Merge pull request swiftlang#1469 from DougGregor/macro-context-add-diags

Author: DougGregor

Sources/SwiftCompilerPluginMessageHandling/Macros.swift

@@ -69,14 +69,8 @@ extension CompilerPluginMessageHandler {
  throw MacroExpansionError.unmathedMacroRole
  }
  } catch {
- let diagMessage: DiagnosticMessage
- if let message = error as? DiagnosticMessage, message.severity == .error {
- diagMessage = message
- } else {
- diagMessage = ThrownErrorDiagnostic(message: String(describing: error))
- }
+ context.addDiagnostics(from: error, node: syntax)
  expandedSource = ""
- context.diagnose(Diagnostic(node: syntax, message: diagMessage))
  }
 
  let diagnostics = context.diagnostics.map {
@@ -228,14 +222,8 @@ extension CompilerPluginMessageHandler {
  throw MacroExpansionError.unmathedMacroRole
  }
  } catch {
- let diagMessage: DiagnosticMessage
- if let message = error as? DiagnosticMessage, message.severity == .error {
- diagMessage = message
- } else {
- diagMessage = ThrownErrorDiagnostic(message: String(describing: error))
- }
+ context.addDiagnostics(from: error, node: attributeNode)
  expandedSources = []
- context.diagnose(Diagnostic(node: Syntax(attributeNode), message: diagMessage))
  }
 
  let diagnostics = context.diagnostics.map {
@@ -246,14 +234,3 @@ extension CompilerPluginMessageHandler {
  )
  }
 }
-
-/// Diagnostic message used for thrown errors.
-fileprivate struct ThrownErrorDiagnostic: DiagnosticMessage {
- let message: String
-
- var severity: DiagnosticSeverity { .error }
-
- var diagnosticID: MessageID {
- .init(domain: "SwiftSyntaxMacros", id: "ThrownErrorDiagnostic")
- }
-}

Sources/SwiftSyntaxMacros/MacroExpansionContext.swift

@@ -189,22 +189,23 @@ private struct ThrownErrorDiagnostic: DiagnosticMessage {
 extension MacroExpansionContext {
  /// Add diagnostics from the error thrown during macro expansion.
  public func addDiagnostics<S: SyntaxProtocol>(from error: Error, node: S) {
- guard let diagnosticsError = error as? DiagnosticsError else {
-  diagnose(
-  Diagnostic(
-  node: Syntax(node),
-  message: ThrownErrorDiagnostic(message: String(describing: error))
-  )
-  )
- return
+ // Inspect the error to form an appropriate set of diagnostics.
+ var diagnostics: [Diagnostic]
+ if let diagnosticsError = error as? DiagnosticsError {
+ diagnostics = diagnosticsError.diagnostics
+ } else if let message = error as? DiagnosticMessage {
+ diagnostics = [Diagnostic(node: Syntax(node), message: message)]
+ } else {
+ diagnostics = [Diagnostic(node: Syntax(node), message: ThrownErrorDiagnostic(message: String(describing: error)))]
  }
 
- for diagnostic in diagnosticsError.diagnostics {
+ // Emit the diagnostics.
+ for diagnostic in diagnostics {
  diagnose(diagnostic)
  }
 
- // handle possibility that none of the diagnostics was an error
- if !diagnosticsError.diagnostics.contains(
+ // Handle possibility that none of the diagnostics was an error.
+ if !diagnostics.contains(
  where: { $0.diagMessage.severity == .error }
  ) {
  diagnose(

Sources/SwiftSyntaxMacros/MacroReplacement.swift

@@ -14,7 +14,7 @@ enum MacroExpanderError: DiagnosticMessage {
  return "macro expansion requires a definition"
 
  case .definitionNotMacroExpansion:
- return "macro definition must itself by a macro expansion expression (starting with '#')"
+ return "macro must itself be defined by a macro expansion expression (starting with '#')"
 
  case .nonParameterReference(let name):
  return "reference to value '\(name.text)' that is not a macro parameter in expansion"