Reject iterable/collection value for positional parameter

Closes gh-31215

spring-jdbc/src/main/java/org/springframework/jdbc/core/simple/DefaultJdbcClient.java

@@ -106,6 +106,7 @@ final class DefaultJdbcClient implements JdbcClient {
 
 		@Override
 		public StatementSpec param(@Nullable Object value) {
+			validateIndexedParamValue(value);
 			this.indexedParams.add(value);
 			return this;
 		}
@@ -115,6 +116,7 @@ final class DefaultJdbcClient implements JdbcClient {
 			if (jdbcIndex < 1) {
 				throw new IllegalArgumentException("Invalid JDBC index: needs to start at 1");
 			}
+			validateIndexedParamValue(value);
 			int index = jdbcIndex - 1;
 			int size = this.indexedParams.size();
 			if (index < size) {
@@ -129,6 +131,14 @@ final class DefaultJdbcClient implements JdbcClient {
 			return this;
 		}
 
+		private void validateIndexedParamValue(@Nullable Object value) {
+			if (value instanceof Iterable) {
+				throw new IllegalArgumentException("Invalid positional parameter value of type Iterable (" +
+						value.getClass().getSimpleName() +
+						"): Parameter expansion is only supported with named parameters.");
+			}
+		}
+
 		@Override
 		public StatementSpec param(int jdbcIndex, @Nullable Object value, int sqlType) {
 			return param(jdbcIndex, new SqlParameterValue(sqlType, value));