Don't back off to unknown for circular type references
Don't back off to unknown for circular type references

Keeping a NamedType around gives better type checking than backing off
to unknown.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=208538494

google/closure-compiler,vobruba-martin/closure-compiler,google/closure-compiler,google/closure-compiler,monetate/closure-compiler,monetate/closure-compiler,nawawi/closure-compiler,ChadKillingsworth/closure-compiler,google/closure-compiler,Yannic/closure-compiler,ChadKillingsworth/closure-compiler,shantanusharma/closure-compiler,tiobe/closure-compiler,shantanusharma/closure-compiler,shantanusharma/closure-compiler,monetate/closure-compiler,tiobe/closure-compiler,nawawi/closure-compiler,ChadKillingsworth/closure-compiler,vobruba-martin/closure-compiler,Yannic/closure-compiler,nawawi/closure-compiler,vobruba-martin/closure-compiler,tiobe/closure-compiler,ChadKillingsworth/closure-compiler,nawawi/closure-compiler,tiobe/closure-compiler,vobruba-martin/closure-compiler,Yannic/closure-compiler,shantanusharma/closure-compiler,monetate/closure-compiler,Yannic/closure-compiler