Diesel complains that it can't find Cargo.toml despite successfully running migrations

[SamWhited]

Setup

Versions

• Rust: 1.28.0 nightly
• Diesel: 1.3.1
• Database: postgres
• Operating System arch

Feature Flags

• diesel: postgres

Problem Description

When running any migration command (eg. diesel migration redo) migrations complete successfully, but diesel complains:

Unable to find Cargo.toml in this directory or any parent directories.

I don't have a Cargo.toml because I am not using Cargo.

What is the expected output?

No unnecessary warnings about a build system that I am not using.

What is the actual output?

Unable to find Cargo.toml in this directory or any parent directories.

Checklist

• I have already looked over the issue tracker for similar issues.
• This issue can be reproduced on Rust's stable channel. (Your issue will be
  closed if this is not the case)

eg.

$ diesel migration redo
Rolling back migration 2018-06-13-215447_init
Running migration 2018-06-13-215447_init
Unable to find Cargo.toml in this directory or any parent directories.

[sgrif]

Looks like this error occurs when Diesel CLI looks for a config file (the default location is in the same place as Cargo.toml)