/type-check

Check Python code for type hint completeness and correctness:

Type Hint Checks:

1. Function Annotations

   • All functions should have parameter type hints
   • Return type should always be specified (use -> None explicitly)
   • Use typing module for complex types

2. Common Type Patterns

   # Basic types
   def process(name: str, count: int) -> bool: ...
   
   # Collections
   from typing import List, Dict, Set, Tuple
   def get_items() -> List[str]: ...
   def get_mapping() -> Dict[str, int]: ...
   
   # Optional values
   from typing import Optional
   def find_user(id: int) -> Optional[User]: ...
   
   # Union types
   from typing import Union
   def process(data: Union[str, bytes]) -> str: ...
   
   # Use pipe syntax (Python 3.10+)
   def process(data: str | bytes) -> str: ...
   

3. Advanced Type Patterns

   # Callable
   from typing import Callable
   def apply(func: Callable[[int, int], int]) -> int: ...
   
   # TypeVar for generic functions
   from typing import TypeVar
   T = TypeVar('T')
   def first(items: List[T]) -> T: ...
   
   # Protocol for structural subtyping
   from typing import Protocol
   class Sized(Protocol):
       def __len__(self) -> int: ...
   

4. Class Attributes

   • Use class-level annotations for attributes
   • Consider dataclasses for data-heavy classes
   • Use @property with type hints

5. Common Mistakes

   # ❌ Don't use Any when specific type is known
   def process(x: Any) -> Any: ...
   
   # ❌ Don't forget return type
   def process(x: int): ...
   
   # ❌ Don't use comments for types
   def process(x):  # type: int
       ...
   
   # ✅ Use proper type hints
   def process(x: int) -> int: ...
   

6. Type Checking Tools

   • Mention mypy for static type checking
   • Use pyright or pyre as alternatives
   • Enable strict mode for better coverage

Output Format:

🔴 MISSING: [Function/Class missing type hints]
   Location: [file:line]
   Fix: [Add proper type hints with example]

🟡 IMPRECISE: [Using Any or generic type]
   Location: [file:line]
   Why: [Specific type is better for documentation and checking]
   Fix: [More precise type hint]

💡 SUGGESTION: [Modern type pattern]
   Location: [file:line]
   Before: [Old pattern]
   After: [Modern alternative]

Check for missing type hints in all public functions and methods.