ce73bbe277
When the `decide` tactic fails, it can try to give hints about the failure: - It tells you which `Decidable` instances it unfolded, by making use of the diagnostics feature. - If it encounters `Eq.rec`, it gives you a hint that one of these instances was likely defined using tactics. - If it encounters `Classical.choice`, it hints that you might have classical instances in scope. - During this, it tries to process `Decidable.rec`s and matchers to pin blame on a particular instance that failed to reduce. This idea comes from discussion with Heather Macbeth [on Zulip](https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/Decidable.20with.20structures/near/449409870).
163 lines
6.8 KiB
Text
163 lines
6.8 KiB
Text
/-
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Copyright (c) 2020 Sebastian Ullrich. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Sebastian Ullrich
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-/
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prelude
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import Lean.PrettyPrinter.Delaborator
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import Lean.PrettyPrinter.Parenthesizer
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import Lean.PrettyPrinter.Formatter
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import Lean.Parser.Module
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import Lean.ParserCompiler
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namespace Lean
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def PPContext.runCoreM {α : Type} (ppCtx : PPContext) (x : CoreM α) : IO α :=
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Prod.fst <$> x.toIO { options := ppCtx.opts, currNamespace := ppCtx.currNamespace
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openDecls := ppCtx.openDecls
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fileName := "<PrettyPrinter>", fileMap := default
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diag := getDiag ppCtx.opts }
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{ env := ppCtx.env, ngen := { namePrefix := `_pp_uniq } }
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def PPContext.runMetaM {α : Type} (ppCtx : PPContext) (x : MetaM α) : IO α :=
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ppCtx.runCoreM <| x.run' { lctx := ppCtx.lctx } { mctx := ppCtx.mctx }
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namespace PrettyPrinter
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def ppCategory (cat : Name) (stx : Syntax) : CoreM Format := do
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let opts ← getOptions
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let stx := (sanitizeSyntax stx).run' { options := opts }
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parenthesizeCategory cat stx >>= formatCategory cat
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def ppTerm (stx : Term) : CoreM Format := ppCategory `term stx
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def ppUsing (e : Expr) (delab : Expr → MetaM Term) : MetaM Format := do
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let lctx := (← getLCtx).sanitizeNames.run' { options := (← getOptions) }
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Meta.withLCtx lctx #[] do
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ppTerm (← delab e)
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def ppExpr (e : Expr) : MetaM Format := do
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ppUsing e delab
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/-- Return a `fmt` representing pretty-printed `e` together with a map from tags in `fmt`
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to `Elab.Info` nodes produced by the delaborator at various subexpressions of `e`. -/
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def ppExprWithInfos (e : Expr) (optsPerPos : Delaborator.OptionsPerPos := {}) (delab := Delaborator.delab)
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: MetaM FormatWithInfos := do
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let lctx := (← getLCtx).sanitizeNames.run' { options := (← getOptions) }
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Meta.withLCtx lctx #[] do
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let (stx, infos) ← delabCore e optsPerPos delab
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let fmt ← ppTerm stx
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return ⟨fmt, infos⟩
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@[export lean_pp_expr]
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def ppExprLegacy (env : Environment) (mctx : MetavarContext) (lctx : LocalContext) (opts : Options) (e : Expr) : IO Format :=
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Prod.fst <$> ((withOptions (fun _ => opts) <| ppExpr e).run' { lctx := lctx } { mctx := mctx }).toIO
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{ fileName := "<PrettyPrinter>", fileMap := default }
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{ env := env }
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def ppTactic (stx : TSyntax `tactic) : CoreM Format := ppCategory `tactic stx
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def ppCommand (stx : Syntax.Command) : CoreM Format := ppCategory `command stx
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def ppModule (stx : TSyntax ``Parser.Module.module) : CoreM Format := do
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parenthesize Lean.Parser.Module.module.parenthesizer stx >>= format Lean.Parser.Module.module.formatter
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open Delaborator in
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/-- Pretty-prints a declaration `c` as `c.{<levels>} <params> : <type>`. -/
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def ppSignature (c : Name) : MetaM FormatWithInfos := do
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let decl ← getConstInfo c
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let e := .const c (decl.levelParams.map mkLevelParam)
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let (stx, infos) ← delabCore e (delab := delabConstWithSignature)
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return ⟨← ppTerm ⟨stx⟩, infos⟩ -- HACK: not a term
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private partial def noContext : MessageData → MessageData
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| MessageData.withContext _ msg => noContext msg
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| MessageData.withNamingContext ctx msg => MessageData.withNamingContext ctx (noContext msg)
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| MessageData.nest n msg => MessageData.nest n (noContext msg)
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| MessageData.group msg => MessageData.group (noContext msg)
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| MessageData.compose msg₁ msg₂ => MessageData.compose (noContext msg₁) (noContext msg₂)
