=== tests/cases/compiler/targetTypingOnFunctions.ts ===
var fu: (s: string) => string = function (s) { return s.toLowerCase() };
>fu : Symbol(fu, Decl(targetTypingOnFunctions.ts, 0, 3))
>s : Symbol(s, Decl(targetTypingOnFunctions.ts, 0, 9))
>s : Symbol(s, Decl(targetTypingOnFunctions.ts, 0, 42))
>s.toLowerCase : Symbol(String.toLowerCase, Decl(lib.d.ts, 399, 51))
>s : Symbol(s, Decl(targetTypingOnFunctions.ts, 0, 42))
>toLowerCase : Symbol(String.toLowerCase, Decl(lib.d.ts, 399, 51))

var zu = fu = function (s) { return s.toLowerCase() };
>zu : Symbol(zu, Decl(targetTypingOnFunctions.ts, 2, 3))
>fu : Symbol(fu, Decl(targetTypingOnFunctions.ts, 0, 3))
>s : Symbol(s, Decl(targetTypingOnFunctions.ts, 2, 24))
>s.toLowerCase : Symbol(String.toLowerCase, Decl(lib.d.ts, 399, 51))
>s : Symbol(s, Decl(targetTypingOnFunctions.ts, 2, 24))
>toLowerCase : Symbol(String.toLowerCase, Decl(lib.d.ts, 399, 51))