[ObjC Availability] Warn upon unguarded use of partially available declaration

[erik.pilkington]

Summary

This patch implements support for diagnostics for @available violations. This is done with a traversal of the AST after semantic analysis of a function where a partially available (based on availability attributes) use of a declaration is found. For example:

if (@available(macos 10.12, *))
  fn_10_12();
else
  fn_10_12(); // clang now emits a warning here

This patch also treats both branches of if (@available(...)) checks as begin protected; being able to goto into them would break this feature. Also, -Wpartial-availability is now an alias of -Wunguarded-availability.

Up next is a patch to implement clang CodeGen support for ObjCAvailabilityCheckExpr, and another to provide fixits to suggest using @available.

This patch is part of a series that implements the feature I proposed here:
http://lists.llvm.org/pipermail/cfe-dev/2016-July/049851.html

[dcoughlin]

It's really great to see this!

lib/Sema/SemaExpr.cpp

15200 ↗

(On Diff #66256)

In Swift we don't warn for this scenario and don't require the programmer to explicitly account for the current platform. The rationale behind '*' was to make platform bringup easier. Because new platforms are typically forked from existing platforms, treating '*' as the minimum deployment target on the current platform would typically do the "right thing" on new platforms. In cases where it doesn't, the user would still get a diagnostic if she tried to use a potentially unavailable API.

If I understand it correctly, with the behavior here anyone porting code to a new platform will get a warning for each @available. Is this what you want?

[erik.pilkington]

This new patch removes the warning diag::warn_available_using_star_case, as per Devin's suggestion.

[dcoughlin]

lib/Sema/SemaDeclAttr.cpp

6611 ↗

(On Diff #66501)

Do you still want to suppress warnings in the 'then' branch for '*'? I think there is potential value in pointing out uses of APIs that are not available on the minimum deployment target for the '*' case.

[erik.pilkington]

@dcoughlin: Yes, good point!

This new patch uses the enclosing version to diagnose both branches of the '*' case, as opposed to ignoring them.

[manmanren]

Hi Erik,

Thanks for working on this! It is great to see these patches coming.

Manman

include/clang/Sema/Sema.h

9608 ↗

(On Diff #66555)

Can you explain the inputs and outputs?

lib/Sema/SemaDeclAttr.cpp

6517 ↗

(On Diff #66555)

Can you add a high level description of what this class is doing to issue unguarded diagnostics?

6540 ↗

(On Diff #66555)

Do we cover all usage of decls with the above three member functions?

6552 ↗

(On Diff #66555)

It is easier to read if you add comment for the boolean argument.

6554 ↗

(On Diff #66555)

Can you mention where they are handled?

lib/Sema/SemaExpr.cpp

110 ↗

(On Diff #66555)

This looks like a refactoring of DiagnoseAvailabilityOfDecl. Is it possible to commit as a NFC patch?

test/SemaObjC/unguarded-availability.m

93 ↗

(On Diff #66555)

Should we emit error here? Or should we just ignore the tighter availability scope?

[erik.pilkington]

This new patch rebases on top of r277887, and addresses Manman's comments.

After looking through the AST nodes, I realized I neglected to emit a diagnostic for member expressions. I also noticed that function parameters are not being handled correctly. For example:

int f(introduced_in_10_12_t x) __attribute__((availability(macos, introduced=10.12)));

Triggers -Wunguarded-availability, which is clearly incorrect. I think the fix here is just to delay the diagnostic until we know the context availability. This isn't really related to this patch, so I'll fix it in a follow up.

Outside of that I can't think of any cases of referencing a declaration in a function body that we're missing.

Thanks!

[manmanren]

This looks pretty good. Can you add a few more testing cases for templates such as @available inside the template function, @available enclosing the template instantiation?

Cheers,
Manman

lib/Sema/SemaDeclAttr.cpp

6634 ↗

(On Diff #67582)

I wonder if it is better to combine this with the above if (!E->hasVersion()) i.e
if (!E->hasVersion() || E->getVersion() <= AvailabilityStack.back())

[erik.pilkington]

This new patch adds some testcases for templates, and simplifies some control flow in TraverseIfStmt. This patch also removes diagnostics for instantiated templates, instead just using the pattern. This means that a dependent type that was resolved during instantiation can refer to an unavailable declaration. For example, the following now compiles cleanly (when we want a diagnostic):

void f(int);
void f(char) __attribute__((availability(macos, introduced=10.12)));

template <class T> void use_f(T p) { f(p); }

template void use_f<char>();

This is done so containers, such as vector<partially_available> can be used safely provided partially_available is safe at the point of instantiation. I think the way to improve this is in Sema::getVersionForDecl(). There we could look at function and template parameters to determine the best base version, then diagnose against it.

[manmanren]

This is done so containers, such as vector<partially_available> can be used safely provided partially_available is safe at the point of instantiation. I think the way to improve this is in Sema::getVersionForDecl(). There we could look at function and template parameters to determine the best base version, then diagnose against it.

Let's fix the diagnostics for dependent type in a follow-up patch. And your suggestion above sounds reasonable to me.

