Documentation

Std.Linter.UnnecessarySeqFocus

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opaque Std.Linter.linter.unnecessarySeqFocus :
Lean.Option Bool

Enables the 'unnecessary <;>' linter. This will warn whenever the <;> tactic combinator is used when ; would work.

example : True := by apply id <;> trivial

The <;> is unnecessary here because apply id only makes one subgoal. Prefer apply id; trivial instead.

In some cases, the <;> is syntactically necessary because a single tactic is expected:

example : True := by
  cases () with apply id <;> apply id
  | unit => trivial

In this case, you should use parentheses, as in (apply id; apply id):

example : True := by
  cases () with (apply id; apply id)
  | unit => trivial
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def Std.Linter.UnnecessarySeqFocus.getLinterUnnecessarySeqFocus (o : Lean.Options) :
Bool

Gets the value of the linter.unnecessarySeqFocus option.

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    opaque Std.Linter.UnnecessarySeqFocus.multigoalAttr :
    Lean.TagAttributeExtra

    The multigoal attribute keeps track of tactics that operate on multiple goals, meaning that tac acts differently from focus tac. This is used by the 'unnecessary <;>' linter to prevent false positives where tac <;> tac' cannot be replaced by (tac; tac') because the latter would expose tac to a different set of goals.

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    structure Std.Linter.UnnecessarySeqFocus.Entry :
    Type

    The information we record for each <;> node appearing in the syntax.

    • stx : Lean.Syntax

      The <;> node itself.

    • used : Bool
      • true: this <;> has been used unnecessarily at least once
      • false: it has never been executed
      • If it has been used properly at least once, the entry is removed from the table.
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      @[inline, reducible]
      abbrev Std.Linter.UnnecessarySeqFocus.M (ω : Type) (α : Type) :
      Type

      The monad for collecting used tactic syntaxes.

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        @[inline]
        def Std.Linter.UnnecessarySeqFocus.isSeqFocus (k : Lean.SyntaxNodeKind) :
        Bool

        True if this is a <;> node in either tactic or conv classes.

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          @[specialize #[]]
          partial def Std.Linter.UnnecessarySeqFocus.getTactics {ω : Type} (stx : Lean.Syntax) :
          Std.Linter.UnnecessarySeqFocus.M ω Unit

          Accumulates the set of tactic syntaxes that should be evaluated at least once.

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          def Std.Linter.UnnecessarySeqFocus.getPath :
          Lean.Elab.Info → Lean.PersistentArray Lean.Elab.InfoTree → List ((n : Nat) × Fin n) → Option Lean.Elab.Info

          Traverse the info tree down a given path. Each (n, i) means that the array must have length n and we will descend into the i'th child.

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            partial def Std.Linter.UnnecessarySeqFocus.markUsedTacticsList (env : Lean.Environment) {ω : Type} (trees : Lean.PersistentArray Lean.Elab.InfoTree) :
            Std.Linter.UnnecessarySeqFocus.M ω Unit

            Search for tactic executions in the info tree and remove executed tactic syntaxes.

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            partial def Std.Linter.UnnecessarySeqFocus.markUsedTactics (env : Lean.Environment) {ω : Type} :
            Lean.Elab.InfoTree → Std.Linter.UnnecessarySeqFocus.M ω Unit

            Search for tactic executions in the info tree and remove executed tactic syntaxes.

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            def Std.Linter.UnnecessarySeqFocus.unnecessarySeqFocusLinter :
            Lean.Linter

            The main entry point to the unused tactic linter.

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