Only replace async functions with _unsafeInheritExecutor_ versions

Author: DougGregor

lib/Sema/TypeCheckConcurrency.cpp

@@ -2108,7 +2108,8 @@ void swift::introduceUnsafeInheritExecutorReplacements(
 
   auto isReplaceable = [&](ValueDecl *decl) {
     return isa<FuncDecl>(decl) && inConcurrencyModule(decl->getDeclContext()) &&
-        decl->getDeclContext()->isModuleScopeContext();
+        decl->getDeclContext()->isModuleScopeContext() &&
+        cast<FuncDecl>(decl)->hasAsync();
   };
 
   // Make sure at least some of the entries are functions in the _Concurrency
@@ -2163,7 +2164,8 @@ void swift::introduceUnsafeInheritExecutorReplacements(
     return;
 
   auto isReplaceable = [&](ValueDecl *decl) {
-    return isa<FuncDecl>(decl) && inConcurrencyModule(decl->getDeclContext());
+    return isa<FuncDecl>(decl) && inConcurrencyModule(decl->getDeclContext()) &&
+      cast<FuncDecl>(decl)->hasAsync();
   };
 
   // Make sure at least some of the entries are functions in the _Concurrency

test/Concurrency/unsafe_inherit_executor.swift

@@ -117,7 +117,12 @@ func unsafeCallerAvoidsNewLoop(clock: some Clock) async throws {
   } onCancel: {
   }
 
-  await TL.$string.withValue("hello") {
+  TL.$string.withValue("hello") {
+    print(TL.string)
+  }
+
+  try await TL.$string.withValue("hello") {
+    try await Task.sleep(nanoseconds: 500)
     print(TL.string)
   }