Thanks for the work!
Manman

[thakis]

Erik, are you planning on adding the later phases soon? At the moment, due to this patch, clang emits "enclose 'setAllowsAutomaticWindowTabbing:' in an @available check to silence this warning" but then errors out when trying to use @available. This is proving to be confusing to folks :-)

cfe/trunk/include/clang/AST/Stmt.h

public:
   SourceLocation getIfLoc() const { return IfLoc; }
   void setIfLoc(SourceLocation L) { IfLoc = L; }
   SourceLocation getElseLoc() const { return ElseLoc; }
   void setElseLoc(SourceLocation L) { ElseLoc = L; }
 
   bool isConstexpr() const { return IfStmtBits.IsConstexpr; }
   void setConstexpr(bool C) { IfStmtBits.IsConstexpr = C; }
 
+  bool isObjCAvailabilityCheck() const;
+
   SourceLocation getLocStart() const LLVM_READONLY { return IfLoc; }
   SourceLocation getLocEnd() const LLVM_READONLY {
     if (SubExprs[ELSE])
       return SubExprs[ELSE]->getLocEnd();
     else
       return SubExprs[THEN]->getLocEnd();
   }
 

cfe/trunk/include/clang/Basic/DiagnosticGroups.td

 def AbstractFinalClass : DiagGroup<"abstract-final-class">;
 
 def CXX11CompatDeprecatedWritableStr :
   DiagGroup<"c++11-compat-deprecated-writable-strings">;
 
 def DeprecatedAttributes : DiagGroup<"deprecated-attributes">;
 def DeprecatedDeclarations : DiagGroup<"deprecated-declarations">;
 def UnavailableDeclarations : DiagGroup<"unavailable-declarations">;
-def PartialAvailability : DiagGroup<"partial-availability">;
 def UnguardedAvailability : DiagGroup<"unguarded-availability">;
+// partial-availability is an alias of unguarded-availability.
+def : DiagGroup<"partial-availability", [UnguardedAvailability]>;
 def DeprecatedImplementations :DiagGroup<"deprecated-implementations">;
 def DeprecatedIncrementBool : DiagGroup<"deprecated-increment-bool">;
 def DeprecatedRegister : DiagGroup<"deprecated-register">;
 def DeprecatedWritableStr : DiagGroup<"deprecated-writable-strings",
                                       [CXX11CompatDeprecatedWritableStr]>;
 // FIXME: Why is DeprecatedImplementations not in this group?
 def Deprecated : DiagGroup<"deprecated", [DeprecatedAttributes,
                                           DeprecatedDeclarations,

 
 def OptionIgnored : DiagGroup<"option-ignored">;
 
 def UnknownArgument : DiagGroup<"unknown-argument">;
 
 // A warning group for warnings about code that clang accepts when
 // compiling OpenCL C/C++ but which is not compatible with the SPIR spec.
 def SpirCompat : DiagGroup<"spir-compat">;
 No newline at end of file

cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td

def warn_mismatched_availability_override_unavail : Warning<
   "%select{the protocol method it implements|its overridden method}1 is "
   "available">,
   InGroup<Availability>;
 def note_overridden_method : Note<
   "overridden method is here">;
 def note_protocol_method : Note<
   "protocol method is here">;
 
-def warn_available_using_star_case : Warning<
-  "using '*' case here, platform %0 is not accounted for">, InGroup<UnguardedAvailability>;
+def warn_unguarded_availability :
+  Warning<"%0 is only available on %1 %2 or newer">,
+  InGroup<UnguardedAvailability>, DefaultIgnore;
+def warn_partial_availability : Warning<"%0 is only available conditionally">,
+    InGroup<UnguardedAvailability>, DefaultIgnore;
+def note_partial_availability_silence : Note<
+  "explicitly redeclare %0 to silence this warning">;
+def note_unguarded_available_silence : Note<
+  "enclose %0 in an @available check to silence this warning">;
+def warn_partial_message : Warning<"%0 is partial: %1">,
+    InGroup<UnguardedAvailability>, DefaultIgnore;
+def warn_partial_fwdclass_message : Warning<
+    "%0 may be partial because the receiver type is unknown">,
+    InGroup<UnguardedAvailability>, DefaultIgnore;
 
 // Thread Safety Attributes
 def warn_invalid_capability_name : Warning<
   "invalid capability name '%0'; capability name must be 'mutex' or 'role'">,
   InGroup<ThreadSafetyAttributes>, DefaultIgnore;
 def warn_thread_attribute_ignored : Warning<
   "ignoring %0 attribute because its argument is invalid">,
   InGroup<ThreadSafetyAttributes>, DefaultIgnore;
def ext_found_via_dependent_bases_lookup : ExtWarn<"use of identifier %0 "
   "Microsoft extension">, InGroup<MicrosoftTemplate>;
 def note_dependent_var_use : Note<"must qualify identifier to find this "
     "declaration in dependent base class">;
 def err_not_found_by_two_phase_lookup : Error<"call to function %0 that is neither "
     "visible in the template definition nor found by argument-dependent lookup">;
 def note_not_found_by_two_phase_lookup : Note<"%0 should be declared prior to the "
     "call site%select{| or in %2| or in an associated namespace of one of its arguments}1">;
 def err_undeclared_use : Error<"use of undeclared %0">;
-def warn_partial_availability : Warning<"%0 is only available conditionally">,
-    InGroup<PartialAvailability>, DefaultIgnore;
-def note_partial_availability_silence : Note<
-  "explicitly redeclare %0 to silence this warning">;
-def warn_partial_message : Warning<"%0 is partial: %1">,
-    InGroup<PartialAvailability>, DefaultIgnore;
-def warn_partial_fwdclass_message : Warning<
-    "%0 may be partial because the receiver type is unknown">,
-    InGroup<PartialAvailability>, DefaultIgnore;
 def warn_deprecated : Warning<"%0 is deprecated">,
     InGroup<DeprecatedDeclarations>;
 def warn_property_method_deprecated :
     Warning<"property access is using %0 method which is deprecated">,
     InGroup<DeprecatedDeclarations>;
 def warn_deprecated_message : Warning<"%0 is deprecated: %1">,
     InGroup<DeprecatedDeclarations>;
 def warn_deprecated_anonymous_namespace : Warning<

 def note_protected_by_cleanup : Note<
   "jump bypasses initialization of variable with __attribute__((cleanup))">;
 def note_protected_by_vla_typedef : Note<
   "jump bypasses initialization of VLA typedef">;
 def note_protected_by_vla_type_alias : Note<
   "jump bypasses initialization of VLA type alias">;
 def note_protected_by_constexpr_if : Note<
   "jump enters controlled statement of constexpr if">;
+def note_protected_by_if_available : Note<
+  "jump enters controlled statement of if available">;
 def note_protected_by_vla : Note<
   "jump bypasses initialization of variable length array">;
 def note_protected_by_objc_try : Note<
   "jump bypasses initialization of @try block">;
 def note_protected_by_objc_catch : Note<
   "jump bypasses initialization of @catch block">;
 def note_protected_by_objc_finally : Note<
   "jump bypasses initialization of @finally block">;

cfe/trunk/include/clang/Sema/ScopeInfo.h

public:
 
