diff --git a/crates/red_knot_python_semantic/src/types/context.rs b/crates/red_knot_python_semantic/src/types/context.rs
index 3e7a47b1ed..c5ed58dbc6 100644
--- a/crates/red_knot_python_semantic/src/types/context.rs
+++ b/crates/red_knot_python_semantic/src/types/context.rs
@@ -59,11 +59,8 @@ impl<'db> InferContext<'db> {
         self.db
     }
 
-    pub(crate) fn extend<T>(&mut self, other: &T)
-    where
-        T: WithDiagnostics,
-    {
-        self.diagnostics.get_mut().extend(other.diagnostics());
+    pub(crate) fn extend(&mut self, other: &TypeCheckDiagnostics) {
+        self.diagnostics.get_mut().extend(other);
     }
 
     /// Reports a lint located at `ranged`.
@@ -223,7 +220,3 @@ pub(crate) enum InNoTypeCheck {
     /// The inference is known to be in an `@no_type_check` decorated function.
     Yes,
 }
-
-pub(crate) trait WithDiagnostics {
-    fn diagnostics(&self) -> &TypeCheckDiagnostics;
-}
diff --git a/crates/red_knot_python_semantic/src/types/infer.rs b/crates/red_knot_python_semantic/src/types/infer.rs
index 3eefb1112c..4ee4d8a55a 100644
--- a/crates/red_knot_python_semantic/src/types/infer.rs
+++ b/crates/red_knot_python_semantic/src/types/infer.rs
@@ -88,7 +88,7 @@ use crate::util::subscript::{PyIndex, PySlice};
 use crate::Db;
 
 use super::class_base::ClassBase;
-use super::context::{InNoTypeCheck, InferContext, WithDiagnostics};
+use super::context::{InNoTypeCheck, InferContext};
 use super::diagnostic::{
     report_index_out_of_bounds, report_invalid_exception_caught, report_invalid_exception_cause,
     report_invalid_exception_raised, report_invalid_type_checking_constant,
@@ -439,12 +439,6 @@ impl<'db> TypeInference<'db> {
     }
 }
 
-impl WithDiagnostics for TypeInference<'_> {
-    fn diagnostics(&self) -> &TypeCheckDiagnostics {
-        &self.diagnostics
-    }
-}
-
 /// Whether the intersection type is on the left or right side of the comparison.
 #[derive(Debug, Clone, Copy)]
 enum IntersectionOn {
@@ -567,7 +561,7 @@ impl<'db> TypeInferenceBuilder<'db> {
             .extend(inference.declarations.iter());
         self.types.expressions.extend(inference.expressions.iter());
         self.types.deferred.extend(inference.deferred.iter());
-        self.context.extend(inference);
+        self.context.extend(inference.diagnostics());
     }
 
     fn file(&self) -> File {
@@ -1863,7 +1857,7 @@ impl<'db> TypeInferenceBuilder<'db> {
                     let unpacked = infer_unpack_types(self.db(), unpack);
                     let name_ast_id = name.scoped_expression_id(self.db(), self.scope());
                     if unpack_position == UnpackPosition::First {
-                        self.context.extend(unpacked);
+                        self.context.extend(unpacked.diagnostics());
                     }
                     unpacked.expression_type(name_ast_id)
                 }
@@ -2673,7 +2667,7 @@ impl<'db> TypeInferenceBuilder<'db> {
                 // Only copy the diagnostics if this is the first assignment to avoid duplicating the
                 // unpack assignments.
                 if unpack_position == UnpackPosition::First {
-                    self.context.extend(unpacked);
+                    self.context.extend(unpacked.diagnostics());
                 }
 
                 let name_ast_id = name.scoped_expression_id(self.db(), self.scope());
@@ -2973,7 +2967,7 @@ impl<'db> TypeInferenceBuilder<'db> {
                 TargetKind::Sequence(unpack_position, unpack) => {
                     let unpacked = infer_unpack_types(self.db(), unpack);
                     if unpack_position == UnpackPosition::First {
-                        self.context.extend(unpacked);
+                        self.context.extend(unpacked.diagnostics());
                     }
                     let name_ast_id = name.scoped_expression_id(self.db(), self.scope());
                     unpacked.expression_type(name_ast_id)
diff --git a/crates/red_knot_python_semantic/src/types/unpacker.rs b/crates/red_knot_python_semantic/src/types/unpacker.rs
index b70f7913ce..b32218de45 100644
--- a/crates/red_knot_python_semantic/src/types/unpacker.rs
+++ b/crates/red_knot_python_semantic/src/types/unpacker.rs
@@ -11,7 +11,7 @@ use crate::types::{infer_expression_types, todo_type, Type, TypeCheckDiagnostics
 use crate::unpack::{UnpackKind, UnpackValue};
 use crate::Db;
 
-use super::context::{InferContext, WithDiagnostics};
+use super::context::InferContext;
 use super::diagnostic::INVALID_ASSIGNMENT;
 use super::{TupleType, UnionType};
 
@@ -283,10 +283,9 @@ impl<'db> UnpackResult<'db> {
     pub(crate) fn expression_type(&self, expr_id: ScopedExpressionId) -> Type<'db> {
         self.targets[&expr_id]
     }
-}
 
-impl WithDiagnostics for UnpackResult<'_> {
-    fn diagnostics(&self) -> &TypeCheckDiagnostics {
+    /// Returns the diagnostics in this unpacking assignment.
+    pub(crate) fn diagnostics(&self) -> &TypeCheckDiagnostics {
         &self.diagnostics
     }
 }