diff --git a/lib/ASTGen/Sources/ASTGen/Macros.swift b/lib/ASTGen/Sources/ASTGen/Macros.swift
index 4f43906b4fd7f..919dd9f9941a6 100644
--- a/lib/ASTGen/Sources/ASTGen/Macros.swift
+++ b/lib/ASTGen/Sources/ASTGen/Macros.swift
@@ -508,7 +508,8 @@ func expandFreestandingMacroIPC(
     macro: .init(moduleName: macro.moduleName, typeName: macro.typeName, name: macroName),
     macroRole: pluginMacroRole,
     discriminator: discriminator,
-    syntax: PluginMessage.Syntax(syntax: Syntax(expansionSyntax), in: sourceFilePtr)!
+    syntax: PluginMessage.Syntax(syntax: Syntax(expansionSyntax), in: sourceFilePtr)!,
+    lexicalContext: pluginLexicalContext(of: expansionSyntax)
   )
   do {
     let result = try macro.plugin.sendMessageAndWait(message)
@@ -564,6 +565,7 @@ func expandFreestandingMacroInProcess(
   sourceManager.insert(sourceFilePtr)
 
   let context = sourceManager.createMacroExpansionContext(
+    lexicalContext: lexicalContext(of: expansionSyntax),
     discriminator: discriminator
   )
 
@@ -757,6 +759,20 @@ func expandAttachedMacro(
   )
 }
 
+/// Produce the full lexical context of the given node to pass along to
+/// macro expansion.
+private func lexicalContext(of node: some SyntaxProtocol) -> [Syntax] {
+  // FIXME: Should we query the source manager to get the macro expansion
+  // information?
+  node.allMacroLexicalContexts()
+}
+
+/// Produce the full lexical context of the given node to pass along to
+/// macro expansion.
+private func pluginLexicalContext(of node: some SyntaxProtocol) -> [PluginMessage.Syntax] {
+  lexicalContext(of: node).compactMap { .init(syntax: $0) }
+}
+
 func expandAttachedMacroIPC(
   diagEnginePtr: UnsafeMutableRawPointer,
   macroPtr: UnsafeRawPointer,
@@ -829,6 +845,7 @@ func expandAttachedMacroIPC(
     conformanceListSyntax = .init(syntax: Syntax(placeholderDecl))!
   }
 
+
   // Send the message.
   let message = HostToPluginMessage.expandAttachedMacro(
     macro: .init(moduleName: macro.moduleName, typeName: macro.typeName, name: macroName),
@@ -838,7 +855,8 @@ func expandAttachedMacroIPC(
     declSyntax: declSyntax,
     parentDeclSyntax: parentDeclSyntax,
     extendedTypeSyntax: extendedTypeSyntax,
-    conformanceListSyntax: conformanceListSyntax
+    conformanceListSyntax: conformanceListSyntax,
+    lexicalContext: pluginLexicalContext(of: declarationNode)
   )
   do {
     let expandedSource: String?
@@ -926,6 +944,7 @@ func expandAttachedMacroInProcess(
 
   // Create an expansion context
   let context = sourceManager.createMacroExpansionContext(
+    lexicalContext: lexicalContext(of: declarationNode),
     discriminator: discriminator
   )
 
diff --git a/lib/ASTGen/Sources/ASTGen/SourceManager+MacroExpansionContext.swift b/lib/ASTGen/Sources/ASTGen/SourceManager+MacroExpansionContext.swift
index ae6d7635642a2..0587241817f5c 100644
--- a/lib/ASTGen/Sources/ASTGen/SourceManager+MacroExpansionContext.swift
+++ b/lib/ASTGen/Sources/ASTGen/SourceManager+MacroExpansionContext.swift
@@ -19,6 +19,9 @@ extension SourceManager {
     /// The source manager.
     private let sourceManager: SourceManager
 
+    /// The lexical context for this expansion.
+    let lexicalContext: [Syntax]
+
     /// The set of diagnostics that were emitted as part of expanding the
     /// macro.
     var diagnostics: [Diagnostic] = []
@@ -35,18 +38,25 @@ extension SourceManager {
     /// Used in conjunction with `expansionDiscriminator`.
     private var uniqueNames: [String: Int] = [:]
 
-    init(sourceManager: SourceManager, discriminator: String) {
+    init(
+      sourceManager: SourceManager,
+      lexicalContext: [Syntax],
+      discriminator: String
+    ) {
       self.sourceManager = sourceManager
+      self.lexicalContext = lexicalContext
       self.discriminator = discriminator
     }
   }
 
