diff --git a/spring-expression/src/main/java/org/springframework/expression/spel/ast/Indexer.java b/spring-expression/src/main/java/org/springframework/expression/spel/ast/Indexer.java
index 9dc12f91fdd0..a56199ad33b5 100644
--- a/spring-expression/src/main/java/org/springframework/expression/spel/ast/Indexer.java
+++ b/spring-expression/src/main/java/org/springframework/expression/spel/ast/Indexer.java
@@ -630,6 +630,8 @@ public void setValue(@Nullable Object newValue) {
 				throw new SpelEvaluationException(getStartPosition(), ex,
 						SpelMessage.EXCEPTION_DURING_PROPERTY_WRITE, this.name, ex.getMessage());
 			}
+			throw new SpelEvaluationException(getStartPosition(),
+					SpelMessage.INDEXING_NOT_SUPPORTED_FOR_TYPE, this.targetObjectTypeDescriptor.toString());
 		}
 
 		@Override
diff --git a/spring-expression/src/test/java/org/springframework/expression/spel/PropertyAccessTests.java b/spring-expression/src/test/java/org/springframework/expression/spel/PropertyAccessTests.java
index 1117882ae561..69f67c32528e 100644
--- a/spring-expression/src/test/java/org/springframework/expression/spel/PropertyAccessTests.java
+++ b/spring-expression/src/test/java/org/springframework/expression/spel/PropertyAccessTests.java
@@ -189,6 +189,10 @@ void propertyReadOnly() {
 		assertThatSpelEvaluationException()
 				.isThrownBy(() -> parser.parseExpression("name='p3'").getValue(context, target))
 				.extracting(SpelEvaluationException::getMessageCode).isEqualTo(SpelMessage.PROPERTY_OR_FIELD_NOT_WRITABLE);
+
+		assertThatSpelEvaluationException()
+				.isThrownBy(() -> parser.parseExpression("['name']='p4'").getValue(context, target))
+				.extracting(SpelEvaluationException::getMessageCode).isEqualTo(SpelMessage.INDEXING_NOT_SUPPORTED_FOR_TYPE);
 	}
 
 	@Test