Different expected errors while testing using Rust's nightly compiler

[clin1234]

Just as a curiosity:

diff --git a/tests/ui/invalid_argument_attributes.stderr b/tests/ui/invalid_argument_attributes.stderr
index e6c42f8..67d974b 100644
--- a/tests/ui/invalid_argument_attributes.stderr
+++ b/tests/ui/invalid_argument_attributes.stderr
@@ -26,4 +26,4 @@ error: `from_py_with` may only be specified once per argument
   --> tests/ui/invalid_argument_attributes.rs:16:56
    |
 16 | fn from_py_with_repeated(#[pyo3(from_py_with = "func", from_py_with = "func")] _param: String) {}
-   |                                                        ^^^^^^^^^^^^
+   |                                                        ^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/invalid_cancel_handle.stderr b/tests/ui/invalid_cancel_handle.stderr
index bd2b588..0f68dfd 100644
--- a/tests/ui/invalid_cancel_handle.stderr
+++ b/tests/ui/invalid_cancel_handle.stderr
@@ -42,7 +42,7 @@ error[E0277]: the trait bound `CancelHandle: PyFunctionArgument<'_, '_>` is not
   --> tests/ui/invalid_cancel_handle.rs:20:50
    |
 20 | async fn missing_cancel_handle_attribute(_param: pyo3::coroutine::CancelHandle) {}
-   |                                                  ^^^^ the trait `PyClass` is not implemented for `CancelHandle`, which is required by `CancelHandle: PyFunctionArgument<'_, '_>`
+   |                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `PyClass` is not implemented for `CancelHandle`
    |
    = help: the trait `PyClass` is implemented for `pyo3::coroutine::Coroutine`
    = note: required for `CancelHandle` to implement `FromPyObject<'_>`
@@ -61,7 +61,7 @@ error[E0277]: the trait bound `CancelHandle: PyFunctionArgument<'_, '_>` is not
   --> tests/ui/invalid_cancel_handle.rs:20:50
    |
 20 | async fn missing_cancel_handle_attribute(_param: pyo3::coroutine::CancelHandle) {}
-   |                                                  ^^^^ the trait `Clone` is not implemented for `CancelHandle`, which is required by `CancelHandle: PyFunctionArgument<'_, '_>`
+   |                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `CancelHandle`
    |
    = help: the following other types implement trait `PyFunctionArgument<'a, 'py>`:
              &'a mut pyo3::coroutine::Coroutine
diff --git a/tests/ui/invalid_frompy_derive.stderr b/tests/ui/invalid_frompy_derive.stderr
index 8ed03ca..077c315 100644
--- a/tests/ui/invalid_frompy_derive.stderr
+++ b/tests/ui/invalid_frompy_derive.stderr
@@ -130,7 +130,7 @@ error: only one of `attribute` or `item` can be provided
    --> tests/ui/invalid_frompy_derive.rs:118:5
     |
 118 |     #[pyo3(item, attribute)]
-    |     ^
+    |     ^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected one of: `transparent`, `from_item_all`, `annotation`, `crate`
    --> tests/ui/invalid_frompy_derive.rs:123:8
@@ -154,13 +154,15 @@ error: FromPyObject can be derived with at most one lifetime parameter
    --> tests/ui/invalid_frompy_derive.rs:141:22
     |
 141 | enum TooManyLifetimes<'a, 'b> {
-    |                      ^
+    |                      ^^^^^^^^
 
 error: #[derive(FromPyObject)] is not supported for unions
    --> tests/ui/invalid_frompy_derive.rs:147:1
     |
-147 | union Union {
-    | ^^^^^
+147 | / union Union {
+148 | |     a: usize,
+149 | | }
+    | |_^
 
 error: cannot derive FromPyObject for empty structs and variants
    --> tests/ui/invalid_frompy_derive.rs:151:10
@@ -186,7 +188,7 @@ error: `getter` is not permitted on tuple struct elements.
    --> tests/ui/invalid_frompy_derive.rs:169:27
     |
 169 | struct InvalidTupleGetter(#[pyo3(item("foo"))] String);
-    |                           ^
+    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `transparent` structs may not have a `getter` for the inner field
    --> tests/ui/invalid_frompy_derive.rs:175:5
diff --git a/tests/ui/invalid_frozen_pyclass_borrow.stderr b/tests/ui/invalid_frozen_pyclass_borrow.stderr
index 52a0623..705dad2 100644
--- a/tests/ui/invalid_frozen_pyclass_borrow.stderr
+++ b/tests/ui/invalid_frozen_pyclass_borrow.stderr
@@ -8,7 +8,7 @@ error[E0271]: type mismatch resolving `<Foo as PyClass>::Frozen == False`
   --> tests/ui/invalid_frozen_pyclass_borrow.rs:11:19
    |
 11 |     fn mut_method(&mut self) {}
-   |                   ^ expected `False`, found `True`
+   |                   ^^^^^^^^^ expected `False`, found `True`
    |
 note: required by a bound in `extract_pyclass_ref_mut`
   --> src/impl_/extract_argument.rs
diff --git a/tests/ui/invalid_intopy_derive.stderr b/tests/ui/invalid_intopy_derive.stderr
index cf125d9..050612b 100644
--- a/tests/ui/invalid_intopy_derive.stderr
+++ b/tests/ui/invalid_intopy_derive.stderr
@@ -93,8 +93,10 @@ error: expected `transparent` or `crate`
 error: #[derive(`IntoPyObject`)] is not supported for unions
   --> tests/ui/invalid_intopy_derive.rs:81:1
    |
-81 | union Union {
-   | ^^^^^
+81 | / union Union {
+82 | |     a: usize,
+83 | | }
+   | |_^
 
