Merge pull request swiftlang#23420 from aschwaighofer/defer_body_not_dynamic

Sema: Don't add dynamic to defer bodies

Author: aschwaighofer

lib/Sema/TypeCheckAttr.cpp

@@ -2566,6 +2566,12 @@ void TypeChecker::addImplicitDynamicAttribute(Decl *D) {
       D->getAttrs().hasAttribute<InlinableAttr>())
     return;
 
+  if (auto *FD = dyn_cast<FuncDecl>(D)) {
+    // Don't add dynamic to defer bodies.
+    if (FD->isDeferBody())
+      return;
+  }
+
   if (auto *VD = dyn_cast<VarDecl>(D)) {
     // Don't turn stored into computed properties. This could conflict with
     // exclusivity checking.

test/SILGen/dynamically_replaceable.swift

@@ -356,3 +356,9 @@ func getsetX(_ x: Int) -> Int {
 dynamic func funcWithDefaultArg(_ arg : String = String("hello")) {
   print("hello")
 }
+
+// IMPLICIT-LABEL: sil private [ossa] @$s23dynamically_replaceable6$deferL_yyF
+var x = 10
+defer {
+  let y = x
+}