Merge pull request #73771 from kavon/6.0-tilde-copyable-printing-interface-rdar126090425

[6.0🍒] ASTPrinter: handle inverses in compositions

Author: kavon

lib/AST/ASTPrinter.cpp

@@ -7868,7 +7868,24 @@ swift::getInheritedForPrinting(
   // Collect explicit inherited types.
   for (auto i : inherited.getIndices()) {
     if (auto ty = inherited.getResolvedType(i)) {
+      // Preserve inverses separately, because the `foundUnprintable` logic
+      // doesn't handle compositions with a mix of printable and unprintable
+      // types! That's handled later by `InheritedProtocolCollector`.
+      //
+      // Generally speaking, `getInheritedForPrinting` needs to be
+      // querying `InheritedProtocolCollector` to find out what protocols it
+      // should print in the inheritance clause, to reduce code duplication
+      // in the printer.
+      InvertibleProtocolSet printableInverses;
+
       bool foundUnprintable = ty.findIf([&](Type subTy) {
+        {
+          // We canonicalize the composition to ensure no inverses are missed.
+          auto subCanTy = subTy->getCanonicalType();
+          if (auto PCT = subCanTy->getAs<ProtocolCompositionType>()) {
+            printableInverses.insertAll(PCT->getInverses());
+          }
+        }
         if (auto aliasTy = dyn_cast<TypeAliasType>(subTy.getPointer()))
           return !options.shouldPrint(aliasTy->getDecl());
         if (auto NTD = subTy->getAnyNominal()) {
@@ -7877,8 +7894,22 @@ swift::getInheritedForPrinting(
         }
         return false;
       });
-      if (foundUnprintable)
+
+      // Preserve any inverses that appeared in the unprintable type.
+      if (foundUnprintable) {
+        if (printableInverses.contains(InvertibleProtocolKind::Copyable)
+            && options.SuppressNoncopyableGenerics)
+          printableInverses.remove(InvertibleProtocolKind::Copyable);
+
+        if (!printableInverses.empty()) {
+          auto inversesTy = ProtocolCompositionType::get(decl->getASTContext(),
+                                                         /*members=*/{},
+                                                         printableInverses,
+                                                         /*anyObject=*/false);
+          Results.push_back(InheritedEntry(TypeLoc::withoutLoc(inversesTy)));
+        }
         continue;
+      }
 
       // Suppress Copyable and ~Copyable.
       if (options.SuppressNoncopyableGenerics) {

test/ModuleInterface/Inputs/NoncopyableGenerics_Misc.swift

@@ -127,3 +127,13 @@ public func substCopyable(_ t: String?) {}
 public func substGenericCopyable<T>(_ t: T?) {}
 public func substNC(_ t: borrowing NoCopyPls?) {}
 public func substGenericNC<T: ~Copyable>(_ t: borrowing T?) {}
+
+// coverage for rdar://126090425
+protocol P : ~Copyable {} // NOTE: it's important that this is NOT public.
+protocol Q: ~Copyable {}  // NOTE: it's important that this is NOT public.
+public protocol Publik: ~Copyable {}
+public struct Concrete : (P & ~Copyable) {}
+public struct Generic<T: Publik & ~Copyable> : (P & ~Copyable) {}
+public struct VeryNested: (P & (Q & ~Copyable & Publik) & (P & ~Copyable)) {}
+public struct Twice: P & ~Copyable, Q & ~Copyable {}
+public struct RegularTwice: ~Copyable, ~Copyable {}

test/ModuleInterface/noncopyable_generics.swift

@@ -192,6 +192,31 @@ import NoncopyableGenerics_Misc
 // CHECK-MISC-NEXT: public func substGenericNC<T>(_ t: borrowing T?)
 // CHECK-MISC-NEXT: #endif
 
+// CHECK-MISC:      #if compiler(>=5.3) && $NoncopyableGenerics
+// CHECK-MISC-NEXT: public protocol Publik : ~Copyable {
+// CHECK-MISC-NEXT: }
+// CHECK-MISC-NEXT: #else
+// CHECK-MISC-NEXT: public protocol Publik {
+// CHECK-MISC-NEXT: }
+// CHECK-MISC-NEXT: #endif
+// CHECK-MISC-NEXT: public struct Concrete : ~Copyable {
+// CHECK-MISC-NEXT: }
+// CHECK-MISC-NEXT: #if compiler(>=5.3) && $NoncopyableGenerics
+// CHECK-MISC-NEXT: public struct Generic<T> : ~Copyable where T : {{.*}}.Publik, T : ~Copyable {
+// CHECK-MISC-NEXT: }
+// CHECK-MISC-NEXT: #else
+// CHECK-MISC-NEXT: public struct Generic<T> where T : {{.*}}.Publik {
+// CHECK-MISC-NEXT: }
+// CHECK-MISC-NEXT: #endif
+// CHECK-MISC-NEXT: public struct VeryNested : ~Copyable {
+// CHECK-MISC-NEXT: }
+// CHECK-MISC-NEXT: public struct Twice : ~Copyable, ~Copyable {
+// CHECK-MISC-NEXT: }
+// CHECK-MISC-NEXT: public struct RegularTwice : ~Swift.Copyable, ~Swift.Copyable {
+// CHECK-MISC-NEXT: }
+
+// NOTE: below are extensions emitted at the end of NoncopyableGenerics_Misc.swift
+// CHECK-MISC: extension {{.*}}.VeryNested : {{.*}}.Publik {}
 
 import Swiftskell