   /// \brief Whether this function contains any indirect gotos.
   bool HasIndirectGoto : 1;
 
   /// \brief Whether a statement was dropped because it was invalid.
   bool HasDroppedStmt : 1;
 
   /// \brief True if current scope is for OpenMP declare reduction combiner.
-  bool HasOMPDeclareReductionCombiner;
+  bool HasOMPDeclareReductionCombiner : 1;
 
   /// \brief Whether there is a fallthrough statement in this function.
   bool HasFallthroughStmt : 1;
 
+  /// \brief Whether we make reference to a declaration that could be
+  /// unavailable.
+  bool HasPotentialAvailabilityViolations : 1;
+
   /// A flag that is set when parsing a method that must call super's
   /// implementation, such as \c -dealloc, \c -finalize, or any method marked
   /// with \c __attribute__((objc_requires_super)).
   bool ObjCShouldCallSuper : 1;
 
   /// True when this is a method marked as a designated initializer.
   bool ObjCIsDesignatedInit : 1;
   /// This starts true for a method marked as designated initializer and will
public:
   FunctionScopeInfo(DiagnosticsEngine &Diag)
     : Kind(SK_Function),
       HasBranchProtectedScope(false),
       HasBranchIntoScope(false),
       HasIndirectGoto(false),
       HasDroppedStmt(false),
       HasOMPDeclareReductionCombiner(false),
       HasFallthroughStmt(false),
+      HasPotentialAvailabilityViolations(false),
       ObjCShouldCallSuper(false),
       ObjCIsDesignatedInit(false),
       ObjCWarnForNoDesignatedInitChain(false),
       ObjCIsSecondaryInit(false),
       ObjCWarnForNoInitDelegation(false),
       ErrorTrap(Diag) { }
 
   virtual ~FunctionScopeInfo();

cfe/trunk/include/clang/Sema/Sema.h

void EmitAvailabilityWarning(AvailabilityResult AR, NamedDecl *D,
                                StringRef Message, SourceLocation Loc,
                                const ObjCInterfaceDecl *UnknownObjCClass,
                                const ObjCPropertyDecl *ObjCProperty,
                                bool ObjCPropertyAccess);
 
   bool makeUnavailableInSystemHeader(SourceLocation loc,
                                      UnavailableAttr::ImplicitReason reason);
 
+  /// \brief Issue any -Wunguarded-availability warnings in \c FD
+  void DiagnoseUnguardedAvailabilityViolations(Decl *FD);
+
   //===--------------------------------------------------------------------===//
   // Expression Parsing Callbacks: SemaExpr.cpp.
 
   bool CanUseDecl(NamedDecl *D, bool TreatUnavailableAsInvalid);
   bool DiagnoseUseOfDecl(NamedDecl *D, SourceLocation Loc,
                          const ObjCInterfaceDecl *UnknownObjCClass=nullptr,
                          bool ObjCPropertyAccess=false);
   void NoteDeletedFunction(FunctionDecl *FD);

cfe/trunk/lib/AST/Stmt.cpp

if (!V) {
     return;
   }
 
   SourceRange VarRange = V->getSourceRange();
   SubExprs[VAR] = new (C) DeclStmt(DeclGroupRef(V), VarRange.getBegin(),
                                    VarRange.getEnd());
 }
 
+bool IfStmt::isObjCAvailabilityCheck() const {
+  return isa<ObjCAvailabilityCheckExpr>(SubExprs[COND]);
+}
+
 ForStmt::ForStmt(const ASTContext &C, Stmt *Init, Expr *Cond, VarDecl *condVar,
                  Expr *Inc, Stmt *Body, SourceLocation FL, SourceLocation LP,
                  SourceLocation RP)
   : Stmt(ForStmtClass), ForLoc(FL), LParenLoc(LP), RParenLoc(RP)
 {
   SubExprs[INIT] = Init;
   setConditionVariable(C, condVar);
   SubExprs[COND] = Cond;

cfe/trunk/lib/Sema/JumpDiagnostics.cpp

case Stmt::GotoStmtClass:
     // Remember both what scope a goto is in as well as the fact that we have
     // it.  This makes the second scan not have to walk the AST again.
     LabelAndGotoScopes[S] = ParentScope;
     Jumps.push_back(S);
     break;
 
   case Stmt::IfStmtClass: {
     IfStmt *IS = cast<IfStmt>(S);
-    if (!IS->isConstexpr())
+    if (!(IS->isConstexpr() || IS->isObjCAvailabilityCheck()))
       break;
 
+    unsigned Diag = IS->isConstexpr() ? diag::note_protected_by_constexpr_if
+                                      : diag::note_protected_by_if_available;
+
     if (VarDecl *Var = IS->getConditionVariable())
       BuildScopeInformation(Var, ParentScope);
 
     // Cannot jump into the middle of the condition.
     unsigned NewParentScope = Scopes.size();
-    Scopes.push_back(GotoScope(ParentScope,
-                               diag::note_protected_by_constexpr_if, 0,
-                               IS->getLocStart()));
+    Scopes.push_back(GotoScope(ParentScope, Diag, 0, IS->getLocStart()));
     BuildScopeInformation(IS->getCond(), NewParentScope);
 
