rules:
  - id: error-shadow-check-types 
    patterns:
        - pattern: |
            ..., ($ERR: error) = $FUNC(...)
            ...
            ..., $ERR = ...
        - pattern-not: |
            ..., ($ERR: error) = $FUNC(...)
            ...
            if <... $ERR == nil ...> {
                ...
            }
            ...
            ..., $ERR = ...
        - pattern-not: |
            ..., ($ERR: error) = $FUNC(...)
            ...
            if <... $ERR != nil ...> {
                ...
            }
            ...
            ..., $ERR = ...
        - pattern-not: |
            ..., ($ERR: error) = $FUNC(...)
            ...
            $ERRCHECK(..., $ERR, ...)
            ...
            ..., $ERR = ...
        # This case is not specific enough but semgrep doesn't let you do any
        # special searching within a switch statement. We will assume if there
        # is a switch statement it's doing error checking, though this isn't
        # guaranteed.
        - pattern-not: |
            ..., ($ERR: error) = $FUNC(...)
            ...
            switch {
            case ...
            }
            ...
            ..., $ERR = ...
    message: Potential Error Shadowing
    languages:
      - go
    severity: ERROR


  - id: error-shadow-check-regex 
    patterns:
        - pattern: |
            ..., $ERR = $FUNC(...)
            ...
            ..., $ERR = ...
        - pattern-not: |
            ..., $ERR = $FUNC(...)
            ...
            if <... $ERR == nil ...> {
                ...
            }
            ...
            ..., $ERR = ...
        - pattern-not: |
            ..., $ERR = $FUNC(...)
            ...
            if <... $ERR != nil ...> {
                ...
            }
            ...
            ..., $ERR = ...
        - pattern-not: |
            ..., $ERR = $FUNC(...)
            ...
            $ERRCHECK(..., $ERR, ...)
            ...
            ..., $ERR = ...

        # This pattern is used in as a itteration mechanism for a test
        - pattern-not: |
            ..., $ERR = $FUNC(...)
            ...
            for $ERR == nil {
                ...
            }
            ...
            ..., $ERR = ...

        # A few places we test against logical.Err* types
        - pattern-not: |
            ..., $ERR = $FUNC(...)
            ...
            if $ERR != logical.$ERRTYPE {
                ...
            }
            ...
            ..., $ERR = ...
        # This case is not specific enough but semgrep doesn't let you do any
        # special searching within a switch statement. We will assume if there
        # is a switch statement it's doing error checking, though this isn't
        # guaranteed.
        - pattern-not: |
            ..., $ERR = $FUNC(...)
            ...
            switch ... {
            case ...
            }
            ...
            ..., $ERR = ...
        - pattern-not: |
            ..., $ERR = $FUNC(...)
            ...
            switch {
            case ...
            }
            ...
            ..., $ERR = ...
        - metavariable-regex:
              metavariable: $ERR
              regex: "err"
    message: Potential Error Shadowing (regex)
    languages:
      - go
    severity: ERROR