From 9182c03d4786d6bf61845aaa9e5aa1e1c0d80f47 Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Wed, 1 Apr 2026 19:15:00 +0800
Subject: [PATCH] refactor: replace elemSupportsCopyMem with supportsCopyMem
 for clarity and consistency

---
 compiler/liftdestructors.nim | 10 ++--------
 compiler/semmagic.nim        |  4 +---
 compiler/types.nim           |  5 +++++
 3 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/compiler/liftdestructors.nim b/compiler/liftdestructors.nim
index e5a3cc6337..611f6f288a 100644
--- a/compiler/liftdestructors.nim
+++ b/compiler/liftdestructors.nim
@@ -620,12 +620,6 @@ proc checkSelfAssignment(c: var TLiftCtx; t: PType; body, x, y: PNode) =
   cond.typ = getSysType(c.g, c.info, tyBool)
   body.add genIf(c, cond, newTreeI(nkReturnStmt, c.info, newNodeI(nkEmpty, c.info)))
 
-proc elemSupportsCopyMem(t: PType): bool =
-  ## Returns true if the element type of seq `t` supports bulk memory copy
-  ## (i.e., has no GC refs and no destructors).
-  let elemType = t.elementType.skipTypes({tyVar, tyLent, tyGenericInst, tyAlias, tySink, tyInferred})
-  result = not containsGarbageCollectedRef(elemType) and not hasDestructor(elemType)
-
 proc genBulkCopySeq(c: var TLiftCtx; t: PType; body, x, y: PNode) =
   ## Generates a call to nimCopySeqPayload for bulk memcpy of seq data.
   let elemType = t.elementType
@@ -650,7 +644,7 @@ proc fillSeqOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
   case c.kind
   of attachedDup:
     body.add setLenSeqCall(c, t, x, y)
-    if elemSupportsCopyMem(t):
+    if supportsCopyMem(t):
       genBulkCopySeq(c, t, body, x, y)
     else:
       forallElements(c, t, body, x, y)
@@ -665,7 +659,7 @@ proc fillSeqOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
     # For trivially copyable types, use bulk copyMem instead of element loop.
     checkSelfAssignment(c, t, body, x, y)
     body.add setLenSeqCall(c, t, x, y)
-    if elemSupportsCopyMem(t):
+    if supportsCopyMem(t):
       genBulkCopySeq(c, t, body, x, y)
     else:
       forallElements(c, t, body, x, y)
diff --git a/compiler/semmagic.nim b/compiler/semmagic.nim
index 87e085d4fd..542e5ab054 100644
--- a/compiler/semmagic.nim
+++ b/compiler/semmagic.nim
@@ -232,9 +232,7 @@ proc evalTypeTrait(c: PContext; traitCall: PNode, operand: PType, context: PSym)
   of "stripGenericParams":
     result = uninstantiate(operand).toNode(traitCall.info)
   of "supportsCopyMem":
-    let t = operand.skipTypes({tyVar, tyLent, tyGenericInst, tyAlias, tySink, tyInferred})
-    let complexObj = containsGarbageCollectedRef(t) or
-                     hasDestructor(t)
+    let complexObj = supportsCopyMem(operand)
     result = newIntNodeT(toInt128(ord(not complexObj)), traitCall, c.idgen, c.graph)
   of "canFormCycles":
     result = newIntNodeT(toInt128(ord(types.canFormAcycle(c.graph, operand))), traitCall, c.idgen, c.graph)
diff --git a/compiler/types.nim b/compiler/types.nim
index e18f97ff36..d38c2a4140 100644
--- a/compiler/types.nim
+++ b/compiler/types.nim
@@ -1779,3 +1779,8 @@ proc reduceToBase*(f: PType): PType =
     result = f.elementType
   else:
     result = f
+
+proc supportsCopyMem*(t: PType): bool =
+  let t = t.skipTypes({tyVar, tyLent, tyGenericInst, tyAlias, tySink, tyInferred})
+  result = containsGarbageCollectedRef(t) or
+                     hasDestructor(t)