Instantiate anonymous types less#7138
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This operates during `instantiateType` to skip instantiation of anonymous types whose declarations are *not* bound by the type mapper that will do the instantation. Unfortunately, it fails for this types and union types, perhaps because these do not have symbols. This types also don't have explicit type parameters, so that may be the reason. For example, for-of30 currently fails.
Each of the methods has a `typeof Class` argument which currently causes an out-of-memory error when compiling a lot of these methods.
Since they have no static side.
Including aliases of intersection types.
| function createUnaryTypeMapper(source: Type, target: Type): TypeMapper { | ||
| return t => t === source ? target : t; | ||
| const mapper = <TypeMapper>(t => t === source ? target : t); | ||
| mapper.mapsType = sym => sym.name === source.symbol.name; |
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Is this like some sort of optimization?
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This is the information that mappers previously did not expose -- which types they map. This is important because hasTypeParametersInScope will now tell its caller whether a type needs to be instantiated by a particular mapper.
This is only partly an optimization, because some of the types for which we now skip instantiation should never be instantiated, like the anonymous typeof ListWrapper types in the generic static functions in the test.
1. Use types directly instead of type's symbol's names. Comparing names was incorrect and bluebird's .d.ts from DefinitelyTyped still hit the bug. 2. Use this-type of classes directly to see whether this-types are mapped.
This is more complicated than the angular example in that it has a lot of generic statics inside a class that is itself generic. The class and functions all use the same name for their type parameters.
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Weird. The linter failed on protocol.d.t.s, which this PR doesn't touch. But only on the push CI build, not the PR one. |
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It's possible you'll need to merge in from master to sync up with some unrelated changes. |
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Are there any specific speed changes you see when compiling tsc with the new version? |
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I haven't looked, except to test on all the RWC projects -- angular2 and bluebird.d.ts both ran out of memory before and now run just fine. But there should be plenty of unneeded instantiations that are no longer happening. I'll try to run some perf tests later. |
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Fixes issue: #7097
This operates during
instantiateTypeto skip instantiation of anonymous types whose declarations are not bound by the type mapper that will do the instantiation.I'm not sure this is the right approach, but I want to get suggestions on the right way to do it so I thought a strawman would help the discussion.