 error: cannot derive `IntoPyObject` for empty variants
   --> tests/ui/invalid_intopy_derive.rs:87:5
diff --git a/tests/ui/invalid_property_args.stderr b/tests/ui/invalid_property_args.stderr
index f2fea2a..e1bdea7 100644
--- a/tests/ui/invalid_property_args.stderr
+++ b/tests/ui/invalid_property_args.stderr
@@ -38,7 +38,7 @@ error: `name` may only be specified once
   --> tests/ui/invalid_property_args.rs:37:42
    |
 37 | struct MultipleName(#[pyo3(name = "foo", name = "bar")] i32);
-   |                                          ^^^^
+   |                                          ^^^^^^^^^^^^
 
 error: `name` is useless without `get` or `set`
   --> tests/ui/invalid_property_args.rs:40:33
@@ -50,9 +50,9 @@ error[E0277]: `PhantomData<i32>` cannot be converted to a Python object
   --> tests/ui/invalid_property_args.rs:45:12
    |
 45 |     value: ::std::marker::PhantomData<i32>,
-   |            ^ required by `#[pyo3(get)]` to create a readable property from a field of type `PhantomData<i32>`
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by `#[pyo3(get)]` to create a readable property from a field of type `PhantomData<i32>`
    |
-   = help: the trait `IntoPyObject<'_>` is not implemented for `PhantomData<i32>`, which is required by `for<'py> PhantomData<i32>: PyO3GetField<'py>`
+   = help: the trait `IntoPyObject<'_>` is not implemented for `PhantomData<i32>`
    = note: implement `IntoPyObject` for `&PhantomData<i32>` or `IntoPyObject + Clone` for `PhantomData<i32>` to define the conversion
    = help: the following other types implement trait `IntoPyObject<'py>`:
              &&'a T
diff --git a/tests/ui/invalid_pyclass_args.stderr b/tests/ui/invalid_pyclass_args.stderr
index 15aa038..8abdeb0 100644
--- a/tests/ui/invalid_pyclass_args.stderr
+++ b/tests/ui/invalid_pyclass_args.stderr
@@ -100,67 +100,77 @@ error: expected one of: `get`, `set`, `name`
 85 |     #[pyo3(pop)]
    |            ^^^
 
-error: invalid format string: expected `'}'` but string was terminated
+error: invalid format string: expected `}` but string was terminated
    --> tests/ui/invalid_pyclass_args.rs:105:19
     |
 105 | #[pyclass(str = "{")]
-    |                  -^ expected `'}'` in format string
+    |                  -^ expected `}` in format string
     |                  |
     |                  because of this opening brace
     |
     = note: if you intended to print `{`, you can escape it using `{{`
 
-error: invalid format string: expected `'}'`, found `'$'`
+error: invalid format string: expected `}`, found `$`
    --> tests/ui/invalid_pyclass_args.rs:109:19
     |
 109 | #[pyclass(str = "{$}")]
-    |                  -^ expected `'}'` in format string
+    |                  -^ expected `}` in format string
     |                  |
     |                  because of this opening brace
     |
     = note: if you intended to print `{`, you can escape it using `{{`
 
 error: The format string syntax is incompatible with any renaming via `name` or `rename_all`
-   --> tests/ui/invalid_pyclass_args.rs:133:31
+   --> tests/ui/invalid_pyclass_args.rs:133:1
     |
 133 | #[pyclass(name = "aaa", str = "unsafe: {unsafe_variable}")]
-    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    |
+    = note: this error originates in the attribute macro `pyclass` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: The format string syntax is incompatible with any renaming via `name` or `rename_all`
-   --> tests/ui/invalid_pyclass_args.rs:139:31
+   --> tests/ui/invalid_pyclass_args.rs:139:1
     |
 139 | #[pyclass(name = "aaa", str = "unsafe: {unsafe_variable}")]
-    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    |
+    = note: this error originates in the attribute macro `pyclass` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: The format string syntax is incompatible with any renaming via `name` or `rename_all`
-   --> tests/ui/invalid_pyclass_args.rs:144:17
+   --> tests/ui/invalid_pyclass_args.rs:144:1
     |
 144 | #[pyclass(str = "unsafe: {unsafe_variable}")]
-    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    |
+    = note: this error originates in the attribute macro `pyclass` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: The format string syntax is incompatible with any renaming via `name` or `rename_all`
-   --> tests/ui/invalid_pyclass_args.rs:150:54
+   --> tests/ui/invalid_pyclass_args.rs:150:1
     |
 150 | #[pyclass(rename_all = "SCREAMING_SNAKE_CASE", str = "{a_a}, {b_b}, {c_d_e}")]
-    |                                                      ^^^^^^^^^^^^^^^^^^^^^^^
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    |
+    = note: this error originates in the attribute macro `pyclass` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: No member found, you must provide a named or positionally specified member.
-   --> tests/ui/invalid_pyclass_args.rs:157:17
+   --> tests/ui/invalid_pyclass_args.rs:157:19
     |
 157 | #[pyclass(str = "{:?}")]
-    |                 ^^^^^^
+    |                   ^
 