     // Jumps into either arm of an 'if constexpr' are not allowed.
     NewParentScope = Scopes.size();
-    Scopes.push_back(GotoScope(ParentScope,
-                               diag::note_protected_by_constexpr_if, 0,
-                               IS->getLocStart()));
+    Scopes.push_back(GotoScope(ParentScope, Diag, 0, IS->getLocStart()));
     BuildScopeInformation(IS->getThen(), NewParentScope);
     if (Stmt *Else = IS->getElse()) {
       NewParentScope = Scopes.size();
-      Scopes.push_back(GotoScope(ParentScope,
-                                 diag::note_protected_by_constexpr_if, 0,
-                                 IS->getLocStart()));
+      Scopes.push_back(GotoScope(ParentScope, Diag, 0, IS->getLocStart()));
       BuildScopeInformation(Else, NewParentScope);
     }
     return;
   }
 
   case Stmt::CXXTryStmtClass: {
     CXXTryStmt *TS = cast<CXXTryStmt>(S);
     {

cfe/trunk/lib/Sema/ScopeInfo.cpp

 using namespace sema;
 
 void FunctionScopeInfo::Clear() {
   HasBranchProtectedScope = false;
   HasBranchIntoScope = false;
   HasIndirectGoto = false;
   HasDroppedStmt = false;
   HasOMPDeclareReductionCombiner = false;
+  HasPotentialAvailabilityViolations = false;
   ObjCShouldCallSuper = false;
   ObjCIsDesignatedInit = false;
   ObjCWarnForNoDesignatedInitChain = false;
   ObjCIsSecondaryInit = false;
   ObjCWarnForNoInitDelegation = false;
   FirstReturnLoc = SourceLocation();
   FirstCXXTryLoc = SourceLocation();
   FirstSEHTryLoc = SourceLocation();

cfe/trunk/lib/Sema/SemaDecl.cpp

if (getCurFunction()->ObjCWarnForNoInitDelegation) {
         Diag(MD->getLocation(),
              diag::warn_objc_secondary_init_missing_init_call);
       getCurFunction()->ObjCWarnForNoInitDelegation = false;
     }
   } else {
     return nullptr;
   }
 
+  if (Body && getCurFunction()->HasPotentialAvailabilityViolations)
+    DiagnoseUnguardedAvailabilityViolations(dcl);
+
   assert(!getCurFunction()->ObjCShouldCallSuper &&
          "This should only be set for ObjC methods, which should have been "
          "handled in the block above.");
 
   // Verify and clean out per-function state.
   if (Body && (!FD || !FD->isDefaulted())) {
     // C++ constructors that have function-try-blocks can't have return
     // statements in the handlers of that block. (C++ [except.handle]p14)

cfe/trunk/lib/Sema/SemaDeclAttr.cpp

 #include "clang/AST/ASTMutationListener.h"
 #include "clang/AST/CXXInheritance.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/Expr.h"
 #include "clang/AST/ExprCXX.h"
 #include "clang/AST/Mangle.h"
+#include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Sema/DeclSpec.h"
 #include "clang/Sema/DelayedDiagnostic.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
if (auto attr = D->getAttr<UnavailableAttr>()) {
           diag_available_here = diag::note_arc_field_with_ownership;
           break;
         }
       }
     }
     break;
 
   case AR_NotYetIntroduced:
+    assert(!S.getCurFunctionOrMethodDecl() &&
+           "Function-level partial availablity should not be diagnosed here!");
+
     diag = diag::warn_partial_availability;
     diag_message = diag::warn_partial_message;
     diag_fwdclass_message = diag::warn_partial_fwdclass_message;
     property_note_select = /* partial */ 2;
     available_here_select_kind = /* partial */ 3;
     break;
 
   case AR_Available:
VersionTuple Sema::getVersionForDecl(const Decl *D) const {
   if (Interface) {
     if (const auto *AA = getAttrForPlatform(getASTContext(), Interface))
       if (AA->getIntroduced() > DeclVersion)
         DeclVersion = AA->getIntroduced();
   }
 
