kept more consistent error messaging

Author: KevinRK29

mypy/checkexpr.py

@@ -33,7 +33,7 @@
 from mypy.maptype import map_instance_to_supertype
 from mypy.meet import is_overlapping_types, narrow_declared_type
 from mypy.message_registry import ErrorMessage
-from mypy.messages import MessageBuilder, format_type
+from mypy.messages import MessageBuilder, format_type, format_type_distinctly
 from mypy.nodes import (
     ARG_NAMED,
     ARG_POS,
@@ -2387,12 +2387,19 @@ def check_call_arguments(
             has_type_errors = type_error_watcher.has_new_errors()
 
             if shift_info is not None:
-                _, param_name, expected_type, high_confidence = shift_info
+                shift_position, param_name, expected_type, high_confidence = shift_info
                 if high_confidence and param_name:
-                    type_str = format_type(expected_type, self.chk.options)
+                    positional_arg_types = [
+                        arg_types[i] for i, k in enumerate(arg_kinds) if k == nodes.ARG_POS
+                    ]
+                    actual_type = positional_arg_types[shift_position - 1]
+                    actual_str, expected_str = format_type_distinctly(
+                        actual_type, expected_type, options=self.chk.options
+                    )
                     self.msg.fail(
-                        f'Expected {type_str} for parameter "{param_name}"; '
-                        f'did you forget argument "{param_name}"?',
+                        f'Argument {shift_position} to "{func_name}" has incompatible type '
+                        f'{actual_str}; expected {expected_str} '
+                        f'(did you forget argument "{param_name}"?)',
                         context,
                         code=codes.CALL_ARG,
                     )

test-data/unit/check-functions.test

@@ -3710,15 +3710,15 @@ def f(x: int, y: str, z: bytes, aa: int) -> None: ...
 f(1, b'x', 1)
 [builtins fixtures/primitives.pyi]
 [out]
-main:3: error: Expected "str" for parameter "y"; did you forget argument "y"?
+main:3: error: Argument 2 to "f" has incompatible type "bytes"; expected "str" (did you forget argument "y"?)
 
 [case testMissingPositionalArgumentShiftedTypesFirstArg]
 def f(x: int, y: str, z: bytes) -> None: ...
 
 f("hello", b'x')
 [builtins fixtures/primitives.pyi]
 [out]
-main:3: error: Expected "int" for parameter "x"; did you forget argument "x"?
+main:3: error: Argument 1 to "f" has incompatible type "str"; expected "int" (did you forget argument "x"?)
 
 [case testMissingPositionalArgumentNoShift]
 def f(x: int, y: str, z: bytes) -> None: ...
@@ -3736,7 +3736,7 @@ def f(a: int, b: str, c: float, d: list[int], e: tuple[str, ...]) -> None: ...
 f(1, 1.5, [1, 2, 3], ("a", "b"))
 [builtins fixtures/list.pyi]
 [out]
-main:3: error: Expected "str" for parameter "b"; did you forget argument "b"?
+main:3: error: Argument 2 to "f" has incompatible type "float"; expected "str" (did you forget argument "b"?)
 
 [case testMissingPositionalArgumentShiftedWithDefaults]
 def f(x: int, y: str, z: bytes = b'default') -> None: ...