 error: No member found, you must provide a named or positionally specified member.
-   --> tests/ui/invalid_pyclass_args.rs:164:17
+   --> tests/ui/invalid_pyclass_args.rs:164:19
     |
 164 | #[pyclass(str = "{}")]
-    |                 ^^^^
+    |                   ^
 
 error: The format string syntax cannot be used with enums
-   --> tests/ui/invalid_pyclass_args.rs:171:21
+   --> tests/ui/invalid_pyclass_args.rs:171:1
     |
 171 | #[pyclass(eq, str = "Stuff...")]
-    |                     ^^^^^^^^^^
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    |
+    = note: this error originates in the attribute macro `pyclass` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0592]: duplicate definitions with name `__pymethod___richcmp____`
   --> tests/ui/invalid_pyclass_args.rs:37:1
@@ -350,25 +360,25 @@ note: candidate #2 is defined in an impl for the type `StrOptAndManualStr`
    = note: this error originates in the attribute macro `pymethods` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0609]: no field `aaaa` on type `&Point`
-   --> tests/ui/invalid_pyclass_args.rs:113:17
+   --> tests/ui/invalid_pyclass_args.rs:113:22
     |
 113 | #[pyclass(str = "X: {aaaa}, Y: {y}, Z: {z}")]
-    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^ unknown field
+    |                      ^^^^ unknown field
     |
     = note: available fields are: `x`, `y`, `z`
 
 error[E0609]: no field `zzz` on type `&Point2`
-   --> tests/ui/invalid_pyclass_args.rs:121:17
+   --> tests/ui/invalid_pyclass_args.rs:121:40
     |
 121 | #[pyclass(str = "X: {x}, Y: {y}}}, Z: {zzz}")]
-    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unknown field
+    |                                        ^^^ unknown field
     |
     = note: available fields are: `x`, `y`, `z`
 
 error[E0609]: no field `162543` on type `&Coord3`
-   --> tests/ui/invalid_pyclass_args.rs:129:17
+   --> tests/ui/invalid_pyclass_args.rs:129:24
     |
 129 | #[pyclass(str = "{0}, {162543}, {2}")]
-    |                 ^^^^^^^^^^^^^^^^^^^^ unknown field
+    |                        ^^^^^^ unknown field
     |
     = note: available fields are: `0`, `1`, `2`
diff --git a/tests/ui/invalid_pyclass_enum.stderr b/tests/ui/invalid_pyclass_enum.stderr
index 80dc953..aefecc1 100644
--- a/tests/ui/invalid_pyclass_enum.stderr
+++ b/tests/ui/invalid_pyclass_enum.stderr
@@ -8,7 +8,7 @@ error: enums can't extend from other classes
  --> tests/ui/invalid_pyclass_enum.rs:9:11
   |
 9 | #[pyclass(extends = PyList)]
-  |           ^^^^^^^
+  |           ^^^^^^^^^^^^^^^^
 
 error: #[pyclass] can't be used on enums without any variants
   --> tests/ui/invalid_pyclass_enum.rs:16:18
@@ -28,7 +28,7 @@ error: `constructor` can't be used on a simple enum variant
   --> tests/ui/invalid_pyclass_enum.rs:26:12
    |
 26 |     #[pyo3(constructor = (a, b))]
-   |            ^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^^^^^^
 
 error: The `eq_int` option requires the `eq` option.
   --> tests/ui/invalid_pyclass_enum.rs:43:11
diff --git a/tests/ui/invalid_pyfunction_definition.stderr b/tests/ui/invalid_pyfunction_definition.stderr
index 9c7cac1..7567eb1 100644
--- a/tests/ui/invalid_pyfunction_definition.stderr
+++ b/tests/ui/invalid_pyfunction_definition.stderr
@@ -2,4 +2,4 @@ error: functions inside #[pymethods] do not need to be annotated with #[pyfuncti
   --> tests/ui/invalid_pyfunction_definition.rs:11:9
    |
 11 |         fn bug() {}
-   |         ^^
+   |         ^^^^^^^^
diff --git a/tests/ui/invalid_pyfunction_signatures.stderr b/tests/ui/invalid_pyfunction_signatures.stderr
index 97d0fd3..bde9af2 100644
--- a/tests/ui/invalid_pyfunction_signatures.stderr
+++ b/tests/ui/invalid_pyfunction_signatures.stderr
@@ -26,7 +26,7 @@ error: `*args` not allowed after `*`
   --> tests/ui/invalid_pyfunction_signatures.rs:25:24
    |
 25 | #[pyo3(signature = (*, *args))]
-   |                        ^
+   |                        ^^^^^
 
