The conformance role does not expand in the test case.

[liaoyuanng]

Description

@attached(conformance)
public macro demonstration() = #externalMacro(module: "WWDC23Macros", type: "DemostrationMacro")

extension DemostrationMacro: ConformanceMacro {
    public static func expansion<Declaration, Context>(
        of node: AttributeSyntax,
        providingConformancesOf declaration: Declaration,
        in context: Context
    ) throws -> [(TypeSyntax, GenericWhereClauseSyntax?)] where Declaration : DeclGroupSyntax, Context : MacroExpansionContext {
                
        return [("DemonstrationProtocol", nil)]
}


@main
struct WWDCHelperPlugin: CompilerPlugin {
    let providingMacros: [Macro.Type] = [
        DemostrationMacro.self
    ]
}

// in Test file
let testMacros: [String: Macro.Type] = [
    "demonstration": DemostrationMacro.self,
]

func testMacro() {
        assertMacroExpansion(
            """
            @demonstration()
            class TestClass {
            }
            """,
            expandedSource: """
            
            class TestClass {
            }
            extension TestClass : DemonstrationProtocol  {}
            """,
            macros: testMacros
        )
 }

There is an error when I run the test case:

error: -[WWDC23Tests.WWDC23Tests testMacro] : failed - Actual output (+) differed from expected output (-):
 
class TestClass {
 }
–extension TestClass : DemonstrationProtocol  {}

But it runs fine when I execute it in the code.

It seems that the macro is missing the last line when it expands in the test.

Steps to Reproduce

No response

[ahoppen]

Thanks for reporting. This is a duplicate of #1742 and has been fixed by #1742