[Macros] Pass macro role for freestanding macro expansion #1757
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Macros can only have a single freestanding macro role, so that their expansion is unambiguous. However, that restriction is at the level of a macro declaration, and is not reflected in a similar restriction on the set of macro protocols to which a macro implementation can conform. Therefore, have the compiler pass a freestanding macro role through to macro expansion in the same way that we do for attached macros, and use that to determine which macro protocol to use. Part of fixing rdar://110418969.
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@swift-ci please test |
| switch pluginMacroRole { | ||
| case .expression: macroRole = .expression | ||
| case .declaration: macroRole = .declaration | ||
| case .codeItem: macroRole = .codeItem | ||
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| case .accessor, .conformance, .member, .memberAttribute, .peer: | ||
| throw MacroExpansionError.invalidMacroRole(pluginMacroRole) | ||
| } |
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(Not critical at all)
Could you use MacroRole.init(messageMacroRole: PluginMessage.MacroRole) (at the bottom of this file) here?
Since expandFreestandingMacro diagnoses unmatched macro role, and invalid macro role here would be a compiler error, diagnosing invalid is not necessary I think.
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But if we do diagnose invalid role here, we should do it in expandAttachedMacro() too
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I'd rather be defensive here, because we're on one side of an IPC barrier
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Nevermind, I see what you mean. It'll be checked and produce an error down in expandFreestandingMacro, so we don't need the redundant check here.
Macros can only have a single freestanding macro role, so that their
expansion is unambiguous. However, that restriction is at the level of a
macro declaration, and is not reflected in a similar restriction on the
set of macro protocols to which a macro implementation can conform.
Therefore, have the compiler pass a freestanding macro role through to
macro expansion in the same way that we do for attached macros, and
use that to determine which macro protocol to use.
Part of fixing rdar://110418969.