 error: `*` not allowed after `*`
   --> tests/ui/invalid_pyfunction_signatures.rs:31:24
@@ -38,13 +38,13 @@ error: `*args` not allowed after `**kwargs`
   --> tests/ui/invalid_pyfunction_signatures.rs:35:31
    |
 35 | #[pyo3(signature = (**kwargs, *args))]
-   |                               ^
+   |                               ^^^^^
 
 error: `**kwargs_b` not allowed after `**kwargs_a`
   --> tests/ui/invalid_pyfunction_signatures.rs:42:33
    |
 42 | #[pyo3(signature = (**kwargs_a, **kwargs_b))]
-   |                                 ^
+   |                                 ^^^^^^^^^^
 
 error: arguments of type `Python` must not be part of the signature
   --> tests/ui/invalid_pyfunction_signatures.rs:48:27
diff --git a/tests/ui/invalid_pyfunctions.stderr b/tests/ui/invalid_pyfunctions.stderr
index 271c5a8..99f38ef 100644
--- a/tests/ui/invalid_pyfunctions.stderr
+++ b/tests/ui/invalid_pyfunctions.stderr
@@ -8,7 +8,7 @@ error: Python functions cannot have `impl Trait` arguments
  --> tests/ui/invalid_pyfunctions.rs:8:37
   |
 8 | fn impl_trait_function(_impl_trait: impl AsRef<PyAny>) {}
-  |                                     ^^^^
+  |                                     ^^^^^^^^^^^^^^^^^
 
 error: wildcard argument names are not supported
   --> tests/ui/invalid_pyfunctions.rs:11:22
@@ -44,7 +44,7 @@ error[E0277]: the trait bound `&str: From<BoundRef<'_, '_, pyo3::types::PyModule
   --> tests/ui/invalid_pyfunctions.rs:33:14
    |
 33 |     _string: &str,
-   |              ^ the trait `From<BoundRef<'_, '_, pyo3::types::PyModule>>` is not implemented for `&str`, which is required by `BoundRef<'_, '_, pyo3::types::PyModule>: Into<_>`
+   |              ^^^^ the trait `From<BoundRef<'_, '_, pyo3::types::PyModule>>` is not implemented for `&str`
    |
    = help: the following other types implement trait `From<T>`:
              `String` implements `From<&String>`
diff --git a/tests/ui/invalid_pymethod_enum.stderr b/tests/ui/invalid_pymethod_enum.stderr
index bc377d2..243eab9 100644
--- a/tests/ui/invalid_pymethod_enum.stderr
+++ b/tests/ui/invalid_pymethod_enum.stderr
@@ -2,7 +2,7 @@ error[E0271]: type mismatch resolving `<ComplexEnum as PyClass>::Frozen == False
   --> tests/ui/invalid_pymethod_enum.rs:11:24
    |
 11 |     fn mutate_in_place(&mut self) {
-   |                        ^ expected `False`, found `True`
+   |                        ^^^^^^^^^ expected `False`, found `True`
    |
 note: required by a bound in `extract_pyclass_ref_mut`
   --> src/impl_/extract_argument.rs
@@ -27,7 +27,7 @@ error[E0271]: type mismatch resolving `<TupleEnum as PyClass>::Frozen == False`
   --> tests/ui/invalid_pymethod_enum.rs:27:24
    |
 27 |     fn mutate_in_place(&mut self) {
-   |                        ^ expected `False`, found `True`
+   |                        ^^^^^^^^^ expected `False`, found `True`
    |
 note: required by a bound in `extract_pyclass_ref_mut`
   --> src/impl_/extract_argument.rs
diff --git a/tests/ui/invalid_pymethod_names.stderr b/tests/ui/invalid_pymethod_names.stderr
index 1e7a6f4..7ded46d 100644
--- a/tests/ui/invalid_pymethod_names.stderr
+++ b/tests/ui/invalid_pymethod_names.stderr
@@ -8,7 +8,7 @@ error: `name` may only be specified once
   --> tests/ui/invalid_pymethod_names.rs:18:12
    |
 18 |     #[pyo3(name = "bar")]
-   |            ^^^^
+   |            ^^^^^^^^^^^^
 