   return std::max(DeclVersion, Context.getTargetInfo().getPlatformMinVersion());
 }
+
+namespace {
+
+/// \brief This class implements -Wunguarded-availability.
+///
+/// This is done with a traversal of the AST of a function that makes reference
+/// to a partially available declaration. Whenever we encounter an \c if of the
+/// form: \c if(@available(...)), we use the version from the condition to visit
+/// the then statement.
+class DiagnoseUnguardedAvailability
+    : public RecursiveASTVisitor<DiagnoseUnguardedAvailability> {
+  typedef RecursiveASTVisitor<DiagnoseUnguardedAvailability> Base;
+
+  Sema &SemaRef;
+
+  /// Stack of potentially nested 'if (@available(...))'s.
+  SmallVector<VersionTuple, 8> AvailabilityStack;
+
+  void DiagnoseDeclAvailability(NamedDecl *D, SourceRange Range);
+
+public:
+  DiagnoseUnguardedAvailability(Sema &SemaRef, VersionTuple BaseVersion)
+      : SemaRef(SemaRef) {
+    AvailabilityStack.push_back(BaseVersion);
+  }
+
+  void IssueDiagnostics(Stmt *S) { TraverseStmt(S); }
+
+  bool TraverseIfStmt(IfStmt *If);
+
+  bool VisitObjCMessageExpr(ObjCMessageExpr *Msg) {
+    if (ObjCMethodDecl *D = Msg->getMethodDecl())
+      DiagnoseDeclAvailability(
+          D, SourceRange(Msg->getSelectorStartLoc(), Msg->getLocEnd()));
+    return true;
+  }
+
+  bool VisitDeclRefExpr(DeclRefExpr *DRE) {
+    DiagnoseDeclAvailability(DRE->getDecl(),
+                             SourceRange(DRE->getLocStart(), DRE->getLocEnd()));
+    return true;
+  }
+
+  bool VisitMemberExpr(MemberExpr *ME) {
+    DiagnoseDeclAvailability(ME->getMemberDecl(),
+                             SourceRange(ME->getLocStart(), ME->getLocEnd()));
+    return true;
+  }
+
+  bool VisitTypeLoc(TypeLoc Ty);
+};
+
+void DiagnoseUnguardedAvailability::DiagnoseDeclAvailability(
+    NamedDecl *D, SourceRange Range) {
+
+  VersionTuple ContextVersion = AvailabilityStack.back();
+  if (AvailabilityResult Result = SemaRef.ShouldDiagnoseAvailabilityOfDecl(
+          D, ContextVersion, nullptr)) {
+    // All other diagnostic kinds have already been handled in
+    // DiagnoseAvailabilityOfDecl.
+    if (Result != AR_NotYetIntroduced)
+      return;
+
+    const AvailabilityAttr *AA = getAttrForPlatform(SemaRef.getASTContext(), D);
+    VersionTuple Introduced = AA->getIntroduced();
+
+    SemaRef.Diag(Range.getBegin(), diag::warn_unguarded_availability)
+        << Range << D
+        << AvailabilityAttr::getPrettyPlatformName(
+               SemaRef.getASTContext().getTargetInfo().getPlatformName())
+        << Introduced.getAsString();
+
+    SemaRef.Diag(D->getLocation(), diag::note_availability_specified_here)
+        << D << /* partial */ 3;
+
+    // FIXME: Replace this with a fixit diagnostic.
+    SemaRef.Diag(Range.getBegin(), diag::note_unguarded_available_silence)
+        << Range << D;
+  }
+}
+
+bool DiagnoseUnguardedAvailability::VisitTypeLoc(TypeLoc Ty) {
+  const Type *TyPtr = Ty.getTypePtr();
+  SourceRange Range{Ty.getBeginLoc(), Ty.getEndLoc()};
+
+  if (const TagType *TT = dyn_cast<TagType>(TyPtr)) {
+    TagDecl *TD = TT->getDecl();
+    DiagnoseDeclAvailability(TD, Range);
+
+  } else if (const TypedefType *TD = dyn_cast<TypedefType>(TyPtr)) {
+    TypedefNameDecl *D = TD->getDecl();
+    DiagnoseDeclAvailability(D, Range);
+
+  } else if (const auto *ObjCO = dyn_cast<ObjCObjectType>(TyPtr)) {
+    if (NamedDecl *D = ObjCO->getInterface())
+      DiagnoseDeclAvailability(D, Range);
+  }
+
+  return true;
+}
+
+bool DiagnoseUnguardedAvailability::TraverseIfStmt(IfStmt *If) {
+  VersionTuple CondVersion;
+  if (auto *E = dyn_cast<ObjCAvailabilityCheckExpr>(If->getCond())) {
+    CondVersion = E->getVersion();
+
+    // If we're using the '*' case here or if this check is redundant, then we
+    // use the enclosing version to check both branches.
+    if (CondVersion.empty() || CondVersion <= AvailabilityStack.back())
+      return Base::TraverseStmt(If->getThen()) &&
+             Base::TraverseStmt(If->getElse());
+  } else {
+    // This isn't an availability checking 'if', we can just continue.
+    return Base::TraverseIfStmt(If);
+  }
+
+  AvailabilityStack.push_back(CondVersion);
+  bool ShouldContinue = TraverseStmt(If->getThen());
+  AvailabilityStack.pop_back();
+
+  return ShouldContinue && TraverseStmt(If->getElse());
+}
+
+} // end anonymous namespace
+
+void Sema::DiagnoseUnguardedAvailabilityViolations(Decl *D) {
+  Stmt *Body = nullptr;
+
+  if (auto *FD = D->getAsFunction()) {
+    // FIXME: We only examine the pattern decl for availability violations now,
+    // but we should also examine instantiated templates.
+    if (FD->isTemplateInstantiation())
+      return;
+
+    Body = FD->getBody();
+  } else if (auto *MD = dyn_cast<ObjCMethodDecl>(D))
+    Body = MD->getBody();
+
+  assert(Body && "Need a body here!");
+
+  VersionTuple BaseVersion = getVersionForDecl(D);
+  DiagnoseUnguardedAvailability(*this, BaseVersion).IssueDiagnostics(Body);
+}

cfe/trunk/lib/Sema/SemaExpr.cpp

if (const DeclContext *DC = S.getCurObjCLexicalContext())
     ContextVersion = S.getVersionForDecl(cast<Decl>(DC));
 
   std::string Message;
   // See if this declaration is unavailable, deprecated, or partial in the
   // current context.
   if (AvailabilityResult Result =
           S.ShouldDiagnoseAvailabilityOfDecl(D, ContextVersion, &Message)) {
 
+    if (Result == AR_NotYetIntroduced && S.getCurFunctionOrMethodDecl()) {
+      S.getEnclosingFunction()->HasPotentialAvailabilityViolations = true;
+      return;
+    }
+
     const ObjCPropertyDecl *ObjCPDecl = nullptr;
     if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
       if (const ObjCPropertyDecl *PD = MD->findPropertyDecl()) {
         AvailabilityResult PDeclResult =
             PD->getAvailability(nullptr, ContextVersion);
         if (PDeclResult == Result)
           ObjCPDecl = PD;
       }
ExprResult Sema::ActOnObjCAvailabilityCheckExpr(
   auto Spec = std::find_if(AvailSpecs.begin(), AvailSpecs.end(),
                            [&](const AvailabilitySpec &Spec) {
                              return Spec.getPlatform() == Platform;
                            });
 
