"let a b c = ..." doesn't suggest other semantics. It's saying: "a applied to b, and then applied to c, equals ...". Note Haskell makes an effort to have the LH

"let a b c = ..." doesn't suggest other semantics. It's saying: "a applied to b, and then applied to c, equals ...". Note Haskell makes an effort to have the LHS of definitions imitate the exact syntax of function application. Patterns use the same syntax as data constructor applications.