 error: `name` not allowed with `#[new]`
   --> tests/ui/invalid_pymethod_names.rs:24:19
diff --git a/tests/ui/invalid_pymethod_receiver.stderr b/tests/ui/invalid_pymethod_receiver.stderr
index 9c99840..7d81c0f 100644
--- a/tests/ui/invalid_pymethod_receiver.stderr
+++ b/tests/ui/invalid_pymethod_receiver.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `i32: TryFrom<BoundRef<'_, '_, MyClass>>` is not s
  --> tests/ui/invalid_pymethod_receiver.rs:8:44
   |
 8 |     fn method_with_invalid_self_type(_slf: i32, _py: Python<'_>, _index: u32) {}
-  |                                            ^^^ the trait `From<BoundRef<'_, '_, MyClass>>` is not implemented for `i32`, which is required by `i32: TryFrom<BoundRef<'_, '_, MyClass>>`
+  |                                            ^^^ the trait `From<BoundRef<'_, '_, MyClass>>` is not implemented for `i32`
   |
   = help: the following other types implement trait `From<T>`:
             `i32` implements `From<bool>`
diff --git a/tests/ui/invalid_pymethods.stderr b/tests/ui/invalid_pymethods.stderr
index 845b79e..7bd471c 100644
--- a/tests/ui/invalid_pymethods.stderr
+++ b/tests/ui/invalid_pymethods.stderr
@@ -8,19 +8,19 @@ error: `#[classattr]` does not take any arguments
   --> tests/ui/invalid_pymethods.rs:14:5
    |
 14 |     #[classattr(foobar)]
-   |     ^
+   |     ^^^^^^^^^^^^^^^^^^^^
 
 error: static method needs #[staticmethod] attribute
   --> tests/ui/invalid_pymethods.rs:20:5
    |
 20 |     fn staticmethod_without_attribute() {}
-   |     ^^
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: unexpected receiver
   --> tests/ui/invalid_pymethods.rs:26:35
    |
 26 |     fn staticmethod_with_receiver(&self) {}
-   |                                   ^
+   |                                   ^^^^^
 
 error: Expected `&Bound<PyType>` or `Py<PyType>` as the first argument to `#[classmethod]`
   --> tests/ui/invalid_pymethods.rs:32:33
@@ -38,19 +38,19 @@ error: expected receiver for `#[getter]`
   --> tests/ui/invalid_pymethods.rs:54:5
    |
 54 |     fn getter_without_receiver() {}
-   |     ^^
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: expected receiver for `#[setter]`
   --> tests/ui/invalid_pymethods.rs:60:5
    |
 60 |     fn setter_without_receiver() {}
-   |     ^^
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: static method needs #[staticmethod] attribute
   --> tests/ui/invalid_pymethods.rs:66:5
    |
 66 |     fn text_signature_on_call() {}
-   |     ^^
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `text_signature` not allowed with `getter`
   --> tests/ui/invalid_pymethods.rs:72:12
@@ -80,7 +80,7 @@ error: `text_signature` may only be specified once
   --> tests/ui/invalid_pymethods.rs:99:12
    |
 99 |     #[pyo3(text_signature = None)]
-   |            ^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^^^^^^^
 
 error: `signature` not allowed with `getter`
    --> tests/ui/invalid_pymethods.rs:106:12
@@ -103,15 +103,21 @@ error: `signature` not allowed with `classattr`
 error: `#[new]` may not be combined with `#[classmethod]` `#[staticmethod]`, `#[classattr]`, `#[getter]`, and `#[setter]`
    --> tests/ui/invalid_pymethods.rs:126:7
     |
-126 |     #[new]
-    |       ^^^
+126 |       #[new]
+    |  _______^
+127 | |     #[classmethod]
+128 | |     #[staticmethod]
+129 | |     #[classattr]
+130 | |     #[getter(x)]
+131 | |     #[setter(x)]
+    | |____________^
 
 error: `#[new]` does not take any arguments
        = help: did you mean `#[new] #[pyo3(signature = ())]`?
    --> tests/ui/invalid_pymethods.rs:137:7
     |
 137 |     #[new(signature = ())]
-    |       ^^^
+    |       ^^^^^^^^^^^^^^^^^^^
 
 error: `#[new]` does not take any arguments
        = note: this was previously accepted and ignored
@@ -125,21 +131,21 @@ error: `#[classmethod]` does not take any arguments
    --> tests/ui/invalid_pymethods.rs:149:7
     |
 149 |     #[classmethod(signature = ())]
-    |       ^^^^^^^^^^^
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `#[staticmethod]` does not take any arguments
        = help: did you mean `#[staticmethod] #[pyo3(signature = ())]`?
    --> tests/ui/invalid_pymethods.rs:155:7
     |
 155 |     #[staticmethod(signature = ())]
-    |       ^^^^^^^^^^^^
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `#[classattr]` does not take any arguments
        = help: did you mean `#[classattr] #[pyo3(signature = ())]`?
    --> tests/ui/invalid_pymethods.rs:161:7
     |
 161 |     #[classattr(signature = ())]
-    |       ^^^^^^^^^
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: Python functions cannot have generic type parameters
    --> tests/ui/invalid_pymethods.rs:167:23
@@ -151,13 +157,13 @@ error: Python functions cannot have `impl Trait` arguments
    --> tests/ui/invalid_pymethods.rs:172:49
     |
 172 |     fn impl_trait_method_first_arg(_impl_trait: impl AsRef<PyAny>) {}
-    |                                                 ^^^^
+    |                                                 ^^^^^^^^^^^^^^^^^
 
