Why is this an issue?

A boolean literal can be represented in two different ways: True or False. They can be combined with logical operators (Not, And, Or, =) to produce logical expressions that represent truth values. However, comparing a boolean literal to a variable or expression that evaluates to a boolean value is unnecessary and can make the code harder to read and understand. The more complex a boolean expression is, the harder it will be for developers to understand its meaning and expected behavior, and it will favour the introduction of new bugs.

How to fix it

Remove redundant boolean literals from expressions to improve readability and make the code more maintainable.

Code examples

Noncompliant code example

If BooleanMethod() = True Then ' Noncompliant
  ' ...
End If
If BooleanMethod() = False Then ' Noncompliant
  ' ...
End If
If BooleanMethod() OrElse False Then ' Noncompliant
  ' ...
End If
DoSomething(Not False) ' Noncompliant
DoSomething(BooleanMethod() = True) ' Noncompliant

Dim booleanVariable = If(BooleanMethod(), True, False) ' Noncompliant
booleanVariable = If(BooleanMethod(), True, exp) ' Noncompliant
booleanVariable = If(BooleanMethod(), False, exp) ' Noncompliant
booleanVariable = If(BooleanMethod(), exp, True) ' Noncompliant
booleanVariable = If(BooleanMethod(), exp, False) ' Noncompliant

Compliant solution

If BooleanMethod() Then
  ' ...
End If
If Not BooleanMethod() Then
  ' ...
End If
If BooleanMethod() Then
  ' ...
End If
DoSomething(True)
DoSomething(BooleanMethod())

Dim booleanVariable = BooleanMethod()
booleanVariable = BooleanMethod() OrElse exp
booleanVariable = Not BooleanMethod() AndAlso exp
booleanVariable = Not BooleanMethod() OrElse exp
booleanVariable = BooleanMethod() AndAlso exp