feat: unfold ident,+

src/Init/Tactics.lean

@@ -260,10 +260,10 @@ syntax (name := dsimp) "dsimp " (config)? (discharger)? (&"only ")? ("[" (simpEr
   This is a low-level tactic, it will expose how recursive definitions have been compiled by Lean. -/
 syntax (name := delta) "delta " ident (location)? : tactic
 /--
-  `unfold id` unfolds definition `id`. For non-recursive definitions, this tactic is identical to `delta`.
+  `unfold id,+` unfolds definition `id`. For non-recursive definitions, this tactic is identical to `delta`.
   For recursive definitions, it hides the encoding tricks used by the Lean frontend to convince the
   kernel that the definition terminates. -/
-syntax (name := unfold) "unfold " ident (location)? : tactic
+syntax (name := unfold) "unfold " ident,+ (location)? : tactic
 
 -- Auxiliary macro for lifting have/suffices/let/...
 -- It makes sure the "continuation" `?_` is the main goal after refining

src/Lean/Elab/Tactic/Unfold.lean

@@ -21,11 +21,8 @@ def unfoldTarget (declName : Name) : TacticM Unit := do
 -/
 @[builtinTactic Lean.Parser.Tactic.unfold] def evalUnfold : Tactic := fun stx => do
   let loc := expandOptLocation stx[2]
-  if stx[1].isIdent then
-    go stx[1] loc
-  else
-    for declNameId in stx[1].getSepArgs do
-      go declNameId loc
+  for declNameId in stx[1].getSepArgs do
+    go declNameId loc
 where
   go (declNameId : Syntax) (loc : Location) : TacticM Unit := do
     let declName ← resolveGlobalConstNoOverload declNameId

tests/lean/run/unfoldMany.lean

@@ -0,0 +1,7 @@
+def f (x : Nat) := x + 1
+
+def g (x : Nat) := f x + f x
+
+example : g x > 0 := by
+  unfold g, f
+  simp_arith