 error: Python functions cannot have `impl Trait` arguments
    --> tests/ui/invalid_pymethods.rs:177:57
     |
 177 |     fn impl_trait_method_second_arg(&self, _impl_trait: impl AsRef<PyAny>) {}
-    |                                                         ^^^^
+    |                                                         ^^^^^^^^^^^^^^^^^
 
 error: `pass_module` cannot be used on Python methods
    --> tests/ui/invalid_pymethods.rs:182:12
@@ -177,13 +183,13 @@ error: macros cannot be used as items in `#[pymethods]` impl blocks
    --> tests/ui/invalid_pymethods.rs:197:5
     |
 197 |     macro_invocation!();
-    |     ^^^^^^^^^^^^^^^^
+    |     ^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: the trait bound `i32: From<BoundRef<'_, '_, PyType>>` is not satisfied
   --> tests/ui/invalid_pymethods.rs:46:45
    |
 46 |     fn classmethod_wrong_first_argument(_x: i32) -> Self {
-   |                                             ^^^ the trait `From<BoundRef<'_, '_, PyType>>` is not implemented for `i32`, which is required by `BoundRef<'_, '_, PyType>: Into<_>`
+   |                                             ^^^ the trait `From<BoundRef<'_, '_, PyType>>` is not implemented for `i32`
    |
    = help: the following other types implement trait `From<T>`:
              `i32` implements `From<bool>`
diff --git a/tests/ui/invalid_pymodule_in_root.stderr b/tests/ui/invalid_pymodule_in_root.stderr
index 0615216..e7c62fb 100644
--- a/tests/ui/invalid_pymodule_in_root.stderr
+++ b/tests/ui/invalid_pymodule_in_root.stderr
@@ -5,6 +5,7 @@ error[E0658]: non-inline modules in proc macro input are unstable
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #54727 <https://github.com/rust-lang/rust/issues/54727> for more information
+  = help: add `#![feature(proc_macro_hygiene)]` to the crate attributes to enable
 
 error: `#[pymodule]` can only be used on inline modules
  --> tests/ui/invalid_pymodule_in_root.rs:5:1
diff --git a/tests/ui/invalid_pymodule_trait.stderr b/tests/ui/invalid_pymodule_trait.stderr
index 0b0d46d..9d9916f 100644
--- a/tests/ui/invalid_pymodule_trait.stderr
+++ b/tests/ui/invalid_pymodule_trait.stderr
@@ -1,8 +1,9 @@
 error: `#[pymodule_export]` may only be used on `use` statements
  --> tests/ui/invalid_pymodule_trait.rs:5:5
   |
-5 |     #[pymodule_export]
-  |     ^
+5 | /     #[pymodule_export]
+6 | |     trait Foo {}
+  | |________________^
 
