ruff_db: rename Diagnostic to OldDiagnosticTrait

This trait should eventually go away, so we rename it (and supporting
types) to make room for a new concrete `Diagnostic` type.

This commit is just the rename. In the next commit, we'll move it to a
different module.

crates/red_knot_python_semantic/src/types/call/bind.rs

@@ -6,7 +6,7 @@ use crate::types::diagnostic::{
 };
 use crate::types::signatures::Parameter;
 use crate::types::{todo_type, CallableType, UnionType};
-use ruff_db::diagnostic::{SecondaryDiagnosticMessage, Span};
+use ruff_db::diagnostic::{OldSecondaryDiagnosticMessage, Span};
 use ruff_python_ast as ast;
 use ruff_text_size::Ranged;
 
@@ -388,7 +388,7 @@ impl<'db> CallBindingError<'db> {
                 if let Some(span) =
                     Self::parameter_span_from_index(context.db(), callable_ty, parameter.index)
                 {
-                    messages.push(SecondaryDiagnosticMessage::new(
+                    messages.push(OldSecondaryDiagnosticMessage::new(
                         span,
                         "parameter declared in function definition here",
                     ));

crates/red_knot_python_semantic/src/types/context.rs

@@ -2,7 +2,7 @@ use std::fmt;
 
 use drop_bomb::DebugDropBomb;
 use ruff_db::{
-    diagnostic::{DiagnosticId, SecondaryDiagnosticMessage, Severity},
+    diagnostic::{DiagnosticId, OldSecondaryDiagnosticMessage, Severity},
     files::File,
 };
 use ruff_text_size::{Ranged, TextRange};
@@ -84,7 +84,7 @@ impl<'db> InferContext<'db> {
         lint: &'static LintMetadata,
         ranged: T,
         message: fmt::Arguments,
-        secondary_messages: Vec<SecondaryDiagnosticMessage>,
+        secondary_messages: Vec<OldSecondaryDiagnosticMessage>,
     ) where
         T: Ranged,
     {
@@ -136,7 +136,7 @@ impl<'db> InferContext<'db> {
         id: DiagnosticId,
         severity: Severity,
         message: fmt::Arguments,
-        secondary_messages: Vec<SecondaryDiagnosticMessage>,
+        secondary_messages: Vec<OldSecondaryDiagnosticMessage>,
     ) where
         T: Ranged,
     {

crates/red_knot_python_semantic/src/types/diagnostic.rs

@@ -8,7 +8,9 @@ use crate::types::string_annotation::{
 };
 use crate::types::{ClassLiteralType, KnownInstanceType, Type};
 use crate::{declare_lint, Db};
-use ruff_db::diagnostic::{Diagnostic, DiagnosticId, SecondaryDiagnosticMessage, Severity, Span};
+use ruff_db::diagnostic::{
+    DiagnosticId, OldDiagnosticTrait, OldSecondaryDiagnosticMessage, Severity, Span,
+};
 use ruff_db::files::File;
 use ruff_python_ast::{self as ast, AnyNodeRef};
 use ruff_text_size::TextRange;
@@ -828,7 +830,7 @@ pub struct TypeCheckDiagnostic {
     pub(crate) range: TextRange,
     pub(crate) severity: Severity,
     pub(crate) file: File,
-    pub(crate) secondary_messages: Vec<SecondaryDiagnosticMessage>,
+    pub(crate) secondary_messages: Vec<OldSecondaryDiagnosticMessage>,
 }
 
 impl TypeCheckDiagnostic {
@@ -845,7 +847,7 @@ impl TypeCheckDiagnostic {
     }
 }
 
-impl Diagnostic for TypeCheckDiagnostic {
+impl OldDiagnosticTrait for TypeCheckDiagnostic {
     fn id(&self) -> DiagnosticId {
         self.id
     }
@@ -858,7 +860,7 @@ impl Diagnostic for TypeCheckDiagnostic {
         Some(Span::from(self.file).with_range(self.range))
     }
 
-    fn secondary_messages(&self) -> &[SecondaryDiagnosticMessage] {
+    fn secondary_messages(&self) -> &[OldSecondaryDiagnosticMessage] {
         &self.secondary_messages
     }