Incorrect error messages in enum instantiation

[ironcev]

The following example generates incorrect error messages:

script;

enum MyOption {
    Some: bool,
    None: (),
}

enum MyOtherOption {
    NoSome: bool,
    None: (),
}

main() {
    let _: MyOption = Option::Some(123);
           //                      ^^^ Mismatched types.
           // expected: bool      // WRONG: Expectation is coming from a type that is not `Option`.
           // found:    numeric.
           // help: Enum instantiator must match its declared variant type.

    let _: MyOtherOption = Option::Some(123);
           //                      ^^^^ Variant "Some" does not exist on enum "MyOtherOption"
           // WRONG: We are type-checking `Option` and `Some` do exist.

    let _: Option<u8> = Option::Some(123u64);
          //            ^^^^^^^^^^^^^^^^^^^^ Mismatched types.
          // expected: u8   // WRONG: Should be `Option<u8>`.
          // found:    u64.   // WRONG: Should be `Option<u64>`.
          // help: Variable declaration's type annotation does not match up with the assigned expression's type.

}

The reason for the first two misleading messages is taking the LHS enum as the type annotation source for the RHS without checking that it is the same enum type.