 error: cannot find attribute `pymodule_export` in this scope
  --> tests/ui/invalid_pymodule_trait.rs:5:7
diff --git a/tests/ui/invalid_pymodule_two_pymodule_init.stderr b/tests/ui/invalid_pymodule_two_pymodule_init.stderr
index 8fbd12f..4728a5a 100644
--- a/tests/ui/invalid_pymodule_two_pymodule_init.stderr
+++ b/tests/ui/invalid_pymodule_two_pymodule_init.stderr
@@ -1,5 +1,7 @@
 error: only one `#[pymodule_init]` may be specified
   --> tests/ui/invalid_pymodule_two_pymodule_init.rs:13:5
    |
-13 |     fn init2(_m: &Bound<'_, PyModule>) -> PyResult<()> {
-   |     ^^
+13 | /     fn init2(_m: &Bound<'_, PyModule>) -> PyResult<()> {
+14 | |         Ok(())
+15 | |     }
+   | |_____^
diff --git a/tests/ui/invalid_result_conversion.stderr b/tests/ui/invalid_result_conversion.stderr
index 1866713..c3b8655 100644
--- a/tests/ui/invalid_result_conversion.stderr
+++ b/tests/ui/invalid_result_conversion.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `PyErr: From<MyError>` is not satisfied
   --> tests/ui/invalid_result_conversion.rs:22:25
    |
 22 | fn should_not_work() -> Result<(), MyError> {
-   |                         ^^^^^^ the trait `From<MyError>` is not implemented for `PyErr`, which is required by `MyError: Into<PyErr>`
+   |                         ^^^^^^^^^^^^^^^^^^^ the trait `From<MyError>` is not implemented for `PyErr`
    |
    = help: the following other types implement trait `From<T>`:
              `PyErr` implements `From<AddrParseError>`
diff --git a/tests/ui/not_send.stderr b/tests/ui/not_send.stderr
index 8007c2f..5d05b3d 100644
--- a/tests/ui/not_send.stderr
+++ b/tests/ui/not_send.stderr
@@ -6,7 +6,7 @@ error[E0277]: `*mut pyo3::Python<'static>` cannot be shared between threads safe
   |        |
   |        required by a bound introduced by this call
   |
-  = help: within `pyo3::Python<'_>`, the trait `Sync` is not implemented for `*mut pyo3::Python<'static>`, which is required by `{closure@$DIR/tests/ui/not_send.rs:4:22: 4:24}: Ungil`
+  = help: within `pyo3::Python<'_>`, the trait `Sync` is not implemented for `*mut pyo3::Python<'static>`
 note: required because it appears within the type `PhantomData<*mut pyo3::Python<'static>>`
  --> $RUST/core/src/marker.rs
   |
diff --git a/tests/ui/not_send2.stderr b/tests/ui/not_send2.stderr
index 52a4e6a..eec2b64 100644
--- a/tests/ui/not_send2.stderr
+++ b/tests/ui/not_send2.stderr
@@ -9,7 +9,7 @@ error[E0277]: `*mut pyo3::Python<'static>` cannot be shared between threads safe
 10 | |         });
    | |_________^ `*mut pyo3::Python<'static>` cannot be shared between threads safely
    |
-   = help: within `pyo3::Bound<'_, PyString>`, the trait `Sync` is not implemented for `*mut pyo3::Python<'static>`, which is required by `{closure@$DIR/tests/ui/not_send2.rs:8:26: 8:28}: Ungil`
+   = help: within `pyo3::Bound<'_, PyString>`, the trait `Sync` is not implemented for `*mut pyo3::Python<'static>`
 note: required because it appears within the type `PhantomData<*mut pyo3::Python<'static>>`
   --> $RUST/core/src/marker.rs
    |
diff --git a/tests/ui/pyclass_send.stderr b/tests/ui/pyclass_send.stderr
index 516df06..1623a5b 100644
--- a/tests/ui/pyclass_send.stderr
+++ b/tests/ui/pyclass_send.stderr
@@ -4,7 +4,7 @@ error[E0277]: `*mut c_void` cannot be shared between threads safely
 5 | struct NotSyncNotSend(*mut c_void);
   |        ^^^^^^^^^^^^^^ `*mut c_void` cannot be shared between threads safely
   |
-  = help: within `NotSyncNotSend`, the trait `Sync` is not implemented for `*mut c_void`, which is required by `NotSyncNotSend: Sync`
+  = help: within `NotSyncNotSend`, the trait `Sync` is not implemented for `*mut c_void`
 note: required because it appears within the type `NotSyncNotSend`
  --> tests/ui/pyclass_send.rs:5:8
   |
@@ -25,7 +25,7 @@ error[E0277]: `*mut c_void` cannot be sent between threads safely
 4 | #[pyclass]
   | ^^^^^^^^^^ `*mut c_void` cannot be sent between threads safely
   |
-  = help: within `NotSyncNotSend`, the trait `Send` is not implemented for `*mut c_void`, which is required by `SendablePyClass<NotSyncNotSend>: pyo3::impl_::pyclass::PyClassThreadChecker<NotSyncNotSend>`
+  = help: within `NotSyncNotSend`, the trait `Send` is not implemented for `*mut c_void`
   = help: the trait `pyo3::impl_::pyclass::PyClassThreadChecker<T>` is implemented for `SendablePyClass<T>`
 note: required because it appears within the type `NotSyncNotSend`
  --> tests/ui/pyclass_send.rs:5:8
@@ -46,7 +46,7 @@ error[E0277]: `*mut c_void` cannot be shared between threads safely
 8 | struct SendNotSync(*mut c_void);
   |        ^^^^^^^^^^^ `*mut c_void` cannot be shared between threads safely
   |
-  = help: within `SendNotSync`, the trait `Sync` is not implemented for `*mut c_void`, which is required by `SendNotSync: Sync`
+  = help: within `SendNotSync`, the trait `Sync` is not implemented for `*mut c_void`
 note: required because it appears within the type `SendNotSync`
  --> tests/ui/pyclass_send.rs:8:8
   |
@@ -67,7 +67,7 @@ error[E0277]: `*mut c_void` cannot be sent between threads safely
 11 | #[pyclass]
    | ^^^^^^^^^^ `*mut c_void` cannot be sent between threads safely
    |
-   = help: within `SyncNotSend`, the trait `Send` is not implemented for `*mut c_void`, which is required by `SendablePyClass<SyncNotSend>: pyo3::impl_::pyclass::PyClassThreadChecker<SyncNotSend>`
+   = help: within `SyncNotSend`, the trait `Send` is not implemented for `*mut c_void`
    = help: the trait `pyo3::impl_::pyclass::PyClassThreadChecker<T>` is implemented for `SendablePyClass<T>`
 note: required because it appears within the type `SyncNotSend`
   --> tests/ui/pyclass_send.rs:12:8
@@ -88,7 +88,7 @@ error[E0277]: `*mut c_void` cannot be sent between threads safely
 4 | #[pyclass]
   | ^^^^^^^^^^ `*mut c_void` cannot be sent between threads safely
   |
-  = help: within `NotSyncNotSend`, the trait `Send` is not implemented for `*mut c_void`, which is required by `NotSyncNotSend: Send`
+  = help: within `NotSyncNotSend`, the trait `Send` is not implemented for `*mut c_void`
 note: required because it appears within the type `NotSyncNotSend`
  --> tests/ui/pyclass_send.rs:5:8
   |
@@ -107,7 +107,7 @@ error[E0277]: `*mut c_void` cannot be sent between threads safely
 11 | #[pyclass]
    | ^^^^^^^^^^ `*mut c_void` cannot be sent between threads safely
    |
-   = help: within `SyncNotSend`, the trait `Send` is not implemented for `*mut c_void`, which is required by `SyncNotSend: Send`
+   = help: within `SyncNotSend`, the trait `Send` is not implemented for `*mut c_void`
 note: required because it appears within the type `SyncNotSend`
   --> tests/ui/pyclass_send.rs:12:8
    |
diff --git a/tests/ui/reject_generics.stderr b/tests/ui/reject_generics.stderr
index 47999f3..206d58d 100644
--- a/tests/ui/reject_generics.stderr
+++ b/tests/ui/reject_generics.stderr
@@ -2,7 +2,7 @@ error: #[pyclass] cannot have generic parameters. For an explanation, see https:
  --> tests/ui/reject_generics.rs:4:25
   |
 4 | struct ClassWithGenerics<A> {
-  |                         ^
+  |                         ^^^
 
