Package angular has no versions that match >=5.0.0 <6.0.0 derived from:

[hpoit]

How do I solve this?

Related to #912

[johnpryan]

This is an issue with the version of angular_router you are trying to use. If you are using Dart 2 (which includes PubGrub) you can track down the issue without too many hiccups.

For example, with the Dart 2.4.0 SDK, running pub get on this file produces the following message:

Because foo depends on angular_router >=1.0.1 <2.0.0-alpha+16 which requires SDK version
  >=1.24.0 <2.0.0 or >=2.0.0-dev.3.0 <2.0.0, version solving failed.

OK, so there's an issue with angular_router. Let's see if we can relax that version:

name: foo
dependencies:
  angular: ^5.0.0
  angular_forms: ^2.0.0
  angular_router: any
dev_dependencies:
  build_runner: ">=1.6.2 <2.0.0"
  build_test: ^0.10.2
  build_web_compilers: ">=1.2.0 <3.0.0"

Now, running pub get fetches angular_router 2.0.0-alpha+22 without any issues.

[natebosch]

Looks like you're on a pre-release Dart 2 SDK. I'd recommend upgrading to a more recent one. As @johnpryan points out the newer versions of Pub have an improved version solver which gives better constraint messages.