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Ah, right, I missed this: https://go.googlesource.com/proposal/+/refs/heads/master/design/go2draft-type-parameters.md#methods-may-not-take-additional-type-argu

by lsllc 6y ago

Ah, right, I missed this: https://go.googlesource.com/proposal/+/refs/heads/master/design/go2draft-type-parameters.md#methods-may-not-take-additional-type-arguments https://go.googlesource.com/proposal/+/refs/heads/master/des... Hmmm ... not sure how I feel about that. Ok so my original example becomes this: func (obj *SomeType) Foo(type K, V, Q comparable)(key K, val V) (*OtherType(Q, V), error) { ... } Which is only slightly better [without the generic type]. Don't get me wrong, I'm a big fan of Go, but I'm kind of on the fence about generic types. I've made do with casting interfaces and type-casts for many years and I'm OK with it (honestly, glad to not be a C++ or Java programmer anymore).

mseepgood 6y ago
> Ok so my original example becomes this No, you still don't understand. Methods can't have additional type parameters, only functions. This part is not allowed in your "example": (type K, V, Q comparable)
- lsllc 6y ago
  The doc says: > Generic types can have methods. The receiver type of a method must declare the same number of type parameters as are declared in the receiver type's definition. They are declared without the type keyword or any constraint. So my original example should have been: func (obj *SomeType(K, V)) Foo(key K, val V) (*OtherType(K, V), error) { ... } (hopefully this is now correct!).