[Macros] Rename ExpressionMacro.apply to "expand".

"Expand" better describes what the macro implementation is doing.

Author: DougGregor

Sources/_SwiftSyntaxMacros/ExpressionMacro.swift

@@ -19,10 +19,10 @@ import _CompilerPluginSupport
 
 /// Describes a macro that is explicitly expanded as an expression.
 public protocol ExpressionMacro: Macro {
-  /// Expansion a macro described by the given macro expansion expression
+  /// Expand a macro described by the given macro expansion expression
   /// within the given context to produce a replacement expression.
-  static func apply(
-    _ expansion: MacroExpansionExprSyntax,
+  static func expand(
+    _ node: MacroExpansionExprSyntax,
     in context: inout MacroExpansionContext
   ) -> ExprSyntax
 }
@@ -78,7 +78,7 @@ extension ExpressionMacro {
     }
 
     // Evaluate the macro.
-    let evalResult = apply(mee, in: context)
+    let evalResult = expand(mee, in: context)
 
     let rawDiags = UnsafeMutablePointer<_Diagnostic>.allocate(
       capacity: evalResult.diagnostics.count)

Sources/_SwiftSyntaxMacros/MacroSystem+Builtin.swift

@@ -27,7 +27,7 @@ private func replaceFirstLabel(
 }
 
 public struct ColorLiteralMacro: ExpressionMacro {
-  public static func apply(
+  public static func expand(
     _ macro: MacroExpansionExprSyntax, in context: inout MacroExpansionContext
   ) -> ExprSyntax {
     let argList = replaceFirstLabel(
@@ -42,7 +42,7 @@ public struct ColorLiteralMacro: ExpressionMacro {
 }
 
 public struct FileLiteralMacro: ExpressionMacro {
-  public static func apply(
+  public static func expand(
     _ macro: MacroExpansionExprSyntax, in context: inout MacroExpansionContext
   ) -> ExprSyntax {
     let argList = replaceFirstLabel(
@@ -57,7 +57,7 @@ public struct FileLiteralMacro: ExpressionMacro {
 }
 
 public struct ImageLiteralMacro: ExpressionMacro {
-  public static func apply(
+  public static func expand(
     _ macro: MacroExpansionExprSyntax, in context: inout MacroExpansionContext
   ) -> ExprSyntax {
     let argList = replaceFirstLabel(
@@ -72,7 +72,7 @@ public struct ImageLiteralMacro: ExpressionMacro {
 }
 
 public struct FileIDMacro: ExpressionMacro {
-  public static func apply(
+  public static func expand(
     _ macro: MacroExpansionExprSyntax, in context: inout MacroExpansionContext
   ) -> ExprSyntax {
     // FIXME: Compiler has more sophisticated file ID computation

Sources/_SwiftSyntaxMacros/MacroSystem+Examples.swift

@@ -15,7 +15,7 @@ import SwiftSyntaxBuilder
 
 // Macros used for testing purposes
 public struct StringifyMacro: ExpressionMacro {
-  public static func apply(
+  public static func expand(
     _ macro: MacroExpansionExprSyntax, in context: inout MacroExpansionContext
   ) -> ExprSyntax {
     guard let argument = macro.argumentList.first?.expression else {

Sources/_SwiftSyntaxMacros/Syntax+MacroEvaluation.swift

@@ -41,7 +41,7 @@ extension MacroExpansionExprSyntax {
     }
 
     // Handle the rewrite.
-    return exprMacro.apply(disconnectedCopy(), in: &context)
+    return exprMacro.expand(disconnectedCopy(), in: &context)
   }
 }
 

Tests/SwiftSyntaxMacrosTest/MacroSystemTests.swift

@@ -19,7 +19,7 @@ import _SwiftSyntaxTestSupport
 /// Macro whose only purpose is to ensure that we cannot see "out" of the
 /// macro expansion syntax node we were given.
 struct CheckContextIndependenceMacro: ExpressionMacro {
-  static func apply(
+  static func expand(
     _ macro: MacroExpansionExprSyntax,
     in context: inout MacroExpansionContext) -> ExprSyntax {