Sema: Teach ExportContext to compute whether we're inside a deprecate…

…d declaration

lib/Sema/TypeCheckAccess.cpp

@@ -1513,7 +1513,7 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
       loc = varDecl->getNameLoc();
 
     diagnoseTypeAvailability(typeRepr, type, loc,
-                             Where.forReason(reason), flags);
+                             Where.withReason(reason), flags);
   }
 
   void checkGenericParams(const GenericContext *ownerCtx,
@@ -1751,14 +1751,14 @@ class DeclAvailabilityChecker : public DeclVisitor<DeclAvailabilityChecker> {
       return isExported(valueMember);
     });
 
-    Where = wasWhere.forExported(hasExportedMembers);
-    checkType(ED->getExtendedType(),  ED->getExtendedTypeRepr(), ED,
+    Where = wasWhere.withExported(hasExportedMembers);
+    checkType(ED->getExtendedType(), ED->getExtendedTypeRepr(), ED,
               ExportabilityReason::ExtensionWithPublicMembers);
 
     // 3) If the extension contains exported members or defines conformances,
     // the 'where' clause must only name exported types.
-    Where = wasWhere.forExported(hasExportedMembers ||
-                                 !ED->getInherited().empty());
+    Where = wasWhere.withExported(hasExportedMembers ||
+                                  !ED->getInherited().empty());
     checkConstrainedExtensionRequirements(ED, hasExportedMembers);
   }
 

lib/Sema/TypeCheckAvailability.cpp

@@ -38,10 +38,11 @@
 using namespace swift;
 
 ExportContext::ExportContext(DeclContext *DC, FragileFunctionKind kind,
-                             bool spi, bool exported)
+                             bool spi, bool exported, bool deprecated)
     : DC(DC), FragileKind(kind) {
   SPI = spi;
   Exported = exported;
+  Deprecated = deprecated;
   Reason = ExportabilityReason::General;
 }
 
@@ -95,7 +96,73 @@ bool swift::isExported(const Decl *D) {
   return true;
 }
 
+template<typename Fn>
+static void forEachOuterDecl(DeclContext *DC, Fn fn) {
+  for (; !DC->isModuleScopeContext(); DC = DC->getParent()) {
+    switch (DC->getContextKind()) {
+    case DeclContextKind::AbstractClosureExpr:
+    case DeclContextKind::TopLevelCodeDecl:
+    case DeclContextKind::SerializedLocal:
+    case DeclContextKind::Module:
+    case DeclContextKind::FileUnit:
+      break;
+
+    case DeclContextKind::Initializer:
+      if (auto *PBI = dyn_cast<PatternBindingInitializer>(DC))
+        fn(PBI->getBinding());
+      break;
+
+    case DeclContextKind::SubscriptDecl:
+      fn(cast<SubscriptDecl>(DC));
+      break;
+
+    case DeclContextKind::EnumElementDecl:
+      fn(cast<EnumElementDecl>(DC));
+      break;
+
+    case DeclContextKind::AbstractFunctionDecl:
+      fn(cast<AbstractFunctionDecl>(DC));
+
+      if (auto *AD = dyn_cast<AccessorDecl>(DC))
+        fn(AD->getStorage());
+      break;
+
+    case DeclContextKind::GenericTypeDecl:
+      fn(cast<GenericTypeDecl>(DC));
+      break;
+
+    case DeclContextKind::ExtensionDecl:
+      fn(cast<ExtensionDecl>(DC));
+      break;
+    }
+  }
+}
+
+static void computeExportContextBits(Decl *D,
+                                     bool *implicit, bool *deprecated) {
+  if (D->isImplicit())
+    *implicit = true;
+
+  if (D->getAttrs().getDeprecated(D->getASTContext()))
+    *deprecated = true;
+
+  if (auto *PBD = dyn_cast<PatternBindingDecl>(D)) {
+    for (unsigned i = 0, e = PBD->getNumPatternEntries(); i < e; ++i) {
+      if (auto *VD = PBD->getAnchoringVarDecl(i))
+        computeExportContextBits(VD, implicit, deprecated);
+    }
+  }
+}
+
 ExportContext ExportContext::forDeclSignature(Decl *D) {
+  bool implicit = false;
+  bool deprecated = false;
+  computeExportContextBits(D, &implicit, &deprecated);
+  forEachOuterDecl(D->getDeclContext(),
+                   [&](Decl *D) {
+                     computeExportContextBits(D, &implicit, &deprecated);
+                   });
+
   auto *DC = D->getInnermostDeclContext();
   auto fragileKind = DC->getFragileFunctionKind();
 
@@ -113,11 +180,19 @@ ExportContext ExportContext::forDeclSignature(Decl *D) {
 
   bool exported = ::isExported(D);
 
-  return ExportContext(DC, fragileKind, spi, exported);
+  return ExportContext(DC, fragileKind, spi, exported, deprecated);
 }
 
