Fix default arguments bug and improve `MethodRedefinitionWarning`

[wesselb]

What the title says. WIP.

[coveralls]

Pull Request Test Coverage Report for Build 9635565885

Details

• 11 of 12 (91.67%) changed or added relevant lines in 4 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 99.682%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
plum/resolver.py	6	7	85.71%
<!--	Total:	11	12

Files with Coverage Reduction	New Missed Lines	%
plum/signature.py	2	98.77%
<!--	Total:	2

Totals
Change from base Build 9552070800:	-0.2%
Covered Lines:	1253
Relevant Lines:	1257

---

💛 - Coveralls

[PhilipVinc]

@wesselb The warning is very noisy and several users are complaining. Can we revert the previous PR until we have something that works fine?

[wesselb]

@PhilipVinc I agree that it's noisy, but it's also already uncovered some issues, so it does have significant utility.

How about an opt-out mechanism, where the warning is supressed if the module of the implementation that overwrites the current method is part of a list?

You'd then do something like

from plum import opt_out_method_redefinition_warning_for_package

opt_out_method_redefinition_warning_for_package("netket")

[PhilipVinc]

What issues?

[wesselb]

E.g., this currently happens on master:

In [1]: from plum import dispatch
   ...:
   ...:
   ...: @dispatch.multi((int, float))
   ...: def f(x: int, y: float, z: float = 1):
   ...:     pass
   ...:
   ...:
   ...: print(f.methods)
List of 2 method(s):
    [0] f(x: int, y: float)
        <function f at 0x7f84606ea040> @ /<ipython-input-1-a3ba1c0fba39>:4
    [1] f(x: int)
        <function f at 0x7f84606ea040> @ /<ipython-input-1-a3ba1c0fba39>:4

This PR fixes that bug.

It's also raising some redefinition warnings in other packages of mine where I wouldn't expect them, so I'm digging into those and might find bugs there too.

[coveralls]

Pull Request Test Coverage Report for Build 9817867630

Details

• 11 of 12 (91.67%) changed or added relevant lines in 4 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 99.684%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
plum/resolver.py	6	7	85.71%
<!--	Total:	11	12

Files with Coverage Reduction	New Missed Lines	%
plum/signature.py	2	98.75%
<!--	Total:	2

Totals
Change from base Build 9817780198:	-0.2%
Covered Lines:	1261
Relevant Lines:	1265

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9817905029

Details

• 11 of 12 (91.67%) changed or added relevant lines in 4 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 99.684%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
plum/resolver.py	6	7	85.71%
<!--	Total:	11	12

Files with Coverage Reduction	New Missed Lines	%
plum/signature.py	2	98.75%
<!--	Total:	2

Totals
Change from base Build 9817780198:	-0.2%
Covered Lines:	1261
Relevant Lines:	1265

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9818904615

Details

• 23 of 23 (100.0%) changed or added relevant lines in 5 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 99.763%

---

Files with Coverage Reduction	New Missed Lines	%
plum/signature.py	2	98.75%
<!--	Total:	2

Totals
Change from base Build 9817780198:	-0.2%
Covered Lines:	1265
Relevant Lines:	1268

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9819016971

Details

• 23 of 23 (100.0%) changed or added relevant lines in 5 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 99.763%

---

Files with Coverage Reduction	New Missed Lines	%
plum/signature.py	2	98.75%
<!--	Total:	2

Totals
Change from base Build 9817780198:	-0.2%
Covered Lines:	1265
Relevant Lines:	1268

---

💛 - Coveralls