During code generation phase of yang models which contain notification and leafref within the notification, code generator is not able to find leafref which is present in the model.

Example model artifact:
https://git.opendaylight.org/gerrit/#/c/74613/

[ERROR] yang-to-sources: Unable to generate sources with org.opendaylight.mdsal.binding.maven.api.gen.plugin.CodeGeneratorImpl generator
java.lang.IllegalArgumentException: Failed to find leafref target: /hardware/component/state/admin-state in module ietf-hardware (QNameModule{ns=urn:ietf:params:xml:ns:yang:ietf-hardware, rev=2018-03-13}) [org.opendaylight.mdsal.binding.yang.types.CodegenTypeProvider@3b009e7b]
at com.google.common.base.Preconditions.checkArgument (Preconditions.java:474)
at org.opendaylight.mdsal.binding.yang.types.AbstractTypeProvider.provideTypeForLeafref (AbstractTypeProvider.java:566)
at org.opendaylight.mdsal.binding.yang.types.AbstractTypeProvider.javaTypeForLeafrefOrIdentityRef (AbstractTypeProvider.java:318)
at org.opendaylight.mdsal.binding.yang.types.AbstractTypeProvider.javaTypeForSchemaDefinitionType (AbstractTypeProvider.java:212)
at org.opendaylight.mdsal.binding.generator.impl.AbstractTypeGenerator.resolveLeafSchemaNodeAsMethod (AbstractTypeGenerator.java:1366)
at org.opendaylight.mdsal.binding.generator.impl.AbstractTypeGenerator.addSchemaNodeToBuilderAsMethod (AbstractTypeGenerator.java:1063)
at org.opendaylight.mdsal.binding.generator.impl.AbstractTypeGenerator.resolveDataSchemaNodes (AbstractTypeGenerator.java:1000)
at org.opendaylight.mdsal.binding.generator.impl.AbstractTypeGenerator.notificationsToGenType (AbstractTypeGenerator.java:520)
at org.opendaylight.mdsal.binding.generator.impl.AbstractTypeGenerator.moduleToGenTypes (AbstractTypeGenerator.java:207)
at org.opendaylight.mdsal.binding.generator.impl.AbstractTypeGenerator.<init> (AbstractTypeGenerator.java:173)
at org.opendaylight.mdsal.binding.generator.impl.CodegenTypeGenerator.<init> (CodegenTypeGenerator.java:30)
at org.opendaylight.mdsal.binding.generator.impl.BindingGeneratorImpl.generateTypes (BindingGeneratorImpl.java:55)
at org.opendaylight.mdsal.binding.maven.api.gen.plugin.CodeGeneratorImpl.generateSources (CodeGeneratorImpl.java:61)
at org.opendaylight.yangtools.yang2sources.plugin.YangToSourcesProcessor.generateSourcesWithOneGenerator (YangToSourcesProcessor.java:379)
at org.opendaylight.yangtools.yang2sources.plugin.YangToSourcesProcessor.generateSources (YangToSourcesProcessor.java:329)
at org.opendaylight.yangtools.yang2sources.plugin.YangToSourcesProcessor.conditionalExecute (YangToSourcesProcessor.java:156)
at org.opendaylight.yangtools.yang2sources.plugin.YangToSourcesMojo.execute (YangToSourcesMojo.java:123)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:208)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:154)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:146)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
at org.apache.maven.cli.MavenCli.execute (MavenCli.java:956)
at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:290)
at org.apache.maven.cli.MavenCli.main (MavenCli.java:194)
at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke (Method.java:498)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:356)
[ERROR] yang-to-sources: One or more code generators failed, including failed list(generatorClass=exception) {org.opendaylight.mdsal.binding.maven.api.gen.plugin.CodeGeneratorImpl=java.lang.IllegalArgumentException}