diff --git a/src/Lean/Compiler/IR/Borrow.lean b/src/Lean/Compiler/IR/Borrow.lean
index 93979c8964..492785bd6d 100644
--- a/src/Lean/Compiler/IR/Borrow.lean
+++ b/src/Lean/Compiler/IR/Borrow.lean
@@ -70,15 +70,16 @@ def initBorrow (ps : Array Param) : Array Param :=
 def initBorrowIfNotExported (exported : Bool) (ps : Array Param) : Array Param :=
   if exported then ps else initBorrow ps
 
-partial def visitFnBody (fnid : FunId) : FnBody → StateM ParamMap Unit
-  | .jdecl j xs v b  => do
+partial def visitFnBody (fnid : FunId) (b : FnBody) : StateM ParamMap Unit := do
+  match b with
+  | .jdecl j xs v b  =>
     modify fun m => m.insert (.jp fnid j) (initBorrow xs)
     visitFnBody fnid v
     visitFnBody fnid b
   | .case _ _ _ alts => alts.forM fun alt => visitFnBody fnid alt.body
-  | e => do
-    unless e.isTerminal do
-      visitFnBody fnid e.body
+  | _ => do
+    unless b.isTerminal do
+      visitFnBody fnid b.body
 
 def visitDecls (env : Environment) (decls : Array Decl) : StateM ParamMap Unit :=
   decls.forM fun decl => match decl with
@@ -231,19 +232,33 @@ def ownArgsIfParam (xs : Array Arg) : M Unit := do
     | .var x => if ctx.paramSet.contains x.idx then ownVar x
     | .erased => pure ()
 
-def collectExpr (z : VarId) : Expr → M Unit
-  | .reset _ x      => ownVar z *> ownVar x
-  | .reuse x _ _ ys => ownVar z *> ownVar x *> ownArgsIfParam ys
-  | .ctor _ xs      => ownVar z *> ownArgsIfParam xs
-  | .proj _ x       => do
+def collectExpr (z : VarId) (e : Expr) : M Unit := do
+  match e with
+  | .reset _ x =>
+    ownVar z
+    ownVar x
+  | .reuse x _ _ ys =>
+    ownVar z
+    ownVar x
+    ownArgsIfParam ys
+  | .ctor _ xs =>
+    ownVar z
+    ownArgsIfParam xs
+  | .proj _ x =>
     if (← isOwned x) then ownVar z
     if (← isOwned z) then ownVar x
-  | .fap g xs       => do
+  | .fap g xs =>
     let ps ← getParamInfo (.decl g)
-    ownVar z *> ownArgsUsingParams xs ps
-  | .ap x ys        => ownVar z *> ownVar x *> ownArgs ys
-  | .pap _ xs       => ownVar z *> ownArgs xs
-  | _               => pure ()
+    ownVar z
+    ownArgsUsingParams xs ps
+  | .ap x ys =>
+    ownVar z
+    ownVar x
+    ownArgs ys
+  | .pap _ xs =>
+    ownVar z
+    ownArgs xs
+  | _ => pure ()
 
 def preserveTailCall (x : VarId) (v : Expr) (b : FnBody) : M Unit := do
   let ctx ← read
@@ -258,20 +273,24 @@ def preserveTailCall (x : VarId) (v : Expr) (b : FnBody) : M Unit := do
 def updateParamSet (ctx : BorrowInfCtx) (ps : Array Param) : BorrowInfCtx :=
   { ctx with paramSet := ps.foldl (fun s p => s.insert p.x.idx) ctx.paramSet }
 
-partial def collectFnBody : FnBody → M Unit
-  | .jdecl j ys v b => do
+partial def collectFnBody (b : FnBody) : M Unit := do
+  match b with
+  | .jdecl j ys v b =>
     withReader (fun ctx => updateParamSet ctx ys) (collectFnBody v)
     let ctx ← read
     updateParamMap (.jp ctx.currFn j)
     collectFnBody b
-  | .vdecl x _ v b => collectFnBody b *> collectExpr x v *> preserveTailCall x v b
-  | .jmp j ys      => do
+  | .vdecl x _ v b =>
+    collectFnBody b
+    collectExpr x v
+    preserveTailCall x v b
+  | .jmp j ys =>
     let ctx ← read
     let ps ← getParamInfo (.jp ctx.currFn j)
     ownArgsUsingParams ys ps -- for making sure the join point can reuse
     ownParamsUsingArgs ys ps  -- for making sure the tail call is preserved
   | .case _ _ _ alts => alts.forM fun alt => collectFnBody alt.body
-  | e                => do unless e.isTerminal do collectFnBody e.body
+  | _ => do unless b.isTerminal do collectFnBody b.body
 
 partial def collectDecl : Decl → M Unit
   | .fdecl (f := f) (xs := ys) (body := b) .. =>