   VersionTuple Version;
   if (Spec != AvailSpecs.end())
     Version = Spec->getVersion();
-  else
-    // This is the '*' case in @available. We should diagnose this; the
-    // programmer should explicitly account for this case if they target this
-    // platform.
-    Diag(AtLoc, diag::warn_available_using_star_case) << RParen << Platform;
 
   return new (Context)
       ObjCAvailabilityCheckExpr(Version, AtLoc, RParen, Context.BoolTy);
 }

cfe/trunk/lib/Sema/SemaStmt.cpp

 
 StmtResult Sema::BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
                              Stmt *InitStmt, ConditionResult Cond,
                              Stmt *thenStmt, SourceLocation ElseLoc,
                              Stmt *elseStmt) {
   if (Cond.isInvalid())
     return StmtError();
 
-  if (IsConstexpr)
+  if (IsConstexpr || isa<ObjCAvailabilityCheckExpr>(Cond.get().second))
     getCurFunction()->setHasBranchProtectedScope();
 
   DiagnoseUnusedExprResult(thenStmt);
   DiagnoseUnusedExprResult(elseStmt);
 
   return new (Context)
       IfStmt(Context, IfLoc, IsConstexpr, InitStmt, Cond.get().first,
              Cond.get().second, thenStmt, ElseLoc, elseStmt);

cfe/trunk/test/Parser/objc-available.m

void f() {
 
   (void)@available(macos 10.11); // expected-error{{must handle potential future platforms with '*'}}
   (void)@available(macos 10.11, macos 10.11, *); // expected-error{{version for 'macos' already specified}}
 
   (void)@available(erik_os 10.11, *); // expected-error{{unrecognized platform name erik_os}}
 
   (void)@available(erik_os 10.10, hat_os 1.0, *); // expected-error 2 {{unrecognized platform name}}
 
-  (void)@available(ios 8, *); // expected-warning{{using '*' case here, platform macos is not accounted for}}
-
   (void)@available(); // expected-error{{expected a platform name here}}
   (void)@available(macos 10.10,); // expected-error{{expected a platform name here}}
   (void)@available(macos); // expected-error{{expected a version}}
   (void)@available; // expected-error{{expected '('}}
 }

cfe/trunk/test/Sema/attr-availability.c

enum __attribute__((availability(macosx,introduced=10.8))) PartialEnum {
   kPartialEnumConstant,
 };
 
 void test_10095131() {
   ATSFontGetName("Hello"); // expected-warning {{'ATSFontGetName' is deprecated: first deprecated in macOS 9.0 - use CTFontCopyFullName}}
   ATSFontGetPostScriptName(100); // expected-error {{'ATSFontGetPostScriptName' is unavailable: obsoleted in macOS 9.0 - use ATSFontGetFullPostScriptName}}
 
 #if defined(WARN_PARTIAL)
-  // expected-warning@+2 {{is partial: introduced in macOS 10.8}} expected-note@+2 {{explicitly redeclare 'PartiallyAvailable' to silence this warning}}
+  // expected-warning@+2 {{is only available on macOS 10.8 or newer}} expected-note@+2 {{enclose 'PartiallyAvailable' in an @available check to silence this warning}}
 #endif
   PartiallyAvailable();
 }
 
 extern void PartiallyAvailable() ;
 void with_redeclaration() {
   PartiallyAvailable();  // Don't warn.
 

cfe/trunk/test/SemaObjC/attr-availability.m

 
 void f(A *a, B *b) {
   [a method]; // expected-warning{{'method' is deprecated: first deprecated in macOS 10.2}}
   [b method]; // no-warning
   [a proto_method]; // expected-warning{{'proto_method' is deprecated: first deprecated in macOS 10.2}}
   [b proto_method]; // expected-warning{{'proto_method' is deprecated: first deprecated in macOS 10.2}}
 
 #if defined(WARN_PARTIAL)
-  // expected-warning@+2 {{'partialMethod' is partial: introduced in macOS 10.8}} expected-note@+2 {{explicitly redeclare 'partialMethod' to silence this warning}}
+  // expected-warning@+2 {{'partialMethod' is only available on macOS 10.8 or newer}} expected-note@+2 {{enclose 'partialMethod' in an @available check to silence this warning}}
 #endif
   [a partialMethod];
   [b partialMethod];  // no warning
 #if defined(WARN_PARTIAL)
-  // expected-warning@+2 {{'partial_proto_method' is partial: introduced in macOS 10.8}} expected-note@+2 {{explicitly redeclare 'partial_proto_method' to silence this warning}}
+  // expected-warning@+2 {{'partial_proto_method' is only available on macOS 10.8 or newer}} expected-note@+2 {{enclose 'partial_proto_method' in an @available check to silence this warning}}
 #endif
   [a partial_proto_method];
 #if defined(WARN_PARTIAL)
-  // expected-warning@+2 {{'partial_proto_method' is partial: introduced in macOS 10.8}} expected-note@+2 {{explicitly redeclare 'partial_proto_method' to silence this warning}}
+  // expected-warning@+2 {{'partial_proto_method' is only available on macOS 10.8 or newer}} expected-note@+2 {{enclose 'partial_proto_method' in an @available check to silence this warning}}
 #endif
   [b partial_proto_method];
 }
 
 @interface A (NewAPI)
 - (void)partialMethod;
 - (void)partial_proto_method;
 @end

 + (void)ipartialMethod1;
 + (void)ppartialMethod;
 @end
 
 void partialfun(PartialI* a) {
   [a partialMethod]; // no warning
   [a ipartialMethod1]; // no warning
 #if defined(WARN_PARTIAL)
-  // expected-warning@+2 {{'ipartialMethod2' is partial: introduced in macOS 10.8}} expected-note@+2 {{explicitly redeclare 'ipartialMethod2' to silence this warning}}
+  // expected-warning@+2 {{'ipartialMethod2' is only available on macOS 10.8 or newer}} expected-note@+2 {{enclose 'ipartialMethod2' in an @available check to silence this warning}}
 #endif
   [a ipartialMethod2];
   [a ppartialMethod]; // no warning
   [PartialI partialMethod]; // no warning
   [PartialI ipartialMethod1]; // no warning
 #if defined(WARN_PARTIAL)
-  // expected-warning@+2 {{'ipartialMethod2' is partial: introduced in macOS 10.8}} expected-note@+2 {{explicitly redeclare 'ipartialMethod2' to silence this warning}}
+  // expected-warning@+2 {{'ipartialMethod2' is only available on macOS 10.8 or newer}} expected-note@+2 {{enclose 'ipartialMethod2' in an @available check to silence this warning}}
 #endif
   [PartialI ipartialMethod2];
   [PartialI ppartialMethod]; // no warning
 }
 
