type annotations for variable tuple unpacking, better error messages #23664

Job	Run time
ubuntu-20.04 (batch: allowed_failures)	12m 21s
ubuntu-20.04 (batch: 0_3)	19m 31s
ubuntu-20.04 (batch: 1_3)	30m 7s
ubuntu-20.04 (batch: 2_3)	19m 32s
macos-11 (batch: allowed_failures)	16m 15s
macos-11 (batch: 0_3)	27m 17s
macos-11 (batch: 1_3)	36m 50s
macos-11 (batch: 2_3)	27m 38s
	3h 9m 31s

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