Parser: crashing invalid constructs

This is a list of language construct that cause the compiler to fail. This can be crashes or just asserts() because of a feature is not yet implemented.

MemberExpr analysis

a.getB().getC().cStructFunc()

should work, but gives invalid error. Need better analysis of MemberExpr

Substruct/union initialization

type Value struct {
   u32 id;
   union {
       i32 number;
       const char* text;
   }
}
Value v1 = { .number = 10 }  // should work
Value v2 = { 10, .num = 10 } // should work
Value v3 = { 20, .text = "hello" } // should work

• allow initializing any (one) member of a union
• c currently allows this as well.
• TBD: when not to allow mixing designated init operators and undesignated ones?