From a86fe4fa30b22182aff7e8f58ae302b99918e3f6 Mon Sep 17 00:00:00 2001
From: Andrew Trick <atrick@apple.com>
Date: Mon, 7 Apr 2025 17:45:35 -0700
Subject: [PATCH 1/2] Add a "lazy" lifetime inference for mutating interface
 methods

When type checking a .swiftinterface file, Assume that a mutating methods does
not depend on its parameters.  This is unsafe but needed because some
MutableSpan APIs snuck into the standard library interface without specifying
dependencies.

Fixes rdar://148697444 error: a mutating method with a ~Escapable 'self' requires '@lifetime(self:
...)'
---
 lib/AST/LifetimeDependence.cpp                 | 18 ++++++++++++++++++
 .../lifetime_depend_infer.swiftinterface       | 12 ++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/lib/AST/LifetimeDependence.cpp b/lib/AST/LifetimeDependence.cpp
index d64e3d2576046..964e3b5dfa145 100644
--- a/lib/AST/LifetimeDependence.cpp
+++ b/lib/AST/LifetimeDependence.cpp
@@ -1069,6 +1069,13 @@ class LifetimeDependenceChecker {
       return;
     }
     if (afd->getParameters()->size() > 0) {
+      if (useLazyInference()) {
+        // Assume that a mutating method does not depend on its parameters.
+        // This is unsafe but needed because some MutableSpan APIs snuck into
+        // the standard library interface without specifying dependencies.
+        pushDeps(createDeps(selfIndex).add(selfIndex,
+                                           LifetimeDependenceKind::Inherit));
+      }
       return;
     }
     pushDeps(createDeps(selfIndex).add(selfIndex,
@@ -1115,6 +1122,17 @@ class LifetimeDependenceChecker {
                    .add(newValIdx, *kind));
       break;
     }
+    case AccessorKind::MutableAddress:
+      if (useLazyInference()) {
+        // Assume that a mutating method does not depend on its parameters.
+        // Currently only for backward interface compatibility. Even though this
+        // is the only useful dependence (a borrow of self is possible but not
+        // useful), explicit annotation is required for now to confirm that the
+        // mutated self cannot depend on anything stored at this address.
+        pushDeps(createDeps(selfIndex).add(selfIndex,
+                                           LifetimeDependenceKind::Inherit));
+      }
+      break;
     default:
       // Unknown mutating accessor.
       break;
diff --git a/test/Sema/Inputs/lifetime_depend_infer.swiftinterface b/test/Sema/Inputs/lifetime_depend_infer.swiftinterface
index f7982508c5773..14017799cc816 100644
--- a/test/Sema/Inputs/lifetime_depend_infer.swiftinterface
+++ b/test/Sema/Inputs/lifetime_depend_infer.swiftinterface
@@ -71,6 +71,18 @@ public struct NonEscapableSelf : ~Swift.Escapable {
   public mutating func mutatingMethodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
   #endif
 }
+
+public struct NoncopyableInoutMethods : ~Swift.Copyable & ~Swift.Escapable {
+#if $LifetimeDependence
+public mutating func mutatingMethodOneParamFunctionType<E, Result>(_ body: (Swift.Int) throws(E) -> Result) throws(E) -> Result where E : Swift.Error, Result : ~Swift.Copyable
+
+public subscript(position: Swift.Int) -> Swift.Int {
+  unsafeAddress
+  unsafeMutableAddress
+}
+#endif
+}
+
 public struct EscapableTrivialSelf {
   #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
   @lifetime(self)

From 7613c5e52e684ffd250edf297bdd87bd5d436f5a Mon Sep 17 00:00:00 2001
From: Andrew Trick <atrick@apple.com>
Date: Mon, 7 Apr 2025 18:11:12 -0700
Subject: [PATCH 2/2] [NFC] cleanup feature flags in
 lifetime_depend_infer.swiftinterface

---
 .../lifetime_depend_infer.swiftinterface      | 239 ++++++------------
 1 file changed, 83 insertions(+), 156 deletions(-)