 #if defined(WARN_PARTIAL)
   // expected-note@+2 {{'PartialI2' has been explicitly marked partial here}}
 #endif

 }
 
 __attribute__((objc_root_class))
 @interface LookupAvailabilityBase
 -(void) method1;
 @end
 
 @implementation LookupAvailabilityBase
--(void)method1 { fn_10_7(); } // expected-warning{{partial}} expected-note{{explicitly redeclare}}
+-(void)method1 { fn_10_7(); } // expected-warning{{only available on macOS 10.7}} expected-note{{@available}}
 @end
 
 __attribute__((availability(macosx, introduced=10.7)))
 @interface LookupAvailability : LookupAvailabilityBase
 - (void)method2;
 - (void)method3;
 - (void)method4 __attribute__((availability(macosx, introduced=10.8)));
 @end
 
 @implementation LookupAvailability
 -(void)method2 { fn_10_7(); }
--(void)method3 { fn_10_8(); } // expected-warning{{partial}} expected-note{{explicitly redeclare}}
+-(void)method3 { fn_10_8(); } // expected-warning{{only available on macOS 10.8}} expected-note{{@available}}
 -(void)method4 { fn_10_8(); }
 @end
 
 int old_func() __attribute__((availability(macos, introduced=10.4))) {
   fn_10_5();
 }
 
 #endif

cfe/trunk/test/SemaObjC/property-deprecated-warning.m

 // RUN: %clang_cc1  -fsyntax-only -triple thumbv6-apple-ios3.0 -verify -Wno-objc-root-class %s
 // RUN: %clang_cc1 -D WARN_PARTIAL -Wpartial-availability -fsyntax-only -triple thumbv6-apple-ios3.0 -verify -Wno-objc-root-class %s
 // RUN: %clang_cc1 -x objective-c++ -fsyntax-only -triple thumbv6-apple-ios3.0 -verify -Wno-objc-root-class %s
 // rdar://12324295
 
 typedef signed char BOOL;
 
 @protocol P
 @property(nonatomic,assign) id ptarget __attribute__((availability(ios,introduced=2.0,deprecated=3.0))); // expected-note {{property 'ptarget' is declared deprecated here}} expected-note {{'ptarget' has been explicitly marked deprecated here}}
 
 #if defined(WARN_PARTIAL)
-// expected-note@+2 {{property 'partialPtarget' is declared partial here}} expected-note@+2 {{'partialPtarget' has been explicitly marked partial here}}
+// expected-note@+2 {{'partialPtarget' has been explicitly marked partial here}}
 #endif
 @property(nonatomic,assign) id partialPtarget __attribute__((availability(ios,introduced=5.0)));
 @end
 
 @protocol P1<P>
 - (void)setPtarget:(id)arg;
 - (void)setPartialPtarget:(id)arg;
 @end
 
 
 @interface UITableViewCell<P1>
 @property(nonatomic,assign) id target __attribute__((availability(ios,introduced=2.0,deprecated=3.0))); // expected-note {{property 'target' is declared deprecated here}} expected-note {{'setTarget:' has been explicitly marked deprecated here}}
 
 #if defined(WARN_PARTIAL)
-// expected-note@+2 {{property 'partialTarget' is declared partial here}} expected-note@+2 {{'setPartialTarget:' has been explicitly marked partial here}}
+// expected-note@+2 {{'setPartialTarget:' has been explicitly marked partial here}}
 #endif
 @property(nonatomic,assign) id partialTarget __attribute__((availability(ios,introduced=5.0)));
 @end
 
 @interface PSTableCell : UITableViewCell
  - (void)setTarget:(id)target;
  - (void)setPartialTarget:(id)target;
 @end
 
 @interface UITableViewCell(UIDeprecated)
 @property(nonatomic,assign) id dep_target  __attribute__((availability(ios,introduced=2.0,deprecated=3.0))); // expected-note 2 {{'dep_target' has been explicitly marked deprecated here}} \
                                                                                     // expected-note 4 {{property 'dep_target' is declared deprecated here}} \
                                                                                     // expected-note 2 {{'setDep_target:' has been explicitly marked deprecated here}}
 
 #if defined(WARN_PARTIAL)
-// expected-note@+2 4 {{property 'partial_dep_target' is declared partial here}} expected-note@+2 2 {{'partial_dep_target' has been explicitly marked partial here}} expected-note@+2 2 {{'setPartial_dep_target:' has been explicitly marked partial here}}
+// expected-note@+2 2 {{'partial_dep_target' has been explicitly marked partial here}} expected-note@+2 2 {{'setPartial_dep_target:' has been explicitly marked partial here}}
 #endif
 @property(nonatomic,assign) id partial_dep_target  __attribute__((availability(ios,introduced=5.0)));
 @end
 
 @implementation PSTableCell
 - (void)setTarget:(id)target {};
 - (void)setPartialTarget:(id)target {};
 - (void)setPtarget:(id)val {};
 - (void) Meth {
   [self setTarget: (id)0]; // no-warning
   [self setDep_target: [self dep_target]]; // expected-warning {{'dep_target' is deprecated: first deprecated in iOS 3.0}} \
                                            // expected-warning {{'setDep_target:' is deprecated: first deprecated in iOS 3.0}}
              
