[NEW TYPE INFERENCE] Handle aliased nominal types.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77772970
[NEW TYPE INFERENCE] Find all type variables in scope, not just the ones for polymorphic functions.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77781797