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bpo-24612: Improve syntax error for 'not' after an operator #28170

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Merged
encukou merged 4 commits into from
Mar 26, 2024
Merged

bpo-24612: Improve syntax error for 'not' after an operator #28170

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1660f6f
bpo-24612: Improve syntax error for 'not' after an operator
pablogsal Sep 4, 2021
bb6a4c0
Merge in the main branch
encukou Mar 19, 2024
ac6521a
Remove the tilde
encukou Mar 20, 2024
11087c1
Improve syntax error for not after a unary operator
lysnikolaou Mar 21, 2024
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7 changes: 7 additions & 0 deletions Grammar/python.gram
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Original file line number Diff line number Diff line change
Expand Up @@ -778,6 +778,7 @@ bitwise_and[expr_ty]:
shift_expr[expr_ty]:
| a=shift_expr '<<' b=sum { _PyAST_BinOp(a, LShift, b, EXTRA) }
| a=shift_expr '>>' b=sum { _PyAST_BinOp(a, RShift, b, EXTRA) }
| invalid_arithmetic
| sum

# Arithmetic operators
Expand All @@ -794,6 +795,7 @@ term[expr_ty]:
| a=term '//' b=factor { _PyAST_BinOp(a, FloorDiv, b, EXTRA) }
| a=term '%' b=factor { _PyAST_BinOp(a, Mod, b, EXTRA) }
| a=term '@' b=factor { CHECK_VERSION(expr_ty, 5, "The '@' operator is", _PyAST_BinOp(a, MatMult, b, EXTRA)) }
| invalid_factor
| factor

factor[expr_ty] (memo):
Expand Down Expand Up @@ -1415,3 +1417,8 @@ invalid_replacement_field:
invalid_conversion_character:
| '!' &(':' | '}') { RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: missing conversion character") }
| '!' !NAME { RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: invalid conversion character") }

invalid_arithmetic:
| sum ('+'|'-'|'*'|'/'|'%'|'//'|'@') a='not' b=inversion { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "'not' after an operator must be parenthesized") }
invalid_factor:
| ('+' | '-' | '~') a='not' b=factor { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "'not' after an operator must be parenthesized") }
43 changes: 43 additions & 0 deletions Lib/test/test_syntax.py
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Expand Up @@ -1712,6 +1712,49 @@
Traceback (most recent call last):
SyntaxError: only single target (not list) can be annotated

# 'not' after operators:

>>> 3 + not 3
Traceback (most recent call last):
SyntaxError: 'not' after an operator must be parenthesized

>>> 3 * not 3
Traceback (most recent call last):
SyntaxError: 'not' after an operator must be parenthesized

>>> + not 3
Traceback (most recent call last):
SyntaxError: 'not' after an operator must be parenthesized

>>> - not 3
Traceback (most recent call last):
SyntaxError: 'not' after an operator must be parenthesized

>>> ~ not 3
Traceback (most recent call last):
SyntaxError: 'not' after an operator must be parenthesized

>>> 3 + - not 3
Traceback (most recent call last):
SyntaxError: 'not' after an operator must be parenthesized

>>> 3 + not -1
Traceback (most recent call last):
SyntaxError: 'not' after an operator must be parenthesized

# Check that we don't introduce misleading errors
>>> not 1 */ 2
Traceback (most recent call last):
SyntaxError: invalid syntax

>>> not 1 +
Traceback (most recent call last):
SyntaxError: invalid syntax

>>> not + 1 +
Traceback (most recent call last):
SyntaxError: invalid syntax

Corner-cases that used to fail to raise the correct error:

>>> def f(*, x=lambda __debug__:0): pass
Expand Down
2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Core and Builtins/2021-09-04-22-33-01.bpo-24612.SsTuUX.rst
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@@ -0,0 +1,2 @@
Improve the :exc:`SyntaxError` that happens when 'not' appears after an
operator. Patch by Pablo Galindo
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