dynamic `new <class-value>(args)` drops all args when the class has an implicit default constructor — every effect error loses its message

[proggeramlug]

Summary

A function-nested class extending an Error-descendant, with no explicit constructor, drops the arguments passed to new — the implicit derived constructor fails to forward them to super(...). Every error built through effect's makeException factory therefore has message === undefined, and every failure in an effect app prints as "An error has occurred" instead of its real message (e.g. the web.ts startup failure surfaces as a message-less RuntimeException, hiding whatever dieMessage(...) text node would show).

Minimal repro

class Y extends Error {}

const make2 = (): any => {
  class Plain extends Y {}          // no captures, no statics, no ctor
  return Plain
}
const P2 = make2()
console.log(new P2("direct").message)   // node: "direct" | perry: undefined

Matrix (probe40, node → perry)

case	node	perry
implicit ctor, nested class w/ captured field (new A("boom"))	"boom"	undefined
implicit ctor, nested class, no captures (new P2("direct"))	"direct"	undefined
implicit ctor, class expression w/ capture (new C3("expr-msg"))	"expr-msg"	undefined
explicit constructor(msg?){ super(msg) } + capture	"explicit"	"explicit" ✓

The explicit-forwarding case works, so the defect is specifically the synthesized default derived constructor (spec: constructor(...args) { super(...args) }) not forwarding args — at least for classes whose base chain reaches the native Error.

Impact

• effect's makeException classes (RuntimeException, InterruptedException, TimeoutException, …) all lose their message: Cause.pretty renders "An error has occurred" for every failure, destroying diagnosability of any effect app under perry.
• Blocks byte-parity of effect-compiled-experiment web.ts (the remaining app of the 4; discovered after fix(hir): per-evaluation statics for class expressions with heritage (#6438) #6449 → fix(runtime): resolve [Symbol.iterator] on a class declaration (#6454) #6460 → module init: nested dep-init calls ignore the topo sort's cycle-breaks — alias exports capture undefined (FindMyWay.make undefined; blocks effect web.ts) #6463 → class declarations in function bodies share one class across evaluations — effect's makeException masks every error as TimeoutException #6465 layers).

Found while unmasking the web.ts startup failure: with the #6465 per-evaluation fix applied, the real error is a RuntimeException whose message was dropped by this bug — the actual failure text is still unknown until this is fixed.

[proggeramlug]

Sharper diagnosis — the axis is DYNAMIC construction, not nested-ness

probe42 (module-top classes only):

class Top extends Error {}
class Mid extends Top {}
const K: any = Mid
new K("dyn-top").message        // node: "dyn-top"  | perry: undefined   ← dynamic, implicit ctor
new Mid("stat-top").message     // node: "stat-top" | perry: "stat-top"  ← static, same class
function get(): any { return Mid }
new (get())("via-fn").message   // node: "via-fn"   | perry: undefined   ← dynamic, implicit ctor
class Fwd extends Error { constructor(m?: string) { super(m) } }
const F: any = Fwd
new F("dyn-fwd").message        // node: "dyn-fwd"  | perry: "dyn-fwd"   ← dynamic, EXPLICIT ctor

new <class-value>(args) where the class has an implicit (spec-default) constructor drops every user argument. Static new Mid(...) forwards fine; an explicit forwarding ctor makes the dynamic path work too. So the runtime dynamic-construct dispatch only threads user args through a registered constructor function — the implicit-ctor fallback allocates and runs the ancestor chain without them, so Error.message (and any ancestor ctor behavior) never sees the args.

Nested classes and captures (the original report) are just the common way a class value gets constructed dynamically — the factory return Base forces every new through the dynamic path.

This also explains why the effect symptom is universal: makeException classes have no explicit ctor, and every construction site (new RuntimeException(message)) is dynamic (the class is a value returned from the factory).