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Fix Unsubtyping on extern.convert_any #8062

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Merged
tlively merged 1 commit into from
Nov 19, 2025
Merged

Fix Unsubtyping on extern.convert_any #8062

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15 changes: 13 additions & 2 deletions src/ir/subtype-exprs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -445,8 +445,19 @@ struct SubtypingDiscoverer : public OverriddenVisitor<SubType> {
self()->noteSubtype(curr->replacement, type);
}
void visitRefAs(RefAs* curr) {
if (curr->op == RefAsNonNull) {
self()->noteCast(curr->value, curr);
switch (curr->op) {
case RefAsNonNull:
self()->noteCast(curr->value, curr);
return;
case AnyConvertExtern:
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@kripken kripken Nov 19, 2025

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Doesn't this require extern?

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@tlively tlively Nov 19, 2025

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In principle, yes, but extern has no defined subtypes, so in practice (for Unsubtyping, at least) it doesn't matter.

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@kripken kripken Nov 20, 2025

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Right, I guess it doesn't make a difference...

return;
case ExternConvertAny:
if (curr->type != Type::unreachable) {
auto any =
HeapTypes::any.getBasic(curr->type.getHeapType().getShared());
self()->noteSubtype(curr->value, Type(any, Nullable));
}
return;
}
}
void visitStringNew(StringNew* curr) {}
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82 changes: 82 additions & 0 deletions test/lit/passes/unsubtyping.wast
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Expand Up @@ -1920,3 +1920,85 @@
)
)
)

;; extern.convert_any requires its input to remain a subtype of any.
(module
;; CHECK: (rec
;; CHECK-NEXT: (type $A (sub (struct)))
(type $A (sub (struct)))
;; CHECK: (type $B (sub $A (struct)))
(type $B (sub $A (struct)))

;; CHECK: (type $2 (func (result externref)))

;; CHECK: (type $3 (func (param anyref)))

;; CHECK: (func $test (type $2) (result externref)
;; CHECK-NEXT: (extern.convert_any
;; CHECK-NEXT: (struct.new_default $B)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $test (result externref)
(extern.convert_any
(struct.new $B)
)
)

;; CHECK: (func $cast (type $3) (param $0 anyref)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (ref.cast (ref null $A)
;; CHECK-NEXT: (local.get $0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $cast (param anyref)
(drop
;; Since $B flows into any, it must remain a subtype of $A to continue
;; passing this cast.
(ref.cast (ref null $A)
(local.get 0)
)
)
)
)

;; Same as above with shared types.
(module
;; CHECK: (rec
;; CHECK-NEXT: (type $A (sub (shared (struct))))
(type $A (sub (shared (struct))))
;; CHECK: (type $B (sub $A (shared (struct))))
(type $B (sub $A (shared (struct))))

;; CHECK: (type $2 (func (result (ref null (shared extern)))))

;; CHECK: (type $3 (func (param (ref null (shared any)))))

;; CHECK: (func $test (type $2) (result (ref null (shared extern)))
;; CHECK-NEXT: (extern.convert_any
;; CHECK-NEXT: (struct.new_default $B)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $test (result (ref null (shared extern)))
(extern.convert_any
(struct.new $B)
)
)

;; CHECK: (func $cast (type $3) (param $0 (ref null (shared any)))
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (ref.cast (ref null $A)
;; CHECK-NEXT: (local.get $0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $cast (param (ref null (shared any)))
(drop
;; Since $B flows into any, it must remain a subtype of $A to continue
;; passing this cast.
(ref.cast (ref null $A)
(local.get 0)
)
)
)
)
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