Surprising results from the HTML report

I was able to replicate your problems on mypy master (mypy 2.0.0+dev.3cda6ec255a530e7da8bec44d197399aec73e96d (compiled: no)), such as the @overload thing. I think this is a bug, especially considering that the typeshed definition of overload does not contain Any, but it is hard for me to say definitively (due to the lack of documentation).

With the following code:

from typing import overload

def foo(x):
    return x

def foo1(x: int) -> int:
    return x

def foo2(x) -> int:
    return x

def foo3(x: int):
    return x

def foo4(x: int):
    return x

@overload
def foo5(x: int) -> int: ...
@overload
def foo5(x: str) -> str: ...
def foo5(x):
    return x

@overload
def foo6(x: int) -> int: ...
@overload
def foo6(x: str) -> str: ...
def foo6(x: int|str) -> int|str:
    return x

And the following command:

uv run mypy --html-report tmp_dir tmp.py

I get the following result:

The @overload lines are red but on hover say "No Anys on this line!". Surprisingly, this is also true of def foo(x): and def foo5(x):

My isinstance lines are always colored green, not yellow. In fact, the line isinstance(1,list) is green, but on hover it says Any Types on this line: Omitted Generics (x3). I think this kind of makes sense as behavior given the rules about isinstance but I think in that case the hovertext should maybe be different.

In the following code, the print("OK") line is colored red despite on hover saying No Anys on this line!. The if isinstance(v,list): line is green despite saying Any Types on this line: Omitted Generics (x3)

v = 1
if isinstance(v,list):
    print("OK")

Possibly related: https://github.com/python/mypy/issues/14297

Originally posted by @wyattscarpenter in #13495

Reproduce the report with the supplied tmp.py example and uv run mypy --html-report tmp_dir tmp.py. Compare the HTML colors and hover text for the @overload, isinstance, and unreachable-code lines. Done means the report's visual indicators and hover descriptions consistently represent the detected Any usage and unreachable code.