diff --git a/test/Sema/Inputs/lifetime_depend_infer.swiftinterface b/test/Sema/Inputs/lifetime_depend_infer.swiftinterface
index 14017799cc816..95ed90aaca1a7 100644
--- a/test/Sema/Inputs/lifetime_depend_infer.swiftinterface
+++ b/test/Sema/Inputs/lifetime_depend_infer.swiftinterface
@@ -6,359 +6,286 @@ import Swift
 import _Concurrency
 import _StringProcessing
 import _SwiftConcurrencyShims
+
 @_hasMissingDesignatedInitializers public class C {}
+
+#if $LifetimeDependence
 public struct NE : ~Swift.Escapable {
 }
 public struct NEImmortal : ~Swift.Escapable {
-  #if $LifetimeDependence
   @lifetime(immortal)
   public init()
-  #endif
+
 }
+
 public struct NonEscapableSelf : ~Swift.Escapable {
-  #if $LifetimeDependence
   public func methodNoParam() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(self)
   public func methodNoParamLifetime() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(copy self)
   public func methodNoParamCopy() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(borrow self)
   public func methodNoParamBorrow() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(self)
   public mutating func mutatingMethodNoParamLifetime() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(copy self)
   public mutating func mutatingMethodNoParamCopy() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(&self)
   public mutating func mutatingMethodNoParamBorrow() -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   public func methodOneParam(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(self)
   public func methodOneParamLifetime(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(copy self)
   public func methodOneParamCopy(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(borrow self)
   public func methodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(self)
   public mutating func mutatingMethodOneParamLifetime(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(copy self)
   public mutating func mutatingMethodOneParamCopy(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(&self)
-  public mutating func mutatingMethodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf
-  #endif
+  public mutating func mutatingMethodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NonEscapableSelf 
 }
 
 public struct NoncopyableInoutMethods : ~Swift.Copyable & ~Swift.Escapable {
-#if $LifetimeDependence
-public mutating func mutatingMethodOneParamFunctionType<E, Result>(_ body: (Swift.Int) throws(E) -> Result) throws(E) -> Result where E : Swift.Error, Result : ~Swift.Copyable
+  public mutating func mutatingMethodOneParamFunctionType<E, Result>(_ body: (Swift.Int) throws(E) -> Result) throws(E) -> Result where E : Swift.Error, Result : ~Swift.Copyable
 
-public subscript(position: Swift.Int) -> Swift.Int {
-  unsafeAddress
-  unsafeMutableAddress
-}
-#endif
+  public subscript(position: Swift.Int) -> Swift.Int {
+    unsafeAddress
+    unsafeMutableAddress
+  }
 }
 
