fixes #13112 (#13127)

* improve line error information

* fixes #13112

compiler/semmagic.nim

@@ -383,7 +383,7 @@ proc semUnown(c: PContext; n: PNode): PNode =
   # little hack for injectdestructors.nim (see bug #11350):
   #result[0].typ = nil
 
-proc turnFinalizerIntoDestructor(c: PContext; orig: PSym): PSym =
+proc turnFinalizerIntoDestructor(c: PContext; orig: PSym; info: TLineInfo): PSym =
   # We need to do 2 things: Replace n.typ which is a 'ref T' by a 'var T' type.
   # Replace nkDerefExpr by nkHiddenDeref
   # nkDeref is for 'ref T':  x[].field
@@ -400,7 +400,9 @@ proc turnFinalizerIntoDestructor(c: PContext; orig: PSym): PSym =
     #  result =
 
   result = copySym(orig)
+  result.info = info
   result.flags.incl sfFromGeneric
+  result.owner = orig
   let origParamType = orig.typ[1]
   let newParamType = makeVarType(result, origParamType.skipTypes(abstractPtrs))
   let oldParam = orig.typ.n[1].sym
@@ -477,7 +479,12 @@ proc magicsAfterOverloadResolution(c: PContext, n: PNode,
     if n[^1].kind == nkSym and n[^1].sym.kind notin {skProc, skFunc}:
       localError(c.config, n.info, "finalizer must be a direct reference to a proc")
     elif optTinyRtti in c.config.globalOptions:
-      bindTypeHook(c, turnFinalizerIntoDestructor(c, n[^1].sym), n, attachedDestructor)
+      # check if we converted this finalizer into a destructor already:
+      let t = whereToBindTypeHook(c, n[^1].sym.typ[1].skipTypes(abstractInst+{tyRef}))
+      if t != nil and t.attachedOps[attachedDestructor] != nil and t.attachedOps[attachedDestructor].owner == n[^1].sym:
+        discard "already turned this one into a finalizer"
+      else:
+        bindTypeHook(c, turnFinalizerIntoDestructor(c, n[^1].sym, n.info), n, attachedDestructor)
     result = n
   of mDestroy:
     result = n

compiler/semstmts.nim

@@ -1603,6 +1603,15 @@ proc prevDestructor(c: PContext; prevOp: PSym; obj: PType; info: TLineInfo) =
     msg.add "; previous declaration was here: " & (c.config $ prevOp.info)
   localError(c.config, info, errGenerated, msg)
 
+proc whereToBindTypeHook(c: PContext; t: PType): PType =
+  result = t
+  while true:
+    if result.kind in {tyGenericBody, tyGenericInst}: result = result.lastSon
+    elif result.kind == tyGenericInvocation: result = result[0]
+    else: break
+  if result.kind in {tyObject, tyDistinct, tySequence, tyString}:
+    result = canonType(c, result)
+
 proc bindTypeHook(c: PContext; s: PSym; n: PNode; op: TTypeAttachedOp) =
   let t = s.typ
   var noError = false

tests/destructor/tfinalizer.nim

@@ -1,6 +1,7 @@
 discard """
   cmd: "nim c --gc:arc $file"
   output: '''Foo(field: "Dick Laurent", k: ka, x: 0.0)
+Nobody is dead
 Dick Laurent is dead'''
 """
 
@@ -23,3 +24,8 @@ x.field = "Dick Laurent"
 # reference to a great movie. If you haven't seen it, highly recommended.
 
 echo repr x
+
+# bug #13112: bind the same finalizer multiple times:
+var xx: Foo
+new(xx, finalizer)
+xx.field = "Nobody"