   /// Create a new macro expansion context
   func createMacroExpansionContext(
+    lexicalContext: [Syntax],
     discriminator: String = ""
   ) -> MacroExpansionContext {
     return MacroExpansionContext(
       sourceManager: self,
+      lexicalContext: lexicalContext,
       discriminator: discriminator
     )
   }
diff --git a/test/Macros/Inputs/syntax_macro_definitions.swift b/test/Macros/Inputs/syntax_macro_definitions.swift
index 3f5a75939fd56..fb7bd5f71c3a9 100644
--- a/test/Macros/Inputs/syntax_macro_definitions.swift
+++ b/test/Macros/Inputs/syntax_macro_definitions.swift
@@ -2316,3 +2316,13 @@ public struct AddSubscript: MemberMacro {
     ]
   }
 }
+
+public struct AllLexicalContextsMacro: DeclarationMacro {
+  public static func expansion(
+    of node: some FreestandingMacroExpansionSyntax,
+    in context: some MacroExpansionContext
+  ) throws -> [DeclSyntax] {
+    context.lexicalContext.compactMap { $0.as(DeclSyntax.self)?.trimmed }
+  }
+}
+
diff --git a/test/Macros/macro_plugin_basic.swift b/test/Macros/macro_plugin_basic.swift
index 153375e16d831..3208b0e73fed9 100644
--- a/test/Macros/macro_plugin_basic.swift
+++ b/test/Macros/macro_plugin_basic.swift
@@ -30,9 +30,9 @@
 
 // CHECK: ->(plugin:[[#PID:]]) {"getCapability":{"capability":{"protocolVersion":[[#PROTOCOL_VERSION:]]}}}
 // CHECK: <-(plugin:[[#PID]]) {"getCapabilityResult":{"capability":{"protocolVersion":1}}}
-// CHECK: ->(plugin:[[#PID]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","macro":{"moduleName":"TestPlugin","name":"testString","typeName":"TestStringMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":5,"offset":301},"source":"#testString(123)"}}}
+// CHECK: ->(plugin:[[#PID]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}func test{{.*}}],"macro":{"moduleName":"TestPlugin","name":"testString","typeName":"TestStringMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":5,"offset":301},"source":"#testString(123)"}}}
 // CHECK: <-(plugin:[[#PID]]) {"expandFreestandingMacroResult":{"diagnostics":[],"expandedSource":"\"123\"\n  +   \"foo  \""}}
-// CHECK: ->(plugin:[[#PID]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","macro":{"moduleName":"TestPlugin","name":"testStringWithError","typeName":"TestStringWithErrorMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":6,"offset":336},"source":"#testStringWithError(321)"}}}
+// CHECK: ->(plugin:[[#PID]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"TestPlugin","name":"testStringWithError","typeName":"TestStringWithErrorMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":6,"offset":336},"source":"#testStringWithError(321)"}}}
 // CHECK: <-(plugin:[[#PID]]) {"expandFreestandingMacroResult":{"diagnostics":[{"fixIts":[],"highlights":[],"message":"message from plugin","notes":[],"position":{"fileName":"{{.*}}test.swift","offset":336},"severity":"error"}],"expandedSource":"\"bar\""}}
 
 //--- test.swift
diff --git a/test/Macros/macro_plugin_error.swift b/test/Macros/macro_plugin_error.swift
index 62b8114bd4afa..f57d8272ccd55 100644
--- a/test/Macros/macro_plugin_error.swift
+++ b/test/Macros/macro_plugin_error.swift
@@ -17,14 +17,14 @@
 
 // CHECK: ->(plugin:[[#PID1:]]) {"getCapability":{"capability":{"protocolVersion":[[#PROTOCOL_VERSION:]]}}}
 // CHECK-NEXT: <-(plugin:[[#PID1]]) {"getCapabilityResult":{"capability":{"protocolVersion":1}}}
-// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","macro":{"moduleName":"TestPlugin","name":"fooMacro","typeName":"FooMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":7,"offset":[[#]]},"source":"#fooMacro(1)"}}}
+// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"TestPlugin","name":"fooMacro","typeName":"FooMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":7,"offset":[[#]]},"source":"#fooMacro(1)"}}}
 // CHECK-NEXT: <-(plugin:[[#PID1]]) {"invalidResponse":{}}
-// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","macro":{"moduleName":"TestPlugin","name":"fooMacro","typeName":"FooMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":9,"offset":[[#]]},"source":"#fooMacro(2)"}}}
+// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"TestPlugin","name":"fooMacro","typeName":"FooMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":9,"offset":[[#]]},"source":"#fooMacro(2)"}}}
 // ^ This messages causes the mock plugin exit because there's no matching expected message.
 
 // CHECK: ->(plugin:[[#PID2:]]) {"getCapability":{"capability":{"protocolVersion":[[#PROTOCOL_VERSION]]}}}
 // CHECK-NEXT: <-(plugin:[[#PID2]]) {"getCapabilityResult":{"capability":{"protocolVersion":1}}}
-// CHECK-NEXT: ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","macro":{"moduleName":"TestPlugin","name":"fooMacro","typeName":"FooMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":11,"offset":[[#]]},"source":"#fooMacro(3)"}}}
+// CHECK-NEXT: ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"$s{{.+}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"TestPlugin","name":"fooMacro","typeName":"FooMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{"column":19,"fileID":"MyApp/test.swift","fileName":"{{.+}}test.swift","line":11,"offset":[[#]]},"source":"#fooMacro(3)"}}}
 // CHECK-NEXT: <-(plugin:[[#PID2:]]) {"expandFreestandingMacroResult":{"diagnostics":[],"expandedSource":"3.description"}}
 
