Incorrect multiplication of number by string

[DartBot]

This issue was originally filed by [email protected]

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What steps will reproduce the problem?

1. Run this one-liner in try.dartlang.org:

  print( 7*'8' );

What is the expected output? What do you see instead?

I would expect an exception due to an object of non-numeric type appearing as the argument to the '*' operator on int/num.

Instead I see the output '56'. I suspect a JavaScript automatic string-to-number coercion is happening where it should not be allowed to.

[DartBot]

This comment was originally written by [email protected]

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Added Area-Compiler, Triaged labels.

[floitschG]

We allow DartC to optimize under the assumption that checked mode would not encounter any AssertionError. Since operator* on num expects a num, checked mode would complain for 7*'8'. The assumptions are hence violated and the behavior thus undefined.
I leave this bug open, in case DartC wants to detect obvious type-errors (like in the example here).

[DartBot]

This comment was originally written by [email protected]

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No more code generation in dartc, so the behavior at runtime should no longer be an issue.

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Added WontFix label.