Diagnose CustomAttrs as needed in @abi (macro tests)

Additional tests for the previous commit “Diagnose CustomAttrs as needed in `@abi`”.

Author: beccadax

test/Macros/macro_expand_peers.swift

@@ -1,17 +1,18 @@
 // REQUIRES: swift_swift_parser, executable_test
+// REQUIRES: swift_feature_ABIAttribute
 
 // For _Concurrency.
 // UNSUPPORTED: use_os_stdlib
 // UNSUPPORTED: back_deployment_runtime
 
 // RUN: %empty-directory(%t)
 // RUN: %host-build-swift -swift-version 5 -emit-library -o %t/%target-library-name(MacroDefinition) -parse-as-library -module-name=MacroDefinition %S/Inputs/syntax_macro_definitions.swift -g -no-toolchain-stdlib-rpath
-// RUN: %target-typecheck-verify-swift -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -parse-as-library -disable-availability-checking -DTEST_DIAGNOSTICS
+// RUN: %target-typecheck-verify-swift -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -parse-as-library -disable-availability-checking -enable-experimental-feature ABIAttribute -DTEST_DIAGNOSTICS
 
 // Check with the imported macro library vs. the local declaration of the macro.
 // RUN: %target-swift-frontend -swift-version 5 -emit-module -o %t/macro_library.swiftmodule %S/Inputs/macro_library.swift -module-name macro_library -load-plugin-library %t/%target-library-name(MacroDefinition)
 
-// RUN: %target-typecheck-verify-swift -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -parse-as-library -disable-availability-checking -DIMPORT_MACRO_LIBRARY -I %t -DTEST_DIAGNOSTICS
+// RUN: %target-typecheck-verify-swift -swift-version 5 -load-plugin-library %t/%target-library-name(MacroDefinition) -parse-as-library -disable-availability-checking -DIMPORT_MACRO_LIBRARY -I %t -enable-experimental-feature ABIAttribute -DTEST_DIAGNOSTICS
 
 
 // RUN: %target-swift-frontend -swift-version 5 -typecheck -load-plugin-library %t/%target-library-name(MacroDefinition) -parse-as-library %s -disable-availability-checking -dump-macro-expansions > %t/expansions-dump.txt 2>&1
@@ -309,3 +310,26 @@ func closuresInPeerMacroCrash() {}
 @trait(Trait {})
 @trait(Trait {})
 var closuresInPeerMacroOnVariableCrash: Int = 0
+
+// Test that macros can't be used in @abi
+
+#if swift(>=5.3) && TEST_DIAGNOSTICS
+struct ABIAttrWithAttachedMacro {
+  // expected-error@+1 {{macro 'addCompletionHandler()' cannot be expanded in '@abi' attribute}}
+  @abi(@addCompletionHandler func fn1() async)
+  @addCompletionHandler func fn1() async {}
+  // From diagnostics in the expansion:
+  // expected-note@-2 3{{in expansion of macro 'addCompletionHandler' on instance method 'fn1()' here}}
+  // expected-note@-4 {{'fn1()' previously declared here}}
+
+  // expected-error@+1 {{macro 'addCompletionHandler()' cannot be expanded in '@abi' attribute}}
+  @abi(@addCompletionHandler func fn2() async)
+  func fn2() async {}
+
+  @abi(func fn3() async)
+  @addCompletionHandler func fn3() async {}
+  // From diagnostics in the expansion:
+  // expected-note@-2 2{{in expansion of macro 'addCompletionHandler' on instance method 'fn3()' here}}
+  // expected-note@-4 {{'fn3()' previously declared here}}
+}
+#endif