feat: create private aux decls in private contexts

src/Lean/CoreM.lean

@@ -102,14 +102,23 @@ partial def mkUniqueName (env : Environment) (g : DeclNameGenerator) («infix»
   let «infix» := if g.namePrefix.hasMacroScopes && infix.hasMacroScopes then infix.eraseMacroScopes else «infix»
   let base := g.namePrefix ++ «infix»
   let mut g := g
+  while isConflict (curr g base) do
+    g := g.next
+  return (curr g base, g)
+where
+  -- Check whether the name conflicts with an existing one. Conflicts ignore privacy.
   -- NOTE: We only check the current branch and rely on the documented invariant instead because we
   -- do not want to block here and because it would not solve the issue for completely separated
   -- threads of elaboration such as in Aesop's backtracking search.
-  while env.containsOnBranch (curr g base) do
-    g := g.next
-  return (curr g base, g)
-where curr (g : DeclNameGenerator) (base : Name) : Name :=
-  g.idxs.foldr (fun i n => n.appendIndexAfter i) base
+  isConflict (n : Name) : Bool :=
+    (env.setExporting false).containsOnBranch n ||
+    isPrivateName n && (env.setExporting false).containsOnBranch (privateToUserName n) ||
+    !isPrivateName n && (env.setExporting false).containsOnBranch (mkPrivateName env n)
+  curr (g : DeclNameGenerator) (base : Name) : Name := Id.run do
+    let mut n := g.idxs.foldr (fun i n => n.appendIndexAfter i) base
+    if env.header.isModule && !env.isExporting && !isPrivateName n then
+      n := mkPrivateName env n
+    return n
 
 def mkChild (g : DeclNameGenerator) : DeclNameGenerator × DeclNameGenerator :=
   ({ g with parentIdxs := g.idx :: g.parentIdxs, idx := 1 },

src/Lean/Elab/AuxDef.lean

@@ -27,7 +27,8 @@ def elabAuxDef : CommandElab
     -- We use a new generator here because we want more control over the name; the default would
     -- create a private name that then breaks the macro below. We assume that `aux_def` is not used
     -- with the same arguments in parallel contexts.
-    let (id, _) := { namePrefix := ns : DeclNameGenerator }.mkUniqueName (← getEnv) («infix» := Name.mkSimple id)
+    let env := (← getEnv).setExporting true
+    let (id, _) := { namePrefix := ns : DeclNameGenerator }.mkUniqueName env («infix» := Name.mkSimple id)
     let id := id.replacePrefix ns Name.anonymous -- TODO: replace with def _root_.id
     elabCommand <|
       ← `($[$doc?:docComment]? $[$attrs?:attributes]?

src/Lean/Elab/SyntheticMVars.lean

@@ -347,8 +347,9 @@ mutual
   If `report := false`, then `runTactic` will not capture exceptions nor will report unsolved goals. Unsolved goals become exceptions.
   -/
   partial def runTactic (mvarId : MVarId) (tacticCode : Syntax) (kind : TacticMVarKind) (report := true) : TermElabM Unit := withoutAutoBoundImplicit do
+    let wasExporting := (← getEnv).isExporting
     -- exit exporting context if entering proof
-    let isNoLongerExporting ← pure (← getEnv).isExporting <&&> do
+    let isNoLongerExporting ← pure wasExporting <&&> do
       mvarId.withContext do
         isProp (← mvarId.getType)
     instantiateMVarDeclMVars mvarId
@@ -359,7 +360,7 @@ mutual
     if isNoLongerExporting then
       let mvarDecl ← getMVarDecl mvarId
       mvarId' := (← mkFreshExprMVarAt mvarDecl.lctx mvarDecl.localInstances mvarDecl.type mvarDecl.kind).mvarId!
-    withExporting (isExporting := (← getEnv).isExporting && !isNoLongerExporting) do
+    withExporting (isExporting := wasExporting && !isNoLongerExporting) do
     /-
     TODO: consider using `runPendingTacticsAt` at `mvarId` local context and target type.
     Issue #1380 demonstrates that the goal may still contain pending metavariables.
@@ -395,7 +396,8 @@ mutual
             let mut e ← instantiateExprMVars (.mvar mvarId')
             if !e.isFVar then
               e ← mvarId'.withContext do
-                abstractProof e
+                withExporting (isExporting := wasExporting) do
+                  abstractProof e
             mvarId.assign e)
       fun ex => do
         if report then