 ExportContext ExportContext::forFunctionBody(DeclContext *DC) {
-  ;
+  assert(DC && "Use ExportContext::forImplicit() for implicit decls");
+
+  bool implicit = false;
+  bool deprecated = false;
+  forEachOuterDecl(DC,
+                   [&](Decl *D) {
+                     computeExportContextBits(D, &implicit, &deprecated);
+                   });
+
   auto fragileKind = DC->getFragileFunctionKind();
 
   bool spi = false;
@@ -129,16 +204,21 @@ ExportContext ExportContext::forFunctionBody(DeclContext *DC) {
     assert(fragileKind.kind == FragileFunctionKind::None);
   }
 
-  return ExportContext(DC, fragileKind, spi, exported);
+  return ExportContext(DC, fragileKind, spi, exported, deprecated);
+}
+
+ExportContext ExportContext::forImplicit() {
+  return ExportContext(nullptr, FragileFunctionKind(),
+                       false, false, false);
 }
 
-ExportContext ExportContext::forReason(ExportabilityReason reason) const {
+ExportContext ExportContext::withReason(ExportabilityReason reason) const {
   auto copy = *this;
   copy.Reason = reason;
   return copy;
 }
 
-ExportContext ExportContext::forExported(bool exported) const {
+ExportContext ExportContext::withExported(bool exported) const {
   auto copy = *this;
   copy.Exported = isExported() && exported;
   return copy;
@@ -1672,17 +1752,6 @@ static bool isInsideCompatibleUnavailableDeclaration(
   return someEnclosingDeclMatches(ReferenceRange, ReferenceDC, IsUnavailable);
 }
 
-/// Returns true if the reference is lexically contained in a declaration
-/// that is deprecated on all deployment targets.
-static bool isInsideDeprecatedDeclaration(SourceRange ReferenceRange,
-                                          const DeclContext *ReferenceDC){
-  auto IsDeprecated = [](const Decl *D) {
-    return D->getAttrs().getDeprecated(D->getASTContext());
-  };
-
-  return someEnclosingDeclMatches(ReferenceRange, ReferenceDC, IsDeprecated);
-}
-
 static void fixItAvailableAttrRename(InFlightDiagnostic &diag,
                                      SourceRange referenceRange,
                                      const ValueDecl *renamedDecl,
@@ -2059,13 +2128,15 @@ getAccessorKindAndNameForDiagnostics(const ValueDecl *D) {
 }
 
 void TypeChecker::diagnoseIfDeprecated(SourceRange ReferenceRange,
-                                       const DeclContext *ReferenceDC,
+                                       ExportContext Where,
                                        const ValueDecl *DeprecatedDecl,
                                        const ApplyExpr *Call) {
   const AvailableAttr *Attr = TypeChecker::getDeprecated(DeprecatedDecl);
   if (!Attr)
     return;
 
+  auto *ReferenceDC = Where.getDeclContext();
+
   // We don't want deprecated declarations to trigger warnings
   // in synthesized code.
   if (ReferenceRange.isInvalid() &&
@@ -2075,7 +2146,7 @@ void TypeChecker::diagnoseIfDeprecated(SourceRange ReferenceRange,
   // We match the behavior of clang to not report deprecation warnings
   // inside declarations that are themselves deprecated on all deployment
   // targets.
-  if (isInsideDeprecatedDeclaration(ReferenceRange, ReferenceDC)) {
+  if (Where.isDeprecated()) {
     return;
   }
 
@@ -2788,7 +2859,7 @@ AvailabilityWalker::diagAvailability(ConcreteDeclRef declRef, SourceRange R,
 
   // Diagnose for deprecation
   if (!isAccessorWithDeprecatedStorage)
-    TypeChecker::diagnoseIfDeprecated(R, DC, D, call);
+    TypeChecker::diagnoseIfDeprecated(R, Where, D, call);
 
   if (Flags.contains(DeclAvailabilityFlag::AllowPotentiallyUnavailable))
     return false;

lib/Sema/TypeCheckAvailability.h

@@ -97,9 +97,11 @@ class ExportContext {
   FragileFunctionKind FragileKind;
   unsigned SPI : 1;
   unsigned Exported : 1;
+  unsigned Deprecated : 1;
   ExportabilityReason Reason;
 
-  ExportContext(DeclContext *DC, FragileFunctionKind kind, bool spi, bool exported);
+  ExportContext(DeclContext *DC, FragileFunctionKind kind,
+                bool spi, bool exported, bool deprecated);
 
 public:
 
@@ -119,30 +121,46 @@ class ExportContext {
   /// it can reference anything.
   static ExportContext forFunctionBody(DeclContext *DC);
 
+  /// Produce a new context describing an implicit declaration. Implicit code
+  /// does not have source locations. We simply trust the compiler synthesizes
+  /// implicit declarations correctly, and skip the checks.
+  static ExportContext forImplicit();
+
   /// Produce a new context with the same properties as this one, except
   /// changing the ExportabilityReason. This only affects diagnostics.
-  ExportContext forReason(ExportabilityReason reason) const;
+  ExportContext withReason(ExportabilityReason reason) const;
 