 //--- test.swift
diff --git a/test/Macros/macro_plugin_server.swift b/test/Macros/macro_plugin_server.swift
index d8b8db9c058ba..85c641f0e20b3 100644
--- a/test/Macros/macro_plugin_server.swift
+++ b/test/Macros/macro_plugin_server.swift
@@ -50,9 +50,9 @@
 // CHECK-NEXT: <-(plugin:[[#PID1]]) {"loadPluginLibraryResult":{"diagnostics":[],"loaded":true}}
 // CHECK-NEXT: ->(plugin:[[#PID1]]) {"loadPluginLibrary":{"libraryPath":"{{.*}}EvilMacros.{{dylib|so|dll}}","moduleName":"EvilMacros"}}
 // CHECK-NEXT: <-(plugin:[[#PID1]]) {"loadPluginLibraryResult":{"diagnostics":[],"loaded":true}}
-// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","macro":{"moduleName":"MacroDefinition","name":"stringify","typeName":"StringifyMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{.+}}},"source":"#stringify(a + b)"}}}
+// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"MacroDefinition","name":"stringify","typeName":"StringifyMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{.+}}},"source":"#stringify(a + b)"}}}
 // CHECK-NEXT: <-(plugin:[[#PID1]]) {"expandMacroResult":{"diagnostics":[],"expandedSource":"(a + b, \"a + b\")"}}
-// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","macro":{"moduleName":"EvilMacros","name":"evil","typeName":"CrashingMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{.+}}},"source":"#evil(42)"}}}
+// CHECK-NEXT: ->(plugin:[[#PID1]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"EvilMacros","name":"evil","typeName":"CrashingMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{.+}}},"source":"#evil(42)"}}}
 // ^ This crashes the plugin server.
 
 // CHECK: ->(plugin:[[#PID2:]]) {"getCapability":{"capability":{"protocolVersion":[[#PROTOCOL_VERSION]]}}}
@@ -61,12 +61,12 @@
 // CHECK-NEXT: <-(plugin:[[#PID2]]) {"loadPluginLibraryResult":{"diagnostics":[],"loaded":true}}
 // CHECK-NEXT: ->(plugin:[[#PID2]]) {"loadPluginLibrary":{"libraryPath":"{{.*}}EvilMacros.{{dylib|so|dll}}","moduleName":"EvilMacros"}}
 // CHECK-NEXT: <-(plugin:[[#PID2]]) {"loadPluginLibraryResult":{"diagnostics":[],"loaded":true}}
-// CHECK-NEXT: ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","macro":{"moduleName":"MacroDefinition","name":"stringify","typeName":"StringifyMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{.+}}},"source":"#stringify(b + a)"}}}
+// CHECK-NEXT: ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"MacroDefinition","name":"stringify","typeName":"StringifyMacro"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{.+}}},"source":"#stringify(b + a)"}}}
 // CHECK-NEXT: <-(plugin:[[#PID2]]) {"expandMacroResult":{"diagnostics":[],"expandedSource":"(b + a, \"b + a\")"}}
 
-// CHECK-NEXT ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","macro":{"moduleName":"MacroDefinition","name":"missing","typeName":"TypeDoesNotExist"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{*}}},"source":" #missing()"}}}
+// CHECK-NEXT ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"MacroDefinition","name":"missing","typeName":"TypeDoesNotExist"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{*}}},"source":" #missing()"}}}
 // CHECK-NEXT <-(plugin:[[#PID2]]) {"expandMacroResult":{"diagnostics":[{"fixIts":[],"highlights":[{{{.*}}}],"message":"macro implementation type 'MacroDefinition.TypeDoesNotExist' could not be found in library plugin '{{.*}}MacroDefinition.{{dylib|so|dll}}'","notes":[],"position":{{{.*}}},"severity":"error"}]}}
-// CHECK-NEXT ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","macro":{"moduleName":"MacroDefinition","name":"missing","typeName":"TypeDoesNotExist"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{*}}},"source":" #notMacro()"}}}
+// CHECK-NEXT ->(plugin:[[#PID2]]) {"expandFreestandingMacro":{"discriminator":"${{.*}}","lexicalContext":[{{.*}}],"macro":{"moduleName":"MacroDefinition","name":"missing","typeName":"TypeDoesNotExist"},"macroRole":"expression","syntax":{"kind":"expression","location":{{{*}}},"source":" #notMacro()"}}}
 // CHECK-NEXT <-(plugin:[[#PID2]]) {"expandMacroResult":{"diagnostics":[{"fixIts":[],"highlights":[{{{.*}}}],"message":"type 'MacroDefinition.NotMacroStruct' is not a valid macro implementation type in library plugin '{{.*}}MacroDefinition.{{dylib|so|dll}}'","notes":[],"position":{{{.*}}},"severity":"error"}]}}
 
 @freestanding(expression) macro stringify<T>(_ value: T) -> (T, String) = #externalMacro(module: "MacroDefinition", type: "StringifyMacro")