no-duplicate-variable: handle parameters

[ajafff]

PR checklist

• Addresses an existing issue: #0000
• New feature, bugfix, or enhancement
  • Includes tests
• Documentation update

Overview of change:

[new-rule-option] no-dupliate-variable adds check-parameters to check if variable has the same name as a parameter

This is needed because of the behavior change of no-shadowed-variable in my upcoming PR.
Also the name of the rule implies this behavior. At least I expected that...

Is there anything you'd like reviewers to focus on?

The rule does not check for duplicate parameter names, because the compiler already does that.

Changelog entry

[new-rule-option] no-duplicate-variable adds check-parameters to check if variable has the same name as a parameter

[adidahiya]

please merge develop, this will fail strict-boolean-expressions #2408

[ajafff]

@adidahiya I can't confirm there is anything failing. Anyways, I rebased on master.

[nchen63]

why isn't y a problem?

[ajafff]

this rule doesn't handle block scoped declarations. these result in a compiler error, so there is no need for a linter error

[adidahiya]

hmm, I dunno about this... parameters do feel a little different from var declarations in the function body, which is why I put this check into no-shadowed-variable... is it really worth the breaking change? can you make the enhancements in #2598 without making this change @ajafff?

[ajafff]

@adidahiya I don't think having this check in no-shadowed-variable is the right thing to do. no-shadowed-variable allows declarations with the same name in the same scope. They either merge (e.g. interface and class) or give a compiler error (e.g. two block scoped variables or block scoped variable and class). Parameters and variables merge if types match, so adding this additional check would be an ugly hack.

How about adding a new config option "check-parameters" to this rule to make it non-breaking?

[ajafff]

@adidahiya I added a new options "check-parameters" to make this change non-breaking