From 4089775de8e948fec3d87c884a86ae72f3208043 Mon Sep 17 00:00:00 2001
From: Meghana Gupta <meghana_gupta@apple.com>
Date: Wed, 19 Nov 2025 06:29:57 +0530
Subject: [PATCH] Fix swiftinterface printing of accessors and inferred
 lifetime dependencies when Lifetimes feature is enabled

---
 lib/AST/FeatureSet.cpp                        | 46 ++++++++++++++-----
 .../lifetime_underscored_dependence.swift     | 12 +++++
 ...lifetime_underscored_dependence_test.swift | 21 +++++++--
 3 files changed, 64 insertions(+), 15 deletions(-)

diff --git a/lib/AST/FeatureSet.cpp b/lib/AST/FeatureSet.cpp
index 27ce1e26921d2..4e6de42c78db1 100644
--- a/lib/AST/FeatureSet.cpp
+++ b/lib/AST/FeatureSet.cpp
@@ -150,36 +150,42 @@ UNINTERESTING_FEATURE(CheckImplementationOnly)
 UNINTERESTING_FEATURE(CheckImplementationOnlyStrict)
 UNINTERESTING_FEATURE(EnforceSPIOperatorGroup)
 
-static bool findUnderscoredLifetimeAttr(Decl *decl) {
-  auto hasUnderscoredLifetimeAttr = [](Decl *decl) {
+static bool findLifetimeAttr(Decl *decl, bool findUnderscored) {
+  auto hasLifetimeAttr = [&](Decl *decl) {
     if (!decl->getAttrs().hasAttribute<LifetimeAttr>()) {
       return false;
     }
     // Since we ban mixing @lifetime and @_lifetime on the same decl, checking
     // any one LifetimeAttr on the decl is sufficient.
     // FIXME: Implement the ban.
-    return decl->getAttrs().getAttribute<LifetimeAttr>()->isUnderscored();
+    if (findUnderscored) {
+      return decl->getAttrs().getAttribute<LifetimeAttr>()->isUnderscored();
+    }
+    return !decl->getAttrs().getAttribute<LifetimeAttr>()->isUnderscored();
   };
 
   switch (decl->getKind()) {
   case DeclKind::Var: {
     auto *var = cast<VarDecl>(decl);
-    return llvm::any_of(var->getAllAccessors(), hasUnderscoredLifetimeAttr);
+    return llvm::any_of(var->getAllAccessors(), hasLifetimeAttr);
   }
   default:
-    return hasUnderscoredLifetimeAttr(decl);
+    return hasLifetimeAttr(decl);
   }
 }
 
 static bool usesFeatureLifetimeDependence(Decl *decl) {
-  if (decl->getAttrs().hasAttribute<LifetimeAttr>()) {
-    if (findUnderscoredLifetimeAttr(decl)) {
-      // Experimental feature Lifetimes will guard the decl.
-      return false;
-    }
+  if (findLifetimeAttr(decl, /*findUnderscored*/ false)) {
     return true;
   }
 
+  // Guard inferred lifetime dependencies with LifetimeDependence if it was
+  // enabled.
+  if (!decl->getASTContext().LangOpts.hasFeature(Feature::LifetimeDependence)) {
+    return false;
+  }
+
+  // Check for inferred lifetime dependencies
   if (auto *afd = dyn_cast<AbstractFunctionDecl>(decl)) {
     return afd->getInterfaceType()
       ->getAs<AnyFunctionType>()
@@ -192,7 +198,25 @@ static bool usesFeatureLifetimeDependence(Decl *decl) {
 }
 
 static bool usesFeatureLifetimes(Decl *decl) {
-  return findUnderscoredLifetimeAttr(decl);
+  if (findLifetimeAttr(decl, /*findUnderscored*/ true)) {
+    return true;
+  }
+
+  // Guard inferred lifetime dependencies with Lifetimes if it was enabled.
+  if (!decl->getASTContext().LangOpts.hasFeature(Feature::Lifetimes)) {
+    return false;
+  }
+
+  // Check for inferred lifetime dependencies
+  if (auto *afd = dyn_cast<AbstractFunctionDecl>(decl)) {
+    return afd->getInterfaceType()
+        ->getAs<AnyFunctionType>()
+        ->hasLifetimeDependencies();
+  }
+  if (auto *varDecl = dyn_cast<VarDecl>(decl)) {
+    return !varDecl->getTypeInContext()->isEscapable();
+  }
+  return false;
 }
 
 static bool usesFeatureInoutLifetimeDependence(Decl *decl) {
diff --git a/test/ModuleInterface/Inputs/lifetime_underscored_dependence.swift b/test/ModuleInterface/Inputs/lifetime_underscored_dependence.swift
index bf9407c784652..9fe204db4b5ec 100644
--- a/test/ModuleInterface/Inputs/lifetime_underscored_dependence.swift
+++ b/test/ModuleInterface/Inputs/lifetime_underscored_dependence.swift
@@ -77,3 +77,15 @@ extension Container {
     }
   }
 }
+
+public struct RigidArray : ~Copyable {
+  @usableFromInline let _ptr: UnsafeRawBufferPointer
+
+  public var span: RawSpan {
+    @_lifetime(borrow self)
+    get {
+      return RawSpan(_unsafeBytes: _ptr)
+    }
+  }
+}
+
diff --git a/test/ModuleInterface/lifetime_underscored_dependence_test.swift b/test/ModuleInterface/lifetime_underscored_dependence_test.swift
index 5ebbab3c2a567..4e6aeba094aa7 100644
--- a/test/ModuleInterface/lifetime_underscored_dependence_test.swift
+++ b/test/ModuleInterface/lifetime_underscored_dependence_test.swift
@@ -2,7 +2,6 @@
 
 // RUN: %target-swift-frontend -swift-version 5 -enable-library-evolution -emit-module \
 // RUN:     -enable-experimental-feature Lifetimes \
-// RUN:     -enable-experimental-feature Lifetimes \
 // RUN:     -o %t/lifetime_underscored_dependence.swiftmodule \
 // RUN:     -emit-module-interface-path %t/lifetime_underscored_dependence.swiftinterface \
 // RUN:     %S/Inputs/lifetime_underscored_dependence.swift
@@ -105,8 +104,22 @@ import lifetime_underscored_dependence
 // CHECK:}
 // CHECK:#endif
 
-// Check that an implicitly dependent variable accessor is guarded by LifetimeDependence.
-//
 // CHECK: extension lifetime_underscored_dependence.Container {
-// CHECK-NEXT: #if compiler(>=5.3) && $LifetimeDependence
+// CHECK-NEXT: #if compiler(>=5.3) && $Lifetimes
 // CHECK-NEXT:   public var storage: lifetime_underscored_dependence.BufferView {
+
+// CHECK: public struct RigidArray : ~Swift.Copyable {
+// CHECK:   @usableFromInline
+// CHECK:   internal let _ptr: Swift.UnsafeRawBufferPointer
+// CHECK:   #if compiler(>=5.3) && $Lifetimes
+// CHECK:   public var span: Swift.RawSpan {
+// CHECK:     @_lifetime(borrow self)
+// CHECK:     get
+// CHECK:   }
+// CHECK:   #else
+// CHECK:   public var span: Swift.RawSpan {
+// CHECK:     @lifetime(borrow self)
+// CHECK:     get
+// CHECK:   }
+// CHECK:   #endif
+// CHECK: }