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fixes #25464; infer =dup for distinct types (#25501)

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fixes #25464

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
This commit is contained in:
ringabout
2026-02-11 17:46:34 +08:00
committed by GitHub
parent f62669a5d5
commit c346a2b228
2 changed files with 33 additions and 22 deletions
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48
compiler/liftdestructors.nim
View File

@@ -558,14 +558,21 @@ proc declareTempOf(c: var TLiftCtx; body: PNode; value: PNode): PNode =
v.addVar(result, value)
body.add v
proc errorDupCustomCopy(c: var TLiftCtx; t: PType) {.inline.} =
## Emit an error when generating `=dup` code and a custom `=copy` hook
## exists
proc considerInferDupFromCopy(c: var TLiftCtx; t: PType; body, x, y: PNode): bool =
## For `=dup`, if no explicit hook exists, try to infer from `=copy` hook
## to maintain backward compatibility. Returns true if inference was applied.
if c.kind == attachedDup:
let op2 = getAttachedOp(c.g, t, attachedAsgn)
var op2 = getAttachedOp(c.g, t, attachedAsgn)
if op2 != nil and sfOverridden in op2.flags:
localError(c.g.config, c.info,
"'=dup' is not provided while a custom '=copy' is defined for type '" & typeToString(t) & "'")
#markUsed(c.g.config, c.info, op, c.g.usageSym)
onUse(c.info, op2)
body.add genBuiltin(c, mWasMoved, "wasMoved", x)
body.add newHookCall(c, op2, x, y)
result = true
else:
result = false
else:
result = false
proc addIncStmt(c: var TLiftCtx; body, i: PNode) =
let incCall = genBuiltin(c, mInc, "inc", i)
@@ -1109,23 +1116,12 @@ proc fillBody(c: var TLiftCtx; t: PType; body, x, y: PNode) =
elif tfUnion in t.flags: # bug #25236
defaultOp(c, t, body, x, y)
else:
if c.kind == attachedDup:
var op2 = getAttachedOp(c.g, t, attachedAsgn)
if op2 != nil and sfOverridden in op2.flags:
# warn if a custom '=copy' exists but no '=dup' is provided
message(c.g.config, c.info, warnDeprecated,
"'=dup' is not provided while a custom '=copy' is defined for type '" & typeToString(t) & "'; this will become a compile time error in the future")
#markUsed(c.g.config, c.info, op, c.g.usageSym)
onUse(c.info, op2)
body.add newHookCall(c, t.assignment, x, y)
else:
fillBodyObjT(c, t, body, x, y)
else:
if not considerInferDupFromCopy(c, t, body, x, y):
fillBodyObjT(c, t, body, x, y)
of tyDistinct:
if not considerUserDefinedOp(c, t, body, x, y):
errorDupCustomCopy(c, t)
fillBody(c, t.elementType, body, x, y)
if not considerInferDupFromCopy(c, t, body, x, y):
fillBody(c, t.elementType, body, x, y)
of tyTuple:
fillBodyTup(c, t, body, x, y)
of tyVarargs, tyOpenArray:
@@ -1244,7 +1240,17 @@ proc genTypeFieldCopy(c: var TLiftCtx; t: PType; body, x, y: PNode) =
proc produceSym(g: ModuleGraph; c: PContext; typ: PType; kind: TTypeAttachedOp;
info: TLineInfo; idgen: IdGenerator): PSym =
if typ.kind == tyDistinct:
return produceSymDistinctType(g, c, typ, kind, info, idgen)
# For =dup, if the distinct type has a user-defined =copy, don't delegate
# to the base type. Instead fall through to the normal produceSym logic
# so that fillBody -> considerInferDupFromCopy can synthesize =dup from =copy.
if kind == attachedDup:
let copyOp = getAttachedOp(g, typ, attachedAsgn)
if copyOp != nil and sfOverridden in copyOp.flags:
discard "fall through to normal produceSym logic"
else:
return produceSymDistinctType(g, c, typ, kind, info, idgen)
else:
return produceSymDistinctType(g, c, typ, kind, info, idgen)
result = getAttachedOp(g, typ, kind)
if result == nil:

7
tests/destructor/tdup_from_copy.nim
View File

@@ -1,5 +1,10 @@
discard """
errormsg: "'=dup' is not provided while a custom '=copy' is defined for type 'Foo'"
output: '''
copy!
copy!
3
2
'''
"""
type Foo = distinct int