diff --git a/src/test/ui-fulldeps/session-derive-errors.rs b/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
similarity index 100%
rename from src/test/ui-fulldeps/session-derive-errors.rs
rename to src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
diff --git a/src/test/ui-fulldeps/session-derive-errors.stderr b/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
similarity index 81%
rename from src/test/ui-fulldeps/session-derive-errors.stderr
rename to src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
index a528ae1607f..902d8251576 100644
--- a/src/test/ui-fulldeps/session-derive-errors.stderr
+++ b/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
@@ -1,5 +1,5 @@
 error: `#[derive(SessionDiagnostic)]` can only be used on structs
-  --> $DIR/session-derive-errors.rs:37:1
+  --> $DIR/diagnostic-derive.rs:37:1
    |
 LL | / #[error(code = "E0123", slug = "foo")]
 LL | |
@@ -10,19 +10,19 @@ LL | | }
    | |_^
 
 error: `#[error = ...]` is not a valid `SessionDiagnostic` struct attribute
-  --> $DIR/session-derive-errors.rs:46:1
+  --> $DIR/diagnostic-derive.rs:46:1
    |
 LL | #[error = "E0123"]
    | ^^^^^^^^^^^^^^^^^^
 
 error: `#[nonsense(...)]` is not a valid `SessionDiagnostic` struct attribute
-  --> $DIR/session-derive-errors.rs:51:1
+  --> $DIR/diagnostic-derive.rs:51:1
    |
 LL | #[nonsense(code = "E0123", slug = "foo")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: diagnostic kind not specified
-  --> $DIR/session-derive-errors.rs:51:1
+  --> $DIR/diagnostic-derive.rs:51:1
    |
 LL | / #[nonsense(code = "E0123", slug = "foo")]
 LL | |
@@ -34,13 +34,13 @@ LL | | struct InvalidStructAttr {}
    = help: use the `#[error(...)]` attribute to create an error
 
 error: `#[error("...")]` is not a valid `SessionDiagnostic` struct attribute
-  --> $DIR/session-derive-errors.rs:58:9
+  --> $DIR/diagnostic-derive.rs:58:9
    |
 LL | #[error("E0123")]
    |         ^^^^^^^
 
 error: `slug` not specified
-  --> $DIR/session-derive-errors.rs:58:1
+  --> $DIR/diagnostic-derive.rs:58:1
    |
 LL | / #[error("E0123")]
 LL | |
@@ -51,25 +51,25 @@ LL | | struct InvalidLitNestedAttr {}
    = help: use the `#[error(slug = "...")]` attribute to set this diagnostic's slug
 
 error: `#[error(nonsense)]` is not a valid `SessionDiagnostic` struct attribute
-  --> $DIR/session-derive-errors.rs:64:9
+  --> $DIR/diagnostic-derive.rs:64:9
    |
 LL | #[error(nonsense, code = "E0123", slug = "foo")]
    |         ^^^^^^^^
 
 error: `#[error(nonsense(...))]` is not a valid `SessionDiagnostic` struct attribute
-  --> $DIR/session-derive-errors.rs:69:9
+  --> $DIR/diagnostic-derive.rs:69:9
    |
 LL | #[error(nonsense("foo"), code = "E0123", slug = "foo")]
    |         ^^^^^^^^^^^^^^^
 
 error: `#[error(nonsense = ...)]` is not a valid `SessionDiagnostic` struct attribute
-  --> $DIR/session-derive-errors.rs:74:9
+  --> $DIR/diagnostic-derive.rs:74:9
    |
 LL | #[error(nonsense = "...", code = "E0123", slug = "foo")]
    |         ^^^^^^^^^^^^^^^^
 
 error: `#[error(nonsense = ...)]` is not a valid `SessionDiagnostic` struct attribute
-  --> $DIR/session-derive-errors.rs:79:9
+  --> $DIR/diagnostic-derive.rs:79:9
    |
 LL | #[error(nonsense = 4, code = "E0123", slug = "foo")]
    |         ^^^^^^^^^^^^
@@ -77,61 +77,61 @@ LL | #[error(nonsense = 4, code = "E0123", slug = "foo")]
    = help: value must be a string
 
 error: `#[suggestion = ...]` is not a valid `SessionDiagnostic` field attribute
-  --> $DIR/session-derive-errors.rs:86:5
+  --> $DIR/diagnostic-derive.rs:86:5
    |
 LL |     #[suggestion = "bar"]
    |     ^^^^^^^^^^^^^^^^^^^^^
 
