A linter is used to find errors, warnings, or stylistic problems in source code before compilation or runtime. When a linter is integrated with an IDE (such as VS Code), this is all done in real time as you type, and the results of linting are shown in a variety of ways.
The term "lint" comes from software used by Bell Labs starting in 1978 that found small defects in code, just like a dryer finds small pieces of lint in clothes (see wikipedia article).
With the proper configuration, VS Code will warn about unused or unreachable code by greying out (or dimming) Python code in the following cases:
- Unused imports
- Unused variables
- Unreachable code
- Unused functions
Mouse hover over a greyed out word to get info about the warning:
Errors in Python code are indicated with red squiggles in the following cases:
- Import not found
- Syntax error
- Incorrect argument type (when using static type hints)
- Mismatched parentheses or quotes
- etc.
Warnings are indicated with yellow squiggles.
See yellow-warning-squiggles.py
Other color squiggles can indicate other problems such as unrecommended code constructs or styles.
Open files with errors or warnings are highlighted in red or yellow in the file explorer.
Errors and warnings for open files are also listed in the PROBLEMS tab in the terminal area.