 public struct EscapableTrivialSelf {
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
   @lifetime(self)
   public func methodNoParamLifetime() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(borrow self)
   public func methodNoParamBorrow() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(self)
   public mutating func mutatingMethodNoParamLifetime() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(&self)
   public mutating func mutatingMethodNoParamBorrow() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(self)
   public func methodOneParamLifetime(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(borrow self)
   public func methodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(self)
   public mutating func mutatingMethodOneParamLifetime(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(&self)
   public mutating func mutatingMethodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
+  
 }
 public struct EscapableNonTrivialSelf {
   public init(c: lifetime_depend_infer.C)
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
   public func methodNoParam() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(self)
   public func methodNoParamLifetime() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(borrow self)
   public func methodNoParamBorrow() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   public func mutatingMethodNoParam() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(self)
   public mutating func mutatingMethodNoParamLifetime() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(&self)
   public mutating func mutatingMethodNoParamBorrow() -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   public func methodOneParam(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(self)
   public func methodOneParamLifetime(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(borrow self)
   public func methodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   public mutating func mutatingMethodOneParam(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(self)
   public mutating func mutatingMethodOneParamLifetime(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
-  #if compiler(>=5.3) && $NonescapableTypes && $LifetimeDependence
+  
   @lifetime(&self)
   public mutating func mutatingMethodOneParamBorrow(_: Swift.Int) -> lifetime_depend_infer.NEImmortal
-  #endif
+  
 }
 public struct NonescapableInitializers : ~Swift.Escapable {
   public var c: lifetime_depend_infer.C
-  #if $LifetimeDependence
   public init(ne: lifetime_depend_infer.NE)
-  #endif
+  
 }
 public struct NonescapableConsumingInitializers : ~Swift.Escapable {
   public var c: lifetime_depend_infer.C
-  #if $LifetimeDependence
   public init(ne: consuming lifetime_depend_infer.NE)
-  #endif
+  
 }
 public struct NonescapableBorrowingInitializers : ~Swift.Escapable {
   public var c: lifetime_depend_infer.C
-  #if $LifetimeDependence
   public init(c: borrowing lifetime_depend_infer.C)
-  #endif
-  #if $LifetimeDependence
+  
   public init(c: borrowing lifetime_depend_infer.C, _: Swift.Int)
-  #endif
-  #if $LifetimeDependence
+  
   public init(ne: borrowing lifetime_depend_infer.NE)
-  #endif
+  
 }
 public struct NonescapableInoutInitializers : ~Swift.Escapable {
   public var c: lifetime_depend_infer.C
-  #if $LifetimeDependence
   public init(c: inout lifetime_depend_infer.C)
-  #endif
+  
 }
-#if $LifetimeDependence
 @lifetime(immortal)
 public func noParamImmortal() -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
+
 @lifetime(c)
 public func oneParamLifetime(c: lifetime_depend_infer.C) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
+
 public func oneParamBorrow(c: borrowing lifetime_depend_infer.C) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
+
 @lifetime(c)
 public func oneParamBorrowLifetime(c: borrowing lifetime_depend_infer.C) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
+
 public func oneParamInout(c: inout lifetime_depend_infer.C) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
+
 @lifetime(c)
 public func oneParamInoutLifetime(c: inout lifetime_depend_infer.C) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
+
 @lifetime(c)
 public func twoParamsLifetime(c: lifetime_depend_infer.C, _: Swift.Int) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
+
 public func twoParamsBorrow(c: borrowing lifetime_depend_infer.C, _: Swift.Int) -> lifetime_depend_infer.NEImmortal
-#endif
-#if $LifetimeDependence
+
 public func neParam(ne: lifetime_depend_infer.NE) -> lifetime_depend_infer.NE
-#endif
-#if $LifetimeDependence
+
 @lifetime(ne)
 public func neParamLifetime(ne: lifetime_depend_infer.NE) -> lifetime_depend_infer.NE
-#endif
-#if $LifetimeDependence
+
 public func neParamBorrow(ne: borrowing lifetime_depend_infer.NE) -> lifetime_depend_infer.NE
-#endif
-#if $LifetimeDependence
+
 @lifetime(ne)
 public func neParamBorrowLifetime(ne: borrowing lifetime_depend_infer.NE) -> lifetime_depend_infer.NE
-#endif
-#if $LifetimeDependence
+
 public func neParamConsume(ne: consuming lifetime_depend_infer.NE) -> lifetime_depend_infer.NE
-#endif
-#if $LifetimeDependence
+
 @lifetime(ne)
 public func neParamConsumeLifetime(ne: consuming lifetime_depend_infer.NE) -> lifetime_depend_infer.NE
-#endif
-#if $LifetimeDependence
+
 public func neTwoParam(ne: lifetime_depend_infer.NE, _: Swift.Int) -> lifetime_depend_infer.NE
-#endif
+
 public struct Accessors {
-  #if $LifetimeDependence
   public var neYielded: lifetime_depend_infer.NEImmortal {
     _read
     _modify
   }
-  #endif
+  
 }
 public struct NonescapableSelfAccessors : ~Swift.Escapable {
   public var ne: lifetime_depend_infer.NE
-  #if $LifetimeDependence
   public init(ne: lifetime_depend_infer.NE)
-  #endif
-  #if $LifetimeDependence
+  
   public var neComputed: lifetime_depend_infer.NE {
     get
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neYielded: lifetime_depend_infer.NE {
     _read
     @lifetime(&self)
     _modify
   }
-  #endif
+  
 }
 public struct NoncopyableSelfAccessors : ~Copyable & ~Escapable {
   public var ne: lifetime_depend_infer.NE
-  #if $LifetimeDependence
   public var neComputed: lifetime_depend_infer.NE {
     get
     set
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neYielded: lifetime_depend_infer.NE {
     _read
     @lifetime(&self)
     _modify
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neComputedLifetime: lifetime_depend_infer.NE {
     @lifetime(self)
     get
     @lifetime(self)
     set
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neYieldedLifetime: lifetime_depend_infer.NE {
     @lifetime(self)
     _read
     @lifetime(self)
     _modify
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neComputedCopy: lifetime_depend_infer.NE {
     @lifetime(copy self)
     get
     @lifetime(copy self)
     set
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neYieldedCopy: lifetime_depend_infer.NE {
     @lifetime(copy self)
     _read
     @lifetime(copy self)
     _modify
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neComputedBorrow: lifetime_depend_infer.NE {
     @lifetime(borrow self)
     get
     @lifetime(&self)
     set
   }
-  #endif
-  #if $LifetimeDependence
+  
   public var neYieldedBorrow: lifetime_depend_infer.NE {
     @lifetime(borrow self)
     _read
     @lifetime(&self)
     _modify
   }
-  #endif
 }
+
 public struct NonEscapableMutableSelf : ~Swift.Escapable {
-  #if $LifetimeDependence
   public mutating func mutatingMethodNoParam()
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(self: self)
   public mutating func mutatingMethodNoParamLifetime()
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(self: copy self)
   public mutating func mutatingMethodNoParamCopy()
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(self: self)
   public mutating func mutatingMethodOneParamLifetime(_: lifetime_depend_infer.NE)
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(copy self)
   public mutating func mutatingMethodOneParamCopy(_: lifetime_depend_infer.NE)
-  #endif
-  #if $LifetimeDependence
+  
   @lifetime(&self)
   public mutating func mutatingMethodOneParamBorrow(_: lifetime_depend_infer.NE)
-  #endif
 }
+#endif