Hi,
I changed the Python compiler to ignore any kind "constant
expressions", whereas it only ignored strings and integers before:
http://bugs.python.org/issue26204
The compiler now also emits a SyntaxWarning on such case. IMHO the
warning can help to detect bugs for developers who just learnt Python.
The warning is *not* emited for strings, since triple quoted strings
are a common syntax for multiline comments.
The warning is *not* emited neither for ellispis (...) since "f():
..." is a legit syntax for abstract function.
Are you ok with the new warning?
New behaviour:
haypo@smithers$ ./python
Python 3.6.0a0 (default:759a975e1230, Feb 8 2016, 18:21:23)
>>> def f():
... False
...
<stdin>:2: SyntaxWarning: ignore constant statement
>>> import dis; dis.dis(f)
2 0 LOAD_CONST 0 (None)
3 RETURN_VALUE
Old behaviour:
haypo@smithers$ python3
Python 3.4.3 (default, Jun 29 2015, 12:16:01)
>>> def f():
... False
...
>>> import dis; dis.dis(f)
2 0 LOAD_CONST 1 (False)
3 POP_TOP
4 LOAD_CONST 0 (None)
7 RETURN_VALUE
Before strings and numbers were already ignored. Example:
haypo@smithers$ python3
Python 3.4.3 (default, Jun 29 2015, 12:16:01)
>>> def f():
... 123
...
>>> import dis; dis.dis(f)
2 0 LOAD_CONST 0 (None)
3 RETURN_VALUE
Victor
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