Properly deprecate default implementation of MacroExpansionContext.lexicalContext

ahoppen · ahoppen · commit 1c87ea5993f0 · 2024-06-23T07:36:16.000-07:00
Now that we have, we can change the default implementation of `MacroExpansionContext.lexicalContext` to return an empty array and be deprecated, making not implementing `lexicalContext` a compile-time warning instead of a runtime error.

rdar://123410459
diff --git a/Sources/SwiftSyntaxMacros/MacroExpansionContext.swift b/Sources/SwiftSyntaxMacros/MacroExpansionContext.swift
@@ -88,11 +88,18 @@ extension MacroExpansionContext {
     return location(of: node, at: .afterLeadingTrivia, filePathMode: .fileID)
   }
 
+  #if compiler(>=6.0)
+  @available(*, deprecated, message: "`MacroExpansionContext` conformance must implement `lexicalContext`")
+  public var lexicalContext: [Syntax] {
+    return []
+  }
+  #else
   public var lexicalContext: [Syntax] {
     fatalError(
       "`MacroExpansionContext` conformance must implement `lexicalContext`"
     )
   }
+  #endif
 }
 
 /// Diagnostic message used for thrown errors.

Original file line number	Diff line number	Diff line change
`@@ -88,11 +88,18 @@ extension MacroExpansionContext {`
`88`	`88`	`return location(of: node, at: .afterLeadingTrivia, filePathMode: .fileID)`
`89`	`89`	`}`
`90`	`90`
	`91`	`+ #if compiler(>=6.0)`
	`92`	+ @available(*, deprecated, message: "`MacroExpansionContext` conformance must implement `lexicalContext`")
	`93`	`+ public var lexicalContext: [Syntax] {`
	`94`	`+ return []`
	`95`	`+ }`
	`96`	`+ #else`
`91`	`97`	`public var lexicalContext: [Syntax] {`
`92`	`98`	`fatalError(`
`93`	`99`	"`MacroExpansionContext` conformance must implement `lexicalContext`"
`94`	`100`	`)`
`95`	`101`	`}`
	`102`	`+ #endif`
`96`	`103`	`}`
`97`	`104`
`98`	`105`	`/// Diagnostic message used for thrown errors.`