EГ
https://www.typescriptlang.org/play?#code/MYGwhgzhAECCB2BLAtmE0DeBfAUKSMAQogE4Am0ApgB4Aul8ZMCKamO0n0wAFqQA4AKAJSZcufFGgBhEgHsA7lToMm0YuXZduYBSLE5cOYwDMArvGC1Ec+NxC3KgkwC5oggEZuNZUQF4APnVSXzcANzlECgwOLhBKWmh+MBIGRL9oeEolH1jOeMSPMA8ATx9oDJNBZNT4WmE86CLSnwA6XgERQxxzS2tbaDAkVBAAFTkfQTA3FhHhbxCtaFTaMxI7LJyQrtxeqxs7YHkFccngN1lFeeDNGM4VtY3sm7Id41BHKeG0U5DRAHp-tAAPIAaTwDiygiOil+5FEOCAA
все же верно получается
(A1 -> B1) :> (A2 -> B2)
если
А1 :> A2
B1 <: B2