 error: `error` specified multiple times
-  --> $DIR/session-derive-errors.rs:93:1
+  --> $DIR/diagnostic-derive.rs:93:1
    |
 LL | #[error(code = "E0456", slug = "bar")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 note: previously specified here
-  --> $DIR/session-derive-errors.rs:92:1
+  --> $DIR/diagnostic-derive.rs:92:1
    |
 LL | #[error(code = "E0123", slug = "foo")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `warning` specified when `error` was already specified
-  --> $DIR/session-derive-errors.rs:98:1
+  --> $DIR/diagnostic-derive.rs:98:1
    |
 LL | #[warning(code = "E0293", slug = "bar")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 note: previously specified here
-  --> $DIR/session-derive-errors.rs:97:1
+  --> $DIR/diagnostic-derive.rs:97:1
    |
 LL | #[error(code = "E0123", slug = "foo")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `code` specified multiple times
-  --> $DIR/session-derive-errors.rs:103:32
+  --> $DIR/diagnostic-derive.rs:103:32
    |
 LL | #[error(code = "E0456", code = "E0457", slug = "bar")]
    |                                ^^^^^^^
    |
 note: previously specified here
-  --> $DIR/session-derive-errors.rs:103:16
+  --> $DIR/diagnostic-derive.rs:103:16
    |
 LL | #[error(code = "E0456", code = "E0457", slug = "bar")]
    |                ^^^^^^^
 
 error: `slug` specified multiple times
-  --> $DIR/session-derive-errors.rs:107:46
+  --> $DIR/diagnostic-derive.rs:107:46
    |
 LL | #[error(code = "E0456", slug = "foo", slug = "bar")]
    |                                              ^^^^^
    |
 note: previously specified here
-  --> $DIR/session-derive-errors.rs:107:32
+  --> $DIR/diagnostic-derive.rs:107:32
    |
 LL | #[error(code = "E0456", slug = "foo", slug = "bar")]
    |                                ^^^^^
 
 error: diagnostic kind not specified
-  --> $DIR/session-derive-errors.rs:111:1
+  --> $DIR/diagnostic-derive.rs:111:1
    |
 LL | struct KindNotProvided {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -139,7 +139,7 @@ LL | struct KindNotProvided {}
    = help: use the `#[error(...)]` attribute to create an error
 
 error: `slug` not specified
-  --> $DIR/session-derive-errors.rs:114:1
+  --> $DIR/diagnostic-derive.rs:114:1
    |
 LL | / #[error(code = "E0456")]
 LL | | struct SlugNotProvided {}
@@ -148,31 +148,31 @@ LL | | struct SlugNotProvided {}
    = help: use the `#[error(slug = "...")]` attribute to set this diagnostic's slug
 
 error: the `#[primary_span]` attribute can only be applied to fields of type `Span`
-  --> $DIR/session-derive-errors.rs:124:5
+  --> $DIR/diagnostic-derive.rs:124:5
    |
 LL |     #[primary_span]
    |     ^^^^^^^^^^^^^^^
 
 error: `#[nonsense]` is not a valid `SessionDiagnostic` field attribute
-  --> $DIR/session-derive-errors.rs:132:5
+  --> $DIR/diagnostic-derive.rs:132:5
    |
 LL |     #[nonsense]
    |     ^^^^^^^^^^^
 
 error: the `#[label = ...]` attribute can only be applied to fields of type `Span`
-  --> $DIR/session-derive-errors.rs:149:5
+  --> $DIR/diagnostic-derive.rs:149:5
    |
 LL |     #[label = "bar"]
    |     ^^^^^^^^^^^^^^^^
 
 error: `name` doesn't refer to a field on this type
-  --> $DIR/session-derive-errors.rs:157:42
+  --> $DIR/diagnostic-derive.rs:157:42
    |
 LL |     #[suggestion(message = "bar", code = "{name}")]
    |                                          ^^^^^^^^
 
 error: invalid format string: expected `'}'` but string was terminated
-  --> $DIR/session-derive-errors.rs:162:16
+  --> $DIR/diagnostic-derive.rs:162:16
    |
 LL | #[derive(SessionDiagnostic)]
    |           -    ^ expected `'}'` in format string
@@ -183,7 +183,7 @@ LL | #[derive(SessionDiagnostic)]
    = note: this error originates in the derive macro `SessionDiagnostic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: invalid format string: unmatched `}` found
-  --> $DIR/session-derive-errors.rs:172:15
+  --> $DIR/diagnostic-derive.rs:172:15
    |
 LL | #[derive(SessionDiagnostic)]
    |               ^ unmatched `}` in format string
@@ -192,25 +192,25 @@ LL | #[derive(SessionDiagnostic)]
    = note: this error originates in the derive macro `SessionDiagnostic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: the `#[label = ...]` attribute can only be applied to fields of type `Span`
-  --> $DIR/session-derive-errors.rs:192:5
+  --> $DIR/diagnostic-derive.rs:192:5
    |
 LL |     #[label = "bar"]
    |     ^^^^^^^^^^^^^^^^
 