 error: #[pyclass] cannot have lifetime parameters. For an explanation, see https://pyo3.rs/v0.23.3/class.html#no-lifetime-parameters
  --> tests/ui/reject_generics.rs:9:27
diff --git a/tests/ui/static_ref.stderr b/tests/ui/static_ref.stderr
index 9fe3735..0e9bf96 100644
--- a/tests/ui/static_ref.stderr
+++ b/tests/ui/static_ref.stderr
@@ -30,7 +30,7 @@ error[E0597]: `holder_0` does not live long enough
   | |           `holder_0` dropped here while still borrowed
   | binding `holder_0` declared here
 5 | fn static_ref(list: &'static Bound<'_, PyList>) -> usize {
-  |               ^^^^^^-
+  |               ^^^^^^--------------------------
   |               |     |
   |               |     argument requires that `holder_0` is borrowed for `'static`
   |               borrowed value does not live long enough
diff --git a/tests/ui/traverse.stderr b/tests/ui/traverse.stderr
index 504a6df..ad8346c 100644
--- a/tests/ui/traverse.stderr
+++ b/tests/ui/traverse.stderr
@@ -2,25 +2,25 @@ error: __traverse__ may not take a receiver other than `&self`. Usually, an impl
   --> tests/ui/traverse.rs:10:27
    |
 10 |     fn __traverse__(_slf: PyRef<Self>, _visit: PyVisit) -> Result<(), PyTraverseError> {
-   |                           ^^^^^
+   |                           ^^^^^^^^^^^
 
 error: __traverse__ may not take a receiver other than `&self`. Usually, an implementation of `__traverse__(&self, visit: PyVisit<'_>) -> Result<(), PyTraverseError>` should do nothing but calls to `visit.call`. Most importantly, safe access to the GIL is prohibited inside implementations of `__traverse__`, i.e. `Python::with_gil` will panic.
   --> tests/ui/traverse.rs:20:27
    |
 20 |     fn __traverse__(_slf: PyRefMut<Self>, _visit: PyVisit) -> Result<(), PyTraverseError> {
-   |                           ^^^^^^^^
+   |                           ^^^^^^^^^^^^^^
 
 error: __traverse__ may not take a receiver other than `&self`. Usually, an implementation of `__traverse__(&self, visit: PyVisit<'_>) -> Result<(), PyTraverseError>` should do nothing but calls to `visit.call`. Most importantly, safe access to the GIL is prohibited inside implementations of `__traverse__`, i.e. `Python::with_gil` will panic.
   --> tests/ui/traverse.rs:30:27
    |
 30 |     fn __traverse__(_slf: Bound<'_, Self>, _visit: PyVisit) -> Result<(), PyTraverseError> {
-   |                           ^^^^^
+   |                           ^^^^^^^^^^^^^^^
 
 error: __traverse__ may not take a receiver other than `&self`. Usually, an implementation of `__traverse__(&self, visit: PyVisit<'_>) -> Result<(), PyTraverseError>` should do nothing but calls to `visit.call`. Most importantly, safe access to the GIL is prohibited inside implementations of `__traverse__`, i.e. `Python::with_gil` will panic.
   --> tests/ui/traverse.rs:40:21
    |
 40 |     fn __traverse__(&mut self, _visit: PyVisit) -> Result<(), PyTraverseError> {
-   |                     ^
+   |                     ^^^^^^^^^
 
 error: __traverse__ may not take `Python`. Usually, an implementation of `__traverse__(&self, visit: PyVisit<'_>) -> Result<(), PyTraverseError>` should do nothing but calls to `visit.call`. Most importantly, safe access to the GIL is prohibited inside implementations of `__traverse__`, i.e. `Python::with_gil` will panic.
   --> tests/ui/traverse.rs:60:33

[davidhewitt]

Yep that's very much expected; the UI test suite is heavily coupled to the stable compiler version.

[clin1234]

So how is testing UI errors handled in CI when building against the nightly compiler?

[davidhewitt]

We just set TRYBUILD=overwrite and ignore the fact it changes the test output