Add option to readability-implicit-bool-conversion check to allow implicit conversion *to bool*

[llvmbot]

Bugzilla Link	36975
Version	unspecified
OS	All
Reporter	LLVM Bugzilla Contributor

Extended Description

From the readability-implicit-bool-conversion check, I'd like to take advantage of these parts:

• boolean expression/literal to integer,
• boolean expression/literal to floating.

But not these:

• integer expression/literal to boolean,
• floating expression/literal to boolean,
• pointer/pointer to member/nullptr/NULL to boolean,

Seems like an AllowConversionsToBool option would take care of this. Maybe for completeness/symmetry also a AllowConversionsFromBool option. Both defaulting to 0.

[llvmbot]

@llvm/issue-subscribers-good-first-issue

[PiotrZSL]

As in check both cases are already spited into 2 matchers. then only 2 options need to be added "CheckConversionsToBool", "CheckConversionsFromBool", both set by default to true, and proper testcases should be added (probably exist tests could be split into 2 runs)

[4m4n-x-B4w4ne]

@PiotrZSL, I am new to LLVM and would like to work on this issue. Can you please assign this to me.