Extend *reportUnnecessaryComparison* to cover ... is True and ... is False

[bram-tv]

Easier to explain with some example code:

# pyright: strict

class Foo:
    pass


foo = Foo()
if foo is None:
    print("foo is None")


if foo is True:
    print("foo is True")

if foo is False:
    print("foo is False")


if foo == None:
    print("foo == None")

if foo == True:
    print("foo == True")

if foo == False:
    print("foo == False")

if foo == 5:
    print("foo == 5")

Output of pyright v1.1.381 (strict):

....py:8:4 - error: Condition will always evaluate to False since the types "Foo" and "None" have no overlap (reportUnnecessaryComparison)
....py:19:4 - error: Condition will always evaluate to False since the types "Foo" and "None" have no overlap (reportUnnecessaryComparison)
....py:22:4 - error: Condition will always evaluate to False since the types "Foo" and "Literal[True]" have no overlap (reportUnnecessaryComparison)
....py:25:4 - error: Condition will always evaluate to False since the types "Foo" and "Literal[False]" have no overlap (reportUnnecessaryComparison)
....py:28:4 - error: Condition will always evaluate to False since the types "Foo" and "Literal[5]" have no overlap (reportUnnecessaryComparison)

Output of mypy v1.11.2 (strict):

....py:12: error: Non-overlapping identity check (left operand type: "Foo", right operand type: "Literal[True]")  [comparison-overlap]
....py:15: error: Non-overlapping identity check (left operand type: "Foo", right operand type: "Literal[False]")  [comparison-overlap]
....py:22: error: Non-overlapping equality check (left operand type: "Foo", right operand type: "Literal[True]")  [comparison-overlap]
....py:25: error: Non-overlapping equality check (left operand type: "Foo", right operand type: "Literal[False]")  [comparison-overlap]
....py:28: error: Non-overlapping equality check (left operand type: "Foo", right operand type: "Literal[5]")  [comparison-overlap]

In short: foo is True and foo is False do not trigger an error in pyright (it does in mypy).

I think that foo is True will always evaluate to False (but maybe I'm missing an edge case?)

[erictraut]

I don't know if x is True is a common source of bugs, but the fact that mypy checks for this case is evidence that someone felt it was enough of an issue to add this check.

I've updated pyright's reportUnnecessaryComparison check accordingly. It now supports all the same cases for is and is not that it previously covered for == and !=. This will be included in the next release.