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Fix validation error in wasm-reduce #8715

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Fix validation error in wasm-reduce #8715

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4c85e84
Fix validation error in wasm-reduce
tlively May 15, 2026
b1a52fa
remove space
tlively May 15, 2026
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3 changes: 2 additions & 1 deletion src/tools/wasm-reduce/wasm-reduce.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1102,6 +1102,7 @@ struct Reducer
auto* block =
ChildLocalizer(curr, getFunction(), *getModule(), getPassOptions())
.getChildrenReplacement();
auto originalType = curr->type;
auto* replacement = builder.replaceWithIdenticalType(curr);
// We may have failed to come up with a replacement (e.g. for
// non-nullable references), so manually add an `unreachable` in that
Expand All @@ -1110,7 +1111,7 @@ struct Reducer
replacement = builder.makeUnreachable();
}
block->list.push_back(replacement);
block->type = curr->type;
block->type = originalType;
replaceCurrent(block);
}
void visitRefFunc(RefFunc* curr) {
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19 changes: 19 additions & 0 deletions test/lit/wasm-reduce/reduce-validation-error.wast
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Original file line number Diff line number Diff line change
@@ -0,0 +1,19 @@
;; This is a regression test for a crash in wasm-reduce where in-place mutation
;; of a Call node during replaceWithIdenticalType caused the replacement block
;; type to be set incorrectly to nullref instead of the original type, leading
;; to a validation error.

;; RUN: wasm-reduce %s -t %t.t.wast -w %t.w.wast \
;; RUN: --command='wasm-opt %t.t.wast -all --fuzz-exec'

(module
(func $to_remove (result anyref)
(ref.null none)
)

(func $main (export "main") (result anyref)
;; This will be replaced with a nullref. This should not cause validation
;; failures and cause wasm-reduce to crash.
(call $to_remove)
)
)
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