I hit on this old thread when I had the same problem, and later found out something not previously mentioned. Setting

  $^P= 0x100;
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gives you the source line of the eval itself in addition to the line within the eval:

  Use of uninitialized value in print at (eval 1)[./testeval.pl:12] li
+ne 1.
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I found this quite useful for tracking down the offending eval'ed code. See the documentation of $^P / $PERLDB in perlvar for details.