Why is this an issue?

The constructor of a class does not call the constructors of any of its ancestor classes by default. This means that the fields of any ancestor classes will not be initialized, potentially causing unexpected program errors. The constructor of the ancestor class can be called using the inherited keyword.

Note that while TObject does not contain any code in its constructor or destructor, the inherited keyword should still be used for immediate descendants. This is for consistency and to guard against bugs that may emerge if the class's parent is changed from TObject in future.

How to fix it

If there is a parent constructor with the same parameters, adding an inherited to the beginning of the method will call it: 

constructor TParent.Create;
  // ...
end;

constructor TChild.Create;
begin
  FMyStr := 'hello!';
end;

constructor TParent.Create;
  // ...
end;

constructor TChild.Create;
begin
  inherited;
  FMyStr := 'hello!';
end;

Otherwise, the desired parent constructor can be called using an inherited keyword followed by its name and arguments: 

constructor TParent.Create(MyInt: Integer);
  // ...
end;

constructor TChild.Create(MyStr: string; MyInt: Integer);
begin
  FMyStr := MyStr;
end;

constructor TParent.Create(MyInt: Integer);
  // ...
end;

constructor TChild.Create(MyStr: string; MyInt: Integer);
begin
  inherited Create(MyInt);
  FMyStr := MyStr;
end;

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