   /// Produce a new context with the same properties as this one, except
   /// that if 'exported' is false, the resulting context can reference
   /// declarations that are not exported. If 'exported' is true, the
   /// resulting context is indentical to this one.
   ///
   /// That is, this will perform a 'bitwise and' on the 'exported' bit.
-  ExportContext forExported(bool exported) const;
+  ExportContext withExported(bool exported) const;
 
-  DeclContext *getDeclContext() const { return DC; }
+  DeclContext *getDeclContext() const {
+    assert(DC != nullptr && "This is an implicit context");
+    return DC;
+  }
 
   /// If not 'None', the context has the inlinable function body restriction.
   FragileFunctionKind getFragileFunctionKind() const { return FragileKind; }
 
+  /// If true, the context is part of a synthesized declaration, and
+  /// availability checking should be disabled.
+  bool isImplicit() const { return DC == nullptr; }
+
   /// If true, the context is SPI and can reference SPI declarations.
   bool isSPI() const { return SPI; }
 
   /// If true, the context is exported and cannot reference SPI declarations
   /// or declarations from `@_implementationOnly` imports.
   bool isExported() const { return Exported; }
 
+  /// If true, the context is part of a deprecated declaration and can
+  /// reference other deprecated declarations without warning.
+  bool isDeprecated() const { return Deprecated; }
+
   /// If true, the context can only reference exported declarations, either
   /// because it is the signature context of an exported declaration, or
   /// because it is the function body context of an inlinable function.

lib/Sema/TypeChecker.h

@@ -1047,7 +1047,7 @@ const AvailableAttr *getDeprecated(const Decl *D);
 /// Callers can provide a lambda that adds additional information (such as a
 /// fixit hint) to the deprecation diagnostic, if it is emitted.
 void diagnoseIfDeprecated(SourceRange SourceRange,
-                          const DeclContext *ReferenceDC,
+                          ExportContext Where,
                           const ValueDecl *DeprecatedDecl,
                           const ApplyExpr *Call);
 /// @}

test/Sema/availability_deprecated.swift

@@ -0,0 +1,42 @@
+// RUN: %target-typecheck-verify-swift -parse-as-library
+
+struct DummyType {}
+
+@available(*, deprecated, renamed: "&-")
+func -(x: DummyType, y: DummyType) {}
+
+// We don't warn if a deprecated declaration is referenced from
+// within another deprecated declaration.
+
+@available(*, deprecated)
+func testDeprecatedReferencingDeprecated1(x: DummyType, y: DummyType) {
+  x - y // no-warning
+}
+
+@available(*, deprecated)
+var testDeprecatedReferencingDeprecated2: () {
+  let x = DummyType()
+  let y = DummyType()
+  x - y // no-warning
+}
+
+// FIXME: This doesn't work because the file is parsed in script mode.
+@available(*, deprecated)
+var testDeprecatedReferencingDeprecated3: () = DummyType() - DummyType() // no-warning
+
+struct HasDeprecatedMembers {
+  @available(*, deprecated)
+  func testDeprecatedReferencingDeprecated1(x: DummyType, y: DummyType) {
+    x - y // no-warning
+  }
+
+  @available(*, deprecated)
+  var testDeprecatedReferencingDeprecated2: () {
+    let x = DummyType()
+    let y = DummyType()
+    x - y // no-warning
+  }
+
+  @available(*, deprecated)
+  var testDeprecatedReferencingDeprecated3: () = DummyType() - DummyType() // no-warning
+}

test/Sema/availability_deprecated_script_mode.swift

@@ -0,0 +1,44 @@
+// RUN: %target-typecheck-verify-swift
+
+// We don't warn if a deprecated declaration is referenced from
+// within another deprecated declaration.
+
+struct DummyType {}
+
+@available(*, deprecated, renamed: "&-")
+func -(x: DummyType, y: DummyType) {}
+
+@available(*, deprecated)
+func testDeprecatedReferencingDeprecated1(x: DummyType, y: DummyType) {
+  x - y // no-warning
+}
+
+@available(*, deprecated)
+var testDeprecatedReferencingDeprecated2: () {
+  let x = DummyType()
+  let y = DummyType()
+  x - y // no-warning
+}
+
+// FIXME: This doesn't work because the file is parsed in script mode.
+@available(*, deprecated)
+var testDeprecatedReferencingDeprecated3: () = DummyType() - DummyType()
+// expected-warning@-1 {{'-' is deprecated}}
+// expected-note@-2 {{use '&-' instead}}
+
+struct HasDeprecatedMembers {
+  @available(*, deprecated)
+  func testDeprecatedReferencingDeprecated1(x: DummyType, y: DummyType) {
+    x - y // no-warning
+  }
+
+  @available(*, deprecated)
+  var testDeprecatedReferencingDeprecated2: () {
+    let x = DummyType()
+    let y = DummyType()
+    x - y // no-warning
+  }
+
+  @available(*, deprecated)
+  var testDeprecatedReferencingDeprecated3: () = DummyType() - DummyType() // no-warning
+}