fixes #22662 Procs with constructor pragma doesn't initialize object's fields (#22665)

fixes #22662 Procs with constructor pragma doesn't initialize object's
fields

---------

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
(cherry picked from commit d45270bdf7)

compiler/ccgtypes.nim

@@ -660,6 +660,13 @@ proc mangleRecFieldName(m: BModule; field: PSym): Rope =
     result = rope(mangleField(m, field.name))
   if result == "": internalError(m.config, field.info, "mangleRecFieldName")
 
+proc hasCppCtor(m: BModule; typ: PType): bool = 
+  result = false
+  if m.compileToCpp and typ != nil and typ.itemId in m.g.graph.memberProcsPerType:
+    for prc in m.g.graph.memberProcsPerType[typ.itemId]:
+      if sfConstructor in prc.flags:
+        return true
+
 proc genRecordFieldsAux(m: BModule; n: PNode,
                         rectype: PType,
                         check: var IntSet; result: var Rope; unionPrefix = "") =
@@ -724,7 +731,7 @@ proc genRecordFieldsAux(m: BModule; n: PNode,
       else:
         # don't use fieldType here because we need the
         # tyGenericInst for C++ template support
-        if fieldType.isOrHasImportedCppType():
+        if fieldType.isOrHasImportedCppType() or hasCppCtor(m, field.owner.typ):
           result.addf("\t$1$3 $2{};$n", [getTypeDescAux(m, field.loc.t, check, dkField), sname, noAlias])
         else:
           result.addf("\t$1$3 $2;$n", [getTypeDescAux(m, field.loc.t, check, dkField), sname, noAlias])

tests/cpp/tconstructor.nim

@@ -3,6 +3,10 @@ discard """
   cmd: "nim cpp $file"
   output: '''
 1
+0
+123
+0
+123
 '''
 """
 
@@ -52,4 +56,21 @@ proc makeCppClass(): NimClass {. constructor: "NimClass() : CppClass(0, 0) ".} =
   this.x = 1
 
 let nimClass = makeNimClass(1)
-var nimClassDef {.used.}: NimClass  #since we explictly defined the default constructor we can declare the obj
+var nimClassDef {.used.}: NimClass  #since we explictly defined the default constructor we can declare the obj
+
+#bug: 22662
+type
+  BugClass* = object
+    x: int          # Not initialized
+
+proc makeBugClass(): BugClass {.constructor.} =
+  discard
+
+proc main =
+  for i in 0 .. 1:
+    var n = makeBugClass()
+    echo n.x
+    n.x = 123
+    echo n.x
+
+main()