Fixed #36042 -- Raised ValueError when using CompositePrimaryKey as rhs.

2 files changed, 7 insertions, 1 deletions

diff --git a/django/db/models/expressions.py b/django/db/models/expressions.py
index 667e9f93c6..88c5596c17 100644
--- a/django/db/models/expressions.py
+++ b/django/db/models/expressions.py
@@ -758,6 +758,8 @@ class CombinedExpression(SQLiteNumericMixin, Expression):
         rhs = self.rhs.resolve_expression(
             query, allow_joins, reuse, summarize, for_save
         )
+        if isinstance(lhs, ColPairs) or isinstance(rhs, ColPairs):
+            raise ValueError("CompositePrimaryKey is not combinable.")
         if not isinstance(self, (DurationExpression, TemporalSubtraction)):
             try:
                 lhs_type = lhs.output_field.get_internal_type()
diff --git a/django/db/models/lookups.py b/django/db/models/lookups.py
index 734f911f83..56dbdabac1 100644
--- a/django/db/models/lookups.py
+++ b/django/db/models/lookups.py
@@ -4,7 +4,7 @@ import warnings
 
 from django.core.exceptions import EmptyResultSet, FullResultSet
 from django.db.backends.base.operations import BaseDatabaseOperations
-from django.db.models.expressions import Case, Expression, Func, Value, When
+from django.db.models.expressions import Case, ColPairs, Expression, Func, Value, When
 from django.db.models.fields import (
     BooleanField,
     CharField,
@@ -119,6 +119,10 @@ class Lookup(Expression):
             value = value.resolve_expression(compiler.query)
         if hasattr(value, "as_sql"):
             sql, params = compiler.compile(value)
+            if isinstance(value, ColPairs):
+                raise ValueError(
+                    "CompositePrimaryKey cannot be used as a lookup value."
+                )
             # Ensure expression is wrapped in parentheses to respect operator
             # precedence but avoid double wrapping as it can be misinterpreted
             # on some backends (e.g. subqueries on SQLite).