Added documentation about higher-order functions.

docs/mypy-comparison.md

@@ -346,6 +346,29 @@ def func2(x: list[int], y: list[str] | int):
     reveal_type(v2) # pyright: "list[int | str]" ("list[list[str] | int]" is also a valid answer)
 ```
 
+#### Constraint Solver: Higher-order Functions
+
+If a generic higher-order function is passed another generic callable as an argument, pyright is able to solve the type variables for both the target function and the argument. Mypy isn’t able to handle higher-order functions.
+
+```python
+def identity(val: T) -> T:
+    return val
+
+
+def higher_order1(cb: Callable[[S], T], arg: S) -> T:
+    return cb(arg)
+
+v1 = higher_order1(identity, 1.0)  # mypy generates an error
+reveal_type(v1)  # mypy: T, pyright: float
+
+
+def higher_order2(cb: Callable[P, R], *args: P.args, **kwargs: P.kwargs) -> R:
+    return cb(*args, **kwargs)
+
+v2 = higher_order2(identity, "")  # mypy generates an error
+reveal_type(v2)  # mypy: T, pyright: str
+```
+
 
 ### Constrained Type Variables