src/Lean/Meta/AbstractNestedProofs.lean

@@ -11,9 +11,9 @@ import Lean.Meta.Transform
 namespace Lean.Meta
 
 /-- Abstracts the given proof into an auxiliary theorem, suitably pre-processing its type. -/
-def abstractProof [Monad m] [MonadLiftT MetaM m] (proof : Expr) (cache := true)
-    (postprocessType : Expr → m Expr := pure) : m Expr := do
-  let type ← inferType proof
+def abstractProof [Monad m] [MonadLiftT MetaM m] [MonadEnv m] [MonadOptions m] [MonadFinally m]
+    (proof : Expr) (cache := true) (postprocessType : Expr → m Expr := pure) : m Expr := do
+  let type ← withoutExporting do inferType proof
   let type ← (Core.betaReduce type : MetaM _)
   let type ← zetaReduce type
   let type ← postprocessType type
@@ -66,7 +66,7 @@ partial def visit (e : Expr) : M Expr := do
         lctx := lctx.modifyLocalDecl xFVarId fun _ => localDecl
       withLCtx lctx localInstances k
     checkCache { val := e : ExprStructEq } fun _ => do
-      if (← isNonTrivialProof e) then
+      if (← withoutExporting do isNonTrivialProof e) then
         /- Ensure proofs nested in type are also abstracted -/
         abstractProof e (← read).cache visit
       else match e with

src/Lean/Meta/Tactic/Simp/SimpTheorems.lean

@@ -439,11 +439,11 @@ private def mkSimpTheoremsFromConst (declName : Name) (post : Bool) (inv : Bool)
     if inv || (← shouldPreprocess type) then
       let mut r := #[]
       for (val, type) in (← preprocess val type inv (isGlobal := true)) do
-        let auxName ← mkAuxLemma cinfo.levelParams type val
-        r := r.push <| (← mkSimpTheoremCore origin (mkConst auxName us) #[] (mkConst auxName) post prio (noIndexAtArgs := false))
+        let auxName ← mkAuxLemma (kind? := `_simp) cinfo.levelParams type val
+        r := r.push <| (← withoutExporting do mkSimpTheoremCore origin (mkConst auxName us) #[] (mkConst auxName) post prio (noIndexAtArgs := false))
       return r
     else
-      return #[← mkSimpTheoremCore origin (mkConst declName us) #[] (mkConst declName) post prio (noIndexAtArgs := false)]
+      return #[← withoutExporting do mkSimpTheoremCore origin (mkConst declName us) #[] (mkConst declName) post prio (noIndexAtArgs := false)]
 
 inductive SimpEntry where
   | thm      : SimpTheorem → SimpEntry
@@ -463,7 +463,7 @@ def SimpExtension.getTheorems (ext : SimpExtension) : CoreM SimpTheorems :=
   return ext.getState (← getEnv)
 
 def addSimpTheorem (ext : SimpExtension) (declName : Name) (post : Bool) (inv : Bool) (attrKind : AttributeKind) (prio : Nat) : MetaM Unit := do
-  let simpThms ← mkSimpTheoremsFromConst declName post inv prio
+  let simpThms ← withExporting (isExporting := !isPrivateName declName) do mkSimpTheoremsFromConst declName post inv prio
   for simpThm in simpThms do
     ext.add (SimpEntry.thm simpThm) attrKind