Can't understand why pyright does not report this very simple error

[belugame]

version: 1.1.381

I am very new to using pyright and just wanted to try it out.
My sample code is:

def foo(a: int):
    return a


foo("a")

I expect pyright to complain about that the method receives a string argument and not an integer argument. So I call it on the CLI:

pyright foo.py
0 errors, 0 warnings, 0 informations 

But it reports nothing. While mypy says:
foo.py:5: error: Argument 1 to "foo" has incompatible type "str"; expected "int" [arg-type]

Here is the verbose output of pyright:

Auto-excluding **/node_modules
Auto-excluding **/__pycache__
Auto-excluding **/.*
Search paths for file:///home/myuser/foo
  /home/myuser/.cache/pyright-python/1.1.381/node_modules/pyright/dist/typeshed-fallback/stdlib
  /home/myuser/foo
  /home/myuser/foo/typings
  /home/myuser/.cache/pyright-python/1.1.381/node_modules/pyright/dist/typeshed-fallback/stubs/...
  /usr/lib/python3.12
  /usr/lib/python3.12/lib-dynload
  /home/myuser/.local/share/virtualenvs/myproject-cpciIMar/lib/python3.12/site-packages
Found 1 source file
Could not import '_typing' in file '/usr/lib/python3.12/typing.py'
  Looking in stubPath 'file:///home/myuser/foo/typings'
  Attempting to resolve stub package using root path 'file:///home/myuser/foo/typings'
  Attempting to resolve using root path 'file:///home/myuser/foo/typings'
  Looking in root directory of execution environment 'file:///home/myuser/foo'
  Attempting to resolve stub package using root path 'file:///home/myuser/foo'
  Attempting to resolve using root path 'file:///home/myuser/foo'
  Looking for typeshed stdlib path
  Looking for typeshed stdlib path
  Attempting to resolve using root path 'file:///home/myuser/.cache/pyright-python/1.1.381/node_modules/pyright/dist/typeshed-fallback/stdlib'
  Typeshed path not found
  Finding python search paths
  Executing interpreter: 'python3'
  Skipping '/usr/lib/python312.zip' because it is not a valid directory
  Received 3 paths from interpreter
    file:///usr/lib/python3.12
    file:///usr/lib/python3.12/lib-dynload
    file:///home/myuser/.local/share/virtualenvs/myproject-cpciIMar/lib/python3.12/site-packages
  Looking in python search path 'file:///usr/lib/python3.12'
  Attempting to resolve stub package using root path 'file:///usr/lib/python3.12'
  Attempting to resolve using root path 'file:///usr/lib/python3.12'
  Looking in python search path 'file:///usr/lib/python3.12/lib-dynload'
  Attempting to resolve stub package using root path 'file:///usr/lib/python3.12/lib-dynload'
  Attempting to resolve using root path 'file:///usr/lib/python3.12/lib-dynload'
  Looking in python search path 'file:///home/myuser/.local/share/virtualenvs/myproject-cpciIMar/lib/python3.12/site-packages'
  Attempting to resolve stub package using root path 'file:///home/myuser/.local/share/virtualenvs/myproject-cpciIMar/lib/python3.12/site-packages'
  Attempting to resolve using root path 'file:///home/myuser/.local/share/virtualenvs/myproject-cpciIMar/lib/python3.12/site-packages'
  Looking for typeshed third-party path
  Looking for typeshed stubs path
  Typeshed path not found
Heap stats: total_memory_size=19891MB, total_free_size=14020MB, total_heap_size=80MB, used_heap_size=58MB, cross_worker_used_heap_size=58MB, total_physical_size=79MB, total_available_size=4085MB, heap_size_limit=4144MB
pyright 1.1.381
0 errors, 0 warnings, 0 informations 
Completed in 1.263sec

Is something wrong in my setup?

[erictraut]

There must be something wrong with your setup.

Here's a link to the pyright playground that shows what you should see.

When I follow the steps above, I see the following output:

/path/foo.py
/path/foo.py:5:5 - error: Argument of type "Literal['a']" cannot be assigned to parameter "a" of type "int" in function "foo"
    "Literal['a']" is not assignable to "int" (reportArgumentType)
1 error, 0 warnings, 0 informations 

The verbose output includes Typeshed path not found, which I can't explain. Pyright bundles the typeshed stubs. They should be located at file:///home/myuser/.cache/pyright-python/1.1.381/node_modules/pyright/dist/typeshed-fallback/stdlib on your system.

I wonder if your pyright install was corrupted. Perhaps try uninstalling it and reinstalling.

One other idea... Which version of node do you have installed on your system? (Type node --version.) If it's really old, you might try updating it.

[belugame]

Hey Eric,
Thank you for your reply and sorry I did not get back to you sooner.

In the mentioned folder /home/myuser/.cache/pyright-python/1.1.381/node_modules/pyright/dist/typeshed-fallback/stdlib I find many files:

abc.pyi		bisect.pyi	      _compat_pickle.pyi  dataclasses.pyi	faulthandler.pyi  grp.pyi		io.pyi		marshal.pyi	  _operator.pyi     posix.pyi		  random.pyi	     smtpd.pyi		struct.pyi	      urllib
aifc.pyi	... and so on

My node version seems up to date with the stable release:

node --version
v20.17.0

I tried re-installing pyright with pip too, but the result is the same.