• Are you reporting a bug, or opening a feature request?

bug

• Please insert below the code you are checking with mypy,
  or a mock-up repro if the source is private. We would appreciate
  if you try to simplify your case to a minimal repro.

def f(
    a: int,
    b: int = 1,
    c: int = 2,
    d: int = 3,
    e: int = 4):
    pass

f(b=4)

• What is the actual behavior/output?

a.py:9: error: Missing positional arguments "a", "c", "d", "e" in call to "f"

• What is the behavior/output you expect?

a.py:9: error: Missing positional argument "a" in call to "f"

It is only necessary to add a, so c, d, and e should not be mentioned in the error.

• What are the versions of mypy and Python you are using?
  Do you see the same issue after installing mypy from Git master?

Python 3.7.4
mypy 0.730+dev.61cdc95699233a9c20622949fcafcc03f7e31196

Still see the issue with latest mypy.

• What are the mypy flags you are using? (For example --strict-optional)

none