Merge pull request #66860 from jckarter/no-moveonly-property-descriptors

SILGen: Don't emit key path property descriptors for properties in or of noncopyable types.

Author: jckarter

lib/SIL/IR/SIL.cpp

@@ -300,6 +300,21 @@ bool AbstractStorageDecl::exportsPropertyDescriptor() const {
   // The storage needs a descriptor if it sits at a module's ABI boundary,
   // meaning it has public linkage.
 
+  // Noncopyable types aren't supported by key paths in their current form.
+  // They would also need a new ABI that's yet to be implemented in order to
+  // be properly supported, so let's suppress the descriptor for now if either
+  // the container or storage type of the declaration is non-copyable.
+  if (getValueInterfaceType()->isPureMoveOnly()) {
+    return false;
+  }
+  if (!isStatic()) {
+    if (auto contextTy = getDeclContext()->getDeclaredTypeInContext()) {
+      if (contextTy->isPureMoveOnly()) {
+        return false;
+      }
+    }
+  }
+  
   // TODO: Global and static properties ought to eventually be referenceable
   // as key paths from () or T.Type too.
   if (!getDeclContext()->isTypeContext() || isStatic())

test/SILGen/no_property_descriptor_for_move_only.swift

@@ -0,0 +1,69 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-emit-silgen %s > %t/fragile-out.sil
+// %FileCheck --check-prefix=POS %s < %t/fragile-out.sil
+// %FileCheck --check-prefix=NEG %s < %t/fragile-out.sil
+// RUN: %target-swift-emit-silgen -enable-library-evolution %s > %t/resilient-out.sil
+// %FileCheck --check-prefix=POS %s < %t/resilient-out.sil
+// %FileCheck --check-prefix=NEG %s < %t/resilient-out.sil
+
+@frozen
+public struct IsCopyable {
+    public init() {}
+
+    // Shouldn't get a property descriptor since property type is noncopyable
+    // NEG-NOT: sil_property #IsCopyable.noncopyable
+    public var noncopyable: IsntCopyable {
+        get { IsntCopyable() }
+        set { }
+    }
+
+    // Should get a property descriptor, copyable container and property
+    // POS: sil_property #IsCopyable.copyable
+    public var copyable: IsCopyable {
+        get { IsCopyable() }
+        set { }
+    }
+
+    // Shouldn't get a property descriptor since it's static
+    // NEG-NOT: sil_property #IsCopyable.staticCopyable
+    public static var staticCopyable: IsCopyable = IsCopyable()
+
+    // Shouldn't get a property descriptor since it's static
+    // NEG-NOT: sil_property #IsCopyable.staticNoncopyable
+    public static var staticNoncopyable: IsntCopyable = IsntCopyable()
+}
+
+@frozen
+public struct IsntCopyable: ~Copyable {
+    public init() {}
+
+    // Shouldn't get a property descriptor since container and property type are both noncopyable
+    // NEG-NOT: sil_property #IsntCopyable.noncopyable
+    public var noncopyable: IsntCopyable {
+        get { IsntCopyable() }
+        set { }
+    }
+
+    // Shouldn't get a property descriptor since container type is noncopyable
+    // NEG-NOT: sil_property #IsntCopyable.copyable
+    public var copyable: IsCopyable {
+        get { IsCopyable() }
+        set { }
+    }
+
+    // Shouldn't get a property descriptor since it's static
+    // NEG-NOT: sil_property #IsntCopyable.staticCopyable
+    public static var staticCopyable: IsCopyable = IsCopyable()
+
+    // Shouldn't get a property descriptor since it's static
+    // NEG-NOT: sil_property #IsntCopyable.staticNoncopyable
+    public static var staticNoncopyable: IsntCopyable = IsntCopyable()
+}
+
+// Shouldn't get a property descriptor since it's global
+// NEG-NOT: sil_property #{{.*}}globalCopyable
+public var globalCopyable: IsCopyable = IsCopyable()
+
+// Shouldn't get a property descriptor since it's global
+// NEG-NOT: sil_property #{{.*}}globalNoncopyable
+public var globalNoncopyable: IsntCopyable = IsntCopyable()