Code Inspection: Expression is always 'true' or always 'false'

This inspection is fairly obvious: ReSharper analyzes values and nullability of symbols and suggests to eliminate expressions that are always true or always false.

The only problem with this inspection is that sometimes it's not obvious how ReSharper has come to this conclusion. Because of this, you may be unwilling to accept the ReSharper’s suggestion to replace an expression with explicit true or false, or to remove a redundant check in an if statement. Below are some StackOverflow questions that illustrate this problem:

• Why does ReSharper tell me this expression is always true?

• How Does ReSharper Know “Expression is always true”?

• ReSharper bug? Incorrect “expression is always true”

• ReSharper claims that my expression is always true? Is it correct or is it a bug?

• ReSharper says this expression is always true. Why?

• Trying to understand why resharper told me expression is always false

• Why I getting an “Expression always true” warning?