=== tests/cases/compiler/contextualSignatureInstatiationCovariance.ts ===
interface Animal { x }
>Animal : Animal, Symbol(Animal, Decl(contextualSignatureInstatiationCovariance.ts, 0, 0))
>x : any, Symbol(x, Decl(contextualSignatureInstatiationCovariance.ts, 0, 18))

interface TallThing { x2 }
>TallThing : TallThing, Symbol(TallThing, Decl(contextualSignatureInstatiationCovariance.ts, 0, 22))
>x2 : any, Symbol(x2, Decl(contextualSignatureInstatiationCovariance.ts, 1, 21))

interface Giraffe extends Animal, TallThing { y }
>Giraffe : Giraffe, Symbol(Giraffe, Decl(contextualSignatureInstatiationCovariance.ts, 1, 26))
>Animal : Animal, Symbol(Animal, Decl(contextualSignatureInstatiationCovariance.ts, 0, 0))
>TallThing : TallThing, Symbol(TallThing, Decl(contextualSignatureInstatiationCovariance.ts, 0, 22))
>y : any, Symbol(y, Decl(contextualSignatureInstatiationCovariance.ts, 2, 45))

var f2: <T extends Giraffe>(x: T, y: T) => void;
>f2 : <T extends Giraffe>(x: T, y: T) => void, Symbol(f2, Decl(contextualSignatureInstatiationCovariance.ts, 4, 3))
>T : T, Symbol(T, Decl(contextualSignatureInstatiationCovariance.ts, 4, 9))
>Giraffe : Giraffe, Symbol(Giraffe, Decl(contextualSignatureInstatiationCovariance.ts, 1, 26))
>x : T, Symbol(x, Decl(contextualSignatureInstatiationCovariance.ts, 4, 28))
>T : T, Symbol(T, Decl(contextualSignatureInstatiationCovariance.ts, 4, 9))
>y : T, Symbol(y, Decl(contextualSignatureInstatiationCovariance.ts, 4, 33))
>T : T, Symbol(T, Decl(contextualSignatureInstatiationCovariance.ts, 4, 9))

var g2: (a: Animal, t: TallThing) => void;
>g2 : (a: Animal, t: TallThing) => void, Symbol(g2, Decl(contextualSignatureInstatiationCovariance.ts, 6, 3))
>a : Animal, Symbol(a, Decl(contextualSignatureInstatiationCovariance.ts, 6, 9))
>Animal : Animal, Symbol(Animal, Decl(contextualSignatureInstatiationCovariance.ts, 0, 0))
>t : TallThing, Symbol(t, Decl(contextualSignatureInstatiationCovariance.ts, 6, 19))
>TallThing : TallThing, Symbol(TallThing, Decl(contextualSignatureInstatiationCovariance.ts, 0, 22))

g2 = f2; // While neither Animal nor TallThing satisfy the constraint, T is at worst a Giraffe and compatible with both via covariance.
>g2 = f2 : <T extends Giraffe>(x: T, y: T) => void
>g2 : (a: Animal, t: TallThing) => void, Symbol(g2, Decl(contextualSignatureInstatiationCovariance.ts, 6, 3))
>f2 : <T extends Giraffe>(x: T, y: T) => void, Symbol(f2, Decl(contextualSignatureInstatiationCovariance.ts, 4, 3))

var h2: (a1: Animal, a2: Animal) => void;
>h2 : (a1: Animal, a2: Animal) => void, Symbol(h2, Decl(contextualSignatureInstatiationCovariance.ts, 9, 3))
>a1 : Animal, Symbol(a1, Decl(contextualSignatureInstatiationCovariance.ts, 9, 9))
>Animal : Animal, Symbol(Animal, Decl(contextualSignatureInstatiationCovariance.ts, 0, 0))
>a2 : Animal, Symbol(a2, Decl(contextualSignatureInstatiationCovariance.ts, 9, 20))
>Animal : Animal, Symbol(Animal, Decl(contextualSignatureInstatiationCovariance.ts, 0, 0))

h2 = f2; // Animal does not satisfy the constraint, but T is at worst a Giraffe and compatible with Animal via covariance.
>h2 = f2 : <T extends Giraffe>(x: T, y: T) => void
>h2 : (a1: Animal, a2: Animal) => void, Symbol(h2, Decl(contextualSignatureInstatiationCovariance.ts, 9, 3))
>f2 : <T extends Giraffe>(x: T, y: T) => void, Symbol(f2, Decl(contextualSignatureInstatiationCovariance.ts, 4, 3))