 error: `#[suggestion(nonsense = ...)]` is not a valid `SessionDiagnostic` field attribute
-  --> $DIR/session-derive-errors.rs:217:18
+  --> $DIR/diagnostic-derive.rs:217:18
    |
 LL |     #[suggestion(nonsense = "bar")]
    |                  ^^^^^^^^^^^^^^^^
 
 error: `#[suggestion(msg = ...)]` is not a valid `SessionDiagnostic` field attribute
-  --> $DIR/session-derive-errors.rs:225:18
+  --> $DIR/diagnostic-derive.rs:225:18
    |
 LL |     #[suggestion(msg = "bar")]
    |                  ^^^^^^^^^^^
 
 error: wrong field type for suggestion
-  --> $DIR/session-derive-errors.rs:247:5
+  --> $DIR/diagnostic-derive.rs:247:5
    |
 LL | /     #[suggestion(message = "bar", code = "This is suggested code")]
 LL | |
@@ -220,7 +220,7 @@ LL | |     suggestion: Applicability,
    = help: `#[suggestion(...)]` should be applied to fields of type `Span` or `(Span, Applicability)`
 
 error: type of field annotated with `#[suggestion(...)]` contains more than one `Span`
-  --> $DIR/session-derive-errors.rs:262:5
+  --> $DIR/diagnostic-derive.rs:262:5
    |
 LL | /     #[suggestion(message = "bar", code = "This is suggested code")]
 LL | |
@@ -228,7 +228,7 @@ LL | |     suggestion: (Span, Span, Applicability),
    | |___________________________________________^
 
 error: type of field annotated with `#[suggestion(...)]` contains more than one Applicability
-  --> $DIR/session-derive-errors.rs:270:5
+  --> $DIR/diagnostic-derive.rs:270:5
    |
 LL | /     #[suggestion(message = "bar", code = "This is suggested code")]
 LL | |
@@ -236,49 +236,49 @@ LL | |     suggestion: (Applicability, Applicability, Span),
    | |____________________________________________________^
 
 error: `#[label(...)]` is not a valid `SessionDiagnostic` field attribute
-  --> $DIR/session-derive-errors.rs:278:5
+  --> $DIR/diagnostic-derive.rs:278:5
    |
 LL |     #[label("bar")]
    |     ^^^^^^^^^^^^^^^
 
 error: `#[help]` must come after `#[error(..)]` or `#[warn(..)]`
-  --> $DIR/session-derive-errors.rs:399:1
+  --> $DIR/diagnostic-derive.rs:399:1
    |
 LL | #[help]
    | ^^^^^^^
 
 error: `#[help = ...]` must come after `#[error(..)]` or `#[warn(..)]`
-  --> $DIR/session-derive-errors.rs:407:1
+  --> $DIR/diagnostic-derive.rs:407:1
    |
 LL | #[help = "bar"]
    | ^^^^^^^^^^^^^^^
 
 error: `#[note]` must come after `#[error(..)]` or `#[warn(..)]`
-  --> $DIR/session-derive-errors.rs:415:1
+  --> $DIR/diagnostic-derive.rs:415:1
    |
 LL | #[note]
    | ^^^^^^^
 
 error: `#[note = ...]` must come after `#[error(..)]` or `#[warn(..)]`
-  --> $DIR/session-derive-errors.rs:423:1
+  --> $DIR/diagnostic-derive.rs:423:1
    |
 LL | #[note = "bar"]
    | ^^^^^^^^^^^^^^^
 
 error: cannot find attribute `nonsense` in this scope
-  --> $DIR/session-derive-errors.rs:51:3
+  --> $DIR/diagnostic-derive.rs:51:3
    |
 LL | #[nonsense(code = "E0123", slug = "foo")]
    |   ^^^^^^^^
 
 error: cannot find attribute `nonsense` in this scope
-  --> $DIR/session-derive-errors.rs:132:7
+  --> $DIR/diagnostic-derive.rs:132:7
    |
 LL |     #[nonsense]
    |       ^^^^^^^^
 
 error[E0599]: no method named `into_diagnostic_arg` found for struct `Hello` in the current scope
-  --> $DIR/session-derive-errors.rs:322:10
+  --> $DIR/diagnostic-derive.rs:322:10
    |
 LL | struct Hello {}
    | ------------ method `into_diagnostic_arg` not found for this