Igor, can you take a look? Looks like a failure in Crankshaft.

I can reproduce this in a regular x64.debug with the attached file (from the clusterfuzz issue)

Deleted: mutant20736_array-concat-object-proto-dict.js 2.1 KB

mutant20736_array-concat-object-proto-dict.js 2.1 KB View Download

ClusterFuzz has detected this issue as fixed in range 40170:40171.

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=6535067449163776

Fuzzer: decoder_langfuzz
Job Type: linux_asan_d8
Platform Id: linux

Crash Type: UNKNOWN READ
Crash Address: 0x000000000000
Crash State:
  v8::internal::Map::instance_type
  v8::internal::AstType::NowOf
  v8::internal::AstTyper::ObservedOnStack
  
Regressed: V8: r40152:40153
Fixed: V8: r40170:40171

Minimized Testcase (7.55 Kb): https://cluster-fuzz.appspot.com/download/AMIfv9725TT8gV-wrgnUQPNnKUFyugmsB6xxkT_U5PATafYbRUEq2EB9bVPe3mkQul_xtWu7_5ouLq-iHmORglnK4Gv0NRy8WyQmq75qVSVEHpUKv2CqrfNEMRFf3HnbKZRAW-o1KuKhj0yQRs3wZSeVMvCw_DpiMQ?testcase_id=6535067449163776

See https://dev.chromium.org/Home/chromium-security/bugs/reproducing-clusterfuzz-bugs for more information.

If you suspect that the result above is incorrect, try re-doing that job on the test case report page.

ClusterFuzz testcase is verified as fixed, closing issue.

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