I have an extension macro which adds Codable conformance (and other protocols, though they don't matter). The macro expands the code:
@Foo
public struct Name {
private var value: String
}
to:
public struct Name {
private var value: String
}
extension Name: Codable {
}
The expanded code compiles, but the original code doesn't. The error:
'_value' is inaccessible due to 'private' protection level
If I add an internal (or pubic) init(), the error is gone. I wonder if anyone observed the issue? Is it a bug?
I ran into the issue in my app code where I use Foo macro, MemberInit macro, and property wrapper together, like the following:
@Foo
@MemberInit
public struct Name {
@SomePW var value: String
}
From what I read, during macro expansion Foo can't see the public init() generated by MemberInit. I suspect that somehow caused the issue, though I don't understand why, because from my understanding Codable doesn't depends on init() provided by other code. The fact that transformed code compiles also proves it.
Foo macro code (simplified version):
public enum FooMacro: ExtensionMacro {
public static func expansion(
of node: AttributeSyntax,
attachedTo declaration: some DeclGroupSyntax,
providingExtensionsOf type: some TypeSyntaxProtocol,
conformingTo protocols: [TypeSyntax],
in context: some MacroExpansionContext
) throws -> [ExtensionDeclSyntax] {
let extensionDecl = try ExtensionDeclSyntax(
"""
extension \(type.trimmed): Codables {
}
"""
)
return [extensionDecl]
}
}
(BTW, I’m not sure if it’s just me, but this is not the first time I run into weird issues like this - expanded code compiles but original code doesn’t. Fortunately this time I am able to narrow it down).
UPDATE: I submitted bug #70086