Typedef not resolved properly in deviation

We are currently using Carbon SR1.

When parsing some deviations, we get errors that typedefs can't be resolved, although the model seems correct. I've attached a minimal model showing the error. When parsing that model, we get the following error:

Caused by: org.opendaylight.yangtools.yang.parser.spi.source.SourceException: Cannot resolve QNameModule for 'ex:mytype' [at example-dev:32:12]
at org.opendaylight.yangtools.yang.parser.spi.source.SourceException.throwIf(SourceException.java:97)
at org.opendaylight.yangtools.yang.parser.spi.source.SourceException.throwIfNull(SourceException.java:114)
at org.opendaylight.yangtools.yang.parser.spi.meta.StmtContextUtils.qnameFromArgument(StmtContextUtils.java:524)
at org.opendaylight.yangtools.yang.parser.stmt.rfc6020.TypeStatementImpl$Definition.createEffective(TypeStatementImpl.java:162)
at org.opendaylight.yangtools.yang.parser.stmt.rfc6020.TypeStatementImpl$Definition.createEffective(TypeStatementImpl.java:87)
at org.opendaylight.yangtools.yang.parser.stmt.reactor.StatementContextBase.buildEffective(StatementContextBase.java:415)
at com.google.common.collect.Iterators$8.transform(Iterators.java:799)
at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:48)
at java.util.AbstractCollection.toArray(AbstractCollection.java:141)
at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:258)
at org.opendaylight.yangtools.yang.parser.stmt.rfc6020.effective.EffectiveStatementBase.(EffectiveStatementBase.java:55)
at org.opendaylight.yangtools.yang.parser.stmt.rfc6020.effective.DeclaredEffectiveStatementBase.(DeclaredEffectiveStatementBase.java:31)
at org.opendaylight.yangtools.yang.parser.stmt.rfc6020.effective.AbstractEffectiveDocumentedNode.(AbstractEffectiveDocumentedNode.java:30)