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| MessageData.tagged tag msg => MessageData.tagged tag (noContext msg)
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| MessageData.trace data header children =>
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MessageData.trace data (noContext header) (children.map noContext)
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| msg => msg
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-- strip context (including environments with registered pretty printers) to prevent infinite recursion when pretty printing pretty printer error
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private def withoutContext {m} [MonadExcept Exception m] (x : m α) : m α :=
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tryCatch x fun
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| Exception.error ref msg => throw <| Exception.error ref (noContext msg)
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| ex => throw ex
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builtin_initialize
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ppFnsRef.set {
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ppExprWithInfos := fun ctx e => ctx.runMetaM <| withoutContext <| ppExprWithInfos e,
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ppTerm := fun ctx stx => ctx.runCoreM <| withoutContext <| ppTerm stx,
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ppLevel := fun ctx l => return l.format (mvars := getPPMVars ctx.opts),
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ppGoal := fun ctx mvarId => ctx.runMetaM <| withoutContext <| Meta.ppGoal mvarId
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}
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builtin_initialize
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registerTraceClass `PrettyPrinter
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@[builtin_init]
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unsafe def registerParserCompilers : IO Unit := do
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ParserCompiler.registerParserCompiler ⟨`parenthesizer, parenthesizerAttribute, combinatorParenthesizerAttribute⟩
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ParserCompiler.registerParserCompiler ⟨`formatter, formatterAttribute, combinatorFormatterAttribute⟩
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end PrettyPrinter
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namespace MessageData
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open Lean PrettyPrinter Delaborator
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/--
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Turns a `MetaM FormatWithInfos` into a `MessageData.lazy` which will run the monadic value.
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-/
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def ofFormatWithInfosM (fmt : MetaM FormatWithInfos) : MessageData :=
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.lazy fun ctx => ctx.runMetaM <|
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.ofFormatWithInfos <$> fmt
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/--
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Turns a `MetaM MessageData` into a `MessageData.lazy` which will run the monadic value.
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The optional array of expressions is used to set the `hasSyntheticSorry` fields, and should
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comprise the expressions that are included in the message data.
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-/
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def ofLazyM (f : MetaM MessageData) (es : Array Expr := #[]) : MessageData :=
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.lazy
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(f := fun ppctxt => ppctxt.runMetaM f)
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(hasSyntheticSorry := fun mvarctxt => es.any (fun a =>
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instantiateMVarsCore mvarctxt a |>.1.hasSyntheticSorry
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))
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/--
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Pretty print a const expression using `delabConst` and generate terminfo.
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This function avoids inserting `@` if the constant is for a function whose first
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argument is implicit, which is what the default `toMessageData` for `Expr` does.
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Panics if `e` is not a constant.
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-/
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def ofConst (e : Expr) : MessageData :=
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if e.isConst then
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let delab : Delab := withOptionAtCurrPos `pp.tagAppFns true delabConst
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.ofFormatWithInfosM (PrettyPrinter.ppExprWithInfos (delab := delab) e)
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else
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panic! "not a constant"
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/--
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Pretty print a constant given its name, similar to `Lean.MessageData.ofConst`.
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Uses the constant's universe level parameters when pretty printing.
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If there is no such constant in the environment, the name is simply formatted.
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-/
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def ofConstName (constName : Name) : MessageData :=
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.ofFormatWithInfosM do
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if let some info := (← getEnv).find? constName then
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let delab : Delab := withOptionAtCurrPos `pp.tagAppFns true delabConst
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PrettyPrinter.ppExprWithInfos (delab := delab) (.const constName <| info.levelParams.map mkLevelParam)
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else
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return format constName
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/-- Generates `MessageData` for a declaration `c` as `c.{<levels>} <params> : <type>`, with terminfo. -/
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def signature (c : Name) : MessageData :=
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.ofFormatWithInfosM (PrettyPrinter.ppSignature c)
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end MessageData
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end Lean
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