Clarify error message for TypeVar function

mypy/message_registry.py

@@ -196,7 +196,7 @@ def with_additional_msg(self, info: str) -> ErrorMessage:
 TYPEVAR_ARG_MUST_BE_TYPE: Final = '{} "{}" must be a type'
 TYPEVAR_UNEXPECTED_ARGUMENT: Final = 'Unexpected argument to "TypeVar()"'
 UNBOUND_TYPEVAR: Final = (
-    "A function returning TypeVar should receive at least one argument containing the same TypeVar"
+    "A function returning TypeVar should have at least one same TypeVar parameter"
 )
 TYPE_PARAMETERS_SHOULD_BE_DECLARED: Final = (
     "All type parameters should be declared ({} not declared)"

test-data/unit/check-classes.test

@@ -3716,7 +3716,7 @@ def error(u_c: Type[U]) -> P: # Error here, see below
     return new_pro(u_c)  # Error here, see below
 [out]
 main:11: note: Revealed type is "__main__.WizUser"
-main:12: error: A function returning TypeVar should receive at least one argument containing the same TypeVar
+main:12: error: A function returning TypeVar should have at least one same TypeVar parameter
 main:12: note: Consider using the upper bound "ProUser" instead
 main:13: error: Value of type variable "P" of "new_pro" cannot be "U"
 main:13: error: Incompatible return value type (got "U", expected "P")

test-data/unit/check-errorcodes.test

@@ -284,7 +284,7 @@ z: y  # E: Variable "__main__.y" is not valid as a type  [valid-type] \
 from typing import TypeVar
 
 T = TypeVar('T')
-def f() -> T: pass # E: A function returning TypeVar should receive at least one argument containing the same TypeVar  [type-var]
+def f() -> T: pass # E: A function returning TypeVar should have at least one same TypeVar parameter  [type-var]
 x = f()  # E: Need type annotation for "x"  [var-annotated]
 y = []  # E: Need type annotation for "y" (hint: "y: list[<type>] = ...")  [var-annotated]
 [builtins fixtures/list.pyi]

test-data/unit/check-generics.test

@@ -1599,9 +1599,9 @@ A = TypeVar('A')
 B = TypeVar('B')
 
 def f1(x: A) -> A: ...
-def f2(x: A) -> B: ... # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
+def f2(x: A) -> B: ... # E: A function returning TypeVar should have at least one same TypeVar parameter
 def f3(x: B) -> B: ...
-def f4(x: int) -> A: ... # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
+def f4(x: int) -> A: ... # E: A function returning TypeVar should have at least one same TypeVar parameter
 
 y1 = f1
 if int():
@@ -1650,8 +1650,8 @@ B = TypeVar('B')
 T = TypeVar('T')
 def outer(t: T) -> None:
     def f1(x: A) -> A: ...
-    def f2(x: A) -> B: ... # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
-    def f3(x: T) -> A: ... # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
+    def f2(x: A) -> B: ... # E: A function returning TypeVar should have at least one same TypeVar parameter
+    def f3(x: T) -> A: ... # E: A function returning TypeVar should have at least one same TypeVar parameter
     def f4(x: A) -> T: ...
     def f5(x: T) -> T: ...
 
@@ -1818,7 +1818,7 @@ from typing import TypeVar
 A = TypeVar('A')
 B = TypeVar('B')
 def f1(x: int, y: A) -> A: ...
-def f2(x: int, y: A) -> B: ... # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
+def f2(x: int, y: A) -> B: ... # E: A function returning TypeVar should have at least one same TypeVar parameter
 def f3(x: A, y: B) -> B: ...
 g = f1
 g = f2

test-data/unit/check-inference.test

@@ -590,7 +590,7 @@ def ff() -> None:
     x = f() # E: Need type annotation for "x"
     reveal_type(x) # N: Revealed type is "Any"
 
-def f() -> T: pass # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
+def f() -> T: pass # E: A function returning TypeVar should have at least one same TypeVar parameter
 def g(a: T) -> None: pass
 
 g(None) # Ok
@@ -2693,7 +2693,7 @@ def main() -> None:
 [case testDontMarkUnreachableAfterInferenceUninhabited]
 from typing import TypeVar
 T = TypeVar('T')
-def f() -> T: pass # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
+def f() -> T: pass # E: A function returning TypeVar should have at least one same TypeVar parameter
 
 class C:
     x = f() # E: Need type annotation for "x"

test-data/unit/check-parameter-specification.test

@@ -1161,7 +1161,7 @@ def callback(func: Callable[[Any], Any]) -> None: ...
 class Job(Generic[P]): ...
 
 @callback
-def run_job(job: Job[...]) -> T: ... # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
+def run_job(job: Job[...]) -> T: ... # E: A function returning TypeVar should have at least one same TypeVar parameter
 [builtins fixtures/tuple.pyi]
 
 [case testTupleAndDictOperationsOnParamSpecArgsAndKwargs]

test-data/unit/check-selftype.test

@@ -1541,7 +1541,7 @@ class C:
     def meth(cls) -> Self: ...
     @staticmethod
     def bad() -> Self: ...  # E: Static methods cannot use Self type \
-        # E: A function returning TypeVar should receive at least one argument containing the same TypeVar \
+        # E: A function returning TypeVar should have at least one same TypeVar parameter \
         # N: Consider using the upper bound "C" instead
 
 class D(C): ...

test-data/unit/check-typevar-unbound.test

@@ -3,19 +3,19 @@ from typing import TypeVar
 
 T = TypeVar('T')
 
-def f() -> T: # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
+def f() -> T: # E: A function returning TypeVar should have at least one same TypeVar parameter
     ...
 f()
 
 U = TypeVar('U', bound=int)
 
-def g() -> U: # E: A function returning TypeVar should receive at least one argument containing the same TypeVar \
+def g() -> U: # E: A function returning TypeVar should have at least one same TypeVar parameter \
               # N: Consider using the upper bound "int" instead
     ...
 
 V = TypeVar('V', int, str)
 
-def h() -> V:  # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
+def h() -> V:  # E: A function returning TypeVar should have at least one same TypeVar parameter
     ...
 
 [case testInnerFunctionTypeVar]

test-data/unit/check-unreachable-code.test

@@ -1567,7 +1567,7 @@ from typing import TypeVar
 
 T = TypeVar("T")
 class Foo:
-    def __setitem__(self, key: str, value: str) -> T:  # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
+    def __setitem__(self, key: str, value: str) -> T:  # E: A function returning TypeVar should have at least one same TypeVar parameter
         raise Exception
 
 def f() -> None: