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The truthiness of an any holding an object is true - #607
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if (a), !a and a ? x : y of an any holding a class instance, an object literal or an array threw "Can't cast from any type": the generated ___unbox<boolean> answered only primitive tags. Every falsy value is a primitive answered there, so what is left is truthy. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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Summary
if (a),!aanda ? x : yon ananyholding a class instance, an object literal or an array threw"Can't cast from any type"at run time ("uncaught exception").The cause: truthiness of an
anygoes through the generated___unbox<boolean>(castPrimitiveTypeFromAny,MLIRGenCast.cpp). It answers primitive tags,nullandundefined, and ended in athrowfor everything else. Every falsy value (0, NaN, "", false, null, undefined, 0n) is a primitive answered there, so for a boolean target the remaining case now returnstrue, as JavaScript does. Every other target type keeps the throw.Found while writing the stack-promotion tests (#605).
Tests
00any_truthiness_objects.tscovers a class instance, an object literal and an array (truthy), plus 0, "" and null (still falsy). It's registered for the default model (JIT and AOT) and in the rc/none corpus. It failed with "uncaught exception" before the fix.🤖 Generated with Claude Code