[coderabbitai]

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

units/Goccia.Compiler.Statements.pas (1)

1903-1906: ⚠️ Potential issue | 🟠 Major

Remove stale FreeRegister call for SuperReg.

Line 1906 calls FreeRegister for SuperReg, but this is incorrect now that SuperReg is allocated via DeclareLocal (line 1806) rather than AllocateRegister. Locals declared with DeclareLocal are managed by the scope system and freed via EndScope, not FreeRegister.

Compare with CompileClassDeclaration (lines 1757-1760) which does not call FreeRegister for its SuperReg.

🐛 Proposed fix: remove the FreeRegister call

   if HasSuper then
-  begin
-    CompileDecoratorAndAccessorPass(ACtx, ADest, ClassDef, SuperReg);
-    ACtx.Scope.FreeRegister;
-  end
+    CompileDecoratorAndAccessorPass(ACtx, ADest, ClassDef, SuperReg)
   else
     CompileDecoratorAndAccessorPass(ACtx, ADest, ClassDef, -1);

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@units/Goccia.Compiler.Statements.pas` around lines 1903 - 1906, The call
ACtx.Scope.FreeRegister after CompileDecoratorAndAccessorPass should be removed
because SuperReg is now created via DeclareLocal (not AllocateRegister) and is
managed by the scope system; locate the HasSuper branch in
CompileDecoratorAndAccessorPass/CompileClassDeclaration where SuperReg is used
and delete the ACtx.Scope.FreeRegister invocation so SuperReg is freed via
EndScope like other locals.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Outside diff comments:
In `@units/Goccia.Compiler.Statements.pas`:
- Around line 1903-1906: The call ACtx.Scope.FreeRegister after
CompileDecoratorAndAccessorPass should be removed because SuperReg is now
created via DeclareLocal (not AllocateRegister) and is managed by the scope
system; locate the HasSuper branch in
CompileDecoratorAndAccessorPass/CompileClassDeclaration where SuperReg is used
and delete the ACtx.Scope.FreeRegister invocation so SuperReg is freed via
EndScope like other locals.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 44c0e38b-33bb-4588-b008-31b3d23c5043

📥 Commits

Reviewing files that changed from the base of the PR and between 1755a05 and 03a9b3f.

📒 Files selected for processing (2)

• tests/language/classes/class-expression-extends.js
• units/Goccia.Compiler.Statements.pas