Store the interpreter value of the interface object to wrap as
a field called IValue, at offset 0 in wrapper structures.
Update extract to include IValue field.
In typeAssert, detect interface wrapper, and dereference the
interpreter value from IValue wrapper field.
Fixes#1166.
The heuristic to generate a package name identifier was incorrect. Now for binary packages, the package identifier is obtained by a symbol, generated by extract, which contains the string argument of package statement in source file. This should ensure an always correct default package identifier.
Fixes#1095.
This adds type checking to CallExpr (excluding builtin type checking, as that is a PR in its own right) as well as handling any required constant type conversion.
This also changes constant strings and runes to be represented as `constant.Value`. Runes change `rval` type at CFG typing time to avoid having to type at AST time. There are also changes to importSpecs and `stdlib` to account for the string change. With this all `untyped` types should now be `constant.Value`s, although errors are still not returned if this is not the case to be sure we do not break things.
This also fixed a bug in `itype.methods` that would panic if the type was recursive.
