Translated from French post by Paul TOTH https://plus.google.com/+PaulTOTH/posts/eRCT9VZFwx7

whenConstsDontCompile.pas

type
  TElement = record
    Idx    : Integer;
    Valeurs: TArray<Integer>;
  end;

  TElements = TArray<TElement>;

const
  El1 : TElement = (Idx: 1; Valeurs: [1]); // ok

  Elements1 : array[0..0] of TElement = ((Idx: 1; Valeurs: [1])); // ok

  Elements2 : TElements = []; // ok

  Elements3 : TElements = [El1];  // E2026 Constant expression expected
  Elements4 : TElements = [(Idx: 1; Valeurs: [1])]; // E2003: Undeclared identifier: 'Idx'