• I am on the latest Poetry version.
• I have searched the issues of this repo and believe that this is not a duplicate.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: elementary OS 5.0 Juno
• Poetry version:1.0.3
• Link of a Gist with the contents of your pyproject.toml file:

[tool.poetry]
name = "tmpoetry"
version = "0.1.0"
description = "sdfg"
authors = ["Author <author@mail.com>"]

[tool.poetry.dependencies]
python = "^3.6"
mypy = "^0.701"
pylint = "^2.3"

Issue

• When a (sub)dependency has different requirements for different python versions, it appears twice in poetry.lock. In itself this is no problem, but poetry export generates duplicate entries.

• In this use case, the command poetry add fails because said library has "conflifting" versions.
  (try poetry add astroid)