streamCacheEntry(new ArrayBuffer()).getBuffer.apply(0, [0]);

439       MOZ_ASSERT(cx->isExceptionPending() || cx->isPropagatingForcedReturn() ||
(gdb) bt
#0  AssertExceptionResult (cx=cx@entry=0x7ffff6b39a00) at /home/yksubu/trees/mozilla-central/js/src/vm/Interpreter.cpp:439
#1  0x00005555572df6cf in CallJSNative (cx=cx@entry=0x7ffff6b39a00, native=<optimized out>, reason=reason@entry=js::CallReason::FunCall, args=...) at /home/yksubu/trees/mozilla-central/js/src/vm/Interpreter.cpp:533
#2  0x00005555572b7672 in js::InternalCallOrConstruct (cx=0x7ffff6b39a00, args=..., construct=construct@entry=js::NO_CONSTRUCT, reason=js::CallReason::FunCall) at /home/yksubu/trees/mozilla-central/js/src/vm/Interpreter.cpp:624
#3  0x00005555572b83a8 in InternalCall (cx=<optimized out>, args=..., reason=1490834688, reason@entry=js::CallReason::FunCall) at /home/yksubu/trees/mozilla-central/js/src/vm/Interpreter.cpp:691
#4  0x00005555572b8599 in js::Call (cx=cx@entry=0x7ffff6b39a00, fval=fval@entry=..., thisv=..., args=..., rval=..., reason=reason@entry=js::CallReason::FunCall) at /home/yksubu/trees/mozilla-central/js/src/vm/Interpreter.cpp:723
#5  0x0000555557537fb5 in js::fun_apply (cx=cx@entry=0x7ffff6b39a00, argc=<optimized out>, vp=<optimized out>) at /home/yksubu/trees/mozilla-central/js/src/vm/JSFunction.cpp:1104
#6  0x00005555572df665 in CallJSNative (cx=cx@entry=0x7ffff6b39a00, native=0x555557537ba0 <js::fun_apply(JSContext*, unsigned int, JS::Value*)>, reason=reason@entry=js::CallReason::Call, args=...) at /home/yksubu/trees/mozilla-central/js/src/vm/Interpreter.cpp:528
#7  0x00005555572b7672 in js::InternalCallOrConstruct (cx=0x7ffff6b39a00, args=..., construct=construct@entry=js::NO_CONSTRUCT, reason=js::CallReason::Call) at /home/yksubu/trees/mozilla-central/js/src/vm/Interpreter.cpp:624
/snip

I'm going to guess that this is related to bug 1921780 again.

Run with --fuzzing-safe --no-threads --no-baseline --no-ion, compile with AR=ar sh ../configure --enable-debug --enable-debug-symbols --with-ccache --enable-nspr-build --enable-ctypes --enable-gczeal --enable-rust-simd --disable-tests, tested on m-c rev c71b36339200.

Setting s-s just in case. Jan, did bug 1921780 likely expose the issue?

Set release status flags based on info from the regressing bug 1921780

Just a problem with a testing function.