   [self setPtarget: (id)0]; // no-warning
   [self setPartialTarget: (id)0]; // no-warning
 #if defined(WARN_PARTIAL)
-  // expected-warning@+2 {{'partial_dep_target' is partial: introduced in iOS 5.0}} expected-warning@+2 {{'setPartial_dep_target:' is partial: introduced in iOS 5.0}} expected-note@+2 {{explicitly redeclare 'partial_dep_target' to silence this warning}} expected-note@+2 {{explicitly redeclare 'setPartial_dep_target:' to silence this warning}}
+  // expected-warning@+2 {{'partial_dep_target' is only available on iOS 5.0 or newer}} expected-warning@+2 {{'setPartial_dep_target:' is only available on iOS 5.0 or newer}} expected-note@+2 {{enclose 'partial_dep_target' in an @available check to silence this warning}} expected-note@+2 {{enclose 'setPartial_dep_target:' in an @available check to silence this warning}}
 #endif
   [self setPartial_dep_target: [self partial_dep_target]];
 
   [self setPartialPtarget: (id)0]; // no-warning
 }
 @end
 
 @implementation UITableViewCell
 @synthesize target;
 @synthesize partialTarget;
 @synthesize ptarget;
 @synthesize partialPtarget;
 - (void)setPtarget:(id)val {};
 - (void)setPartialPtarget:(id)val {};
 - (void)setTarget:(id)target {};
 - (void)setPartialTarget:(id)target {};
 - (void) Meth {
   [self setTarget: (id)0]; // expected-warning {{'setTarget:' is deprecated: first deprecated in iOS 3.0}}
   [self setDep_target: [self dep_target]]; // expected-warning {{'dep_target' is deprecated: first deprecated in iOS 3.0}} \
                                            // expected-warning {{'setDep_target:' is deprecated: first deprecated in iOS 3.0}}
 
   [self setPtarget: (id)0]; // no-warning
 
 #if defined(WARN_PARTIAL)
-  // expected-warning@+2 {{'setPartialTarget:' is partial: introduced in iOS 5.0}} expected-note@+2 {{explicitly redeclare 'setPartialTarget:' to silence this warning}}
+  // expected-warning@+2 {{'setPartialTarget:' is only available on iOS 5.0 or newer}} expected-note@+2 {{enclose 'setPartialTarget:' in an @available check to silence this warning}}
 #endif
   [self setPartialTarget: (id)0];
 #if defined(WARN_PARTIAL)
-  // expected-warning@+2 {{'partial_dep_target' is partial: introduced in iOS 5.0}} expected-warning@+2 {{'setPartial_dep_target:' is partial: introduced in iOS 5.0}} expected-note@+2 {{explicitly redeclare 'partial_dep_target' to silence this warning}} expected-note@+2 {{explicitly redeclare 'setPartial_dep_target:' to silence this warning}}
+  // expected-warning@+2 {{'partial_dep_target' is only available on iOS 5.0 or newer}} expected-warning@+2 {{'setPartial_dep_target:' is only available on iOS 5.0 or newer}} expected-note@+2 {{enclose 'partial_dep_target' in an @available check to silence this warning}} expected-note@+2 {{enclose 'setPartial_dep_target:' in an @available check to silence this warning}}
 #endif
   [self setPartial_dep_target: [self partial_dep_target]];
   [self setPartialPtarget: (id)0]; // no-warning
 }
 @end
 
 
 @interface CustomAccessorNames
 @property(getter=isEnabled,assign) BOOL enabled __attribute__((availability(ios,introduced=2.0,deprecated=3.0))); // expected-note {{'isEnabled' has been explicitly marked deprecated here}} expected-note {{property 'enabled' is declared deprecated here}}
 
 @property(setter=setNewDelegate:,assign) id delegate __attribute__((availability(ios,introduced=2.0,deprecated=3.0))); // expected-note {{'setNewDelegate:' has been explicitly marked deprecated here}} expected-note {{property 'delegate' is declared deprecated here}}
 
 #if defined(WARN_PARTIAL)
-// expected-note@+2 {{property 'partialEnabled' is declared partial here}} expected-note@+2 {{'partialIsEnabled' has been explicitly marked partial here}}
+// expected-note@+2 {{'partialIsEnabled' has been explicitly marked partial here}}
 #endif
 @property(getter=partialIsEnabled,assign) BOOL partialEnabled __attribute__((availability(ios,introduced=5.0)));
 
 #if defined(WARN_PARTIAL)
-// expected-note@+2 {{property 'partialDelegate' is declared partial here}} expected-note@+2 {{'partialSetNewDelegate:' has been explicitly marked partial here}}
+// expected-note@+2 {{'partialSetNewDelegate:' has been explicitly marked partial here}}
 #endif
 @property(setter=partialSetNewDelegate:,assign) id partialDelegate __attribute__((availability(ios,introduced=5.0)));
 @end
 
 void testCustomAccessorNames(CustomAccessorNames *obj) {
   if ([obj isEnabled]) // expected-warning {{'isEnabled' is deprecated: first deprecated in iOS 3.0}}
     [obj setNewDelegate:0]; // expected-warning {{'setNewDelegate:' is deprecated: first deprecated in iOS 3.0}}
 
 #if defined(WARN_PARTIAL)
-// expected-warning@+2 {{'partialIsEnabled' is partial: introduced in iOS 5.0}} expected-warning@+3 {{'partialSetNewDelegate:' is partial: introduced in iOS 5.0}} expected-note@+2 {{explicitly redeclare 'partialIsEnabled' to silence this warning}} expected-note@+3 {{explicitly redeclare 'partialSetNewDelegate:' to silence this warning}}
+  // expected-warning@+2 {{'partialIsEnabled' is only available on iOS 5.0 or newer}} expected-warning@+3 {{'partialSetNewDelegate:' is only available on iOS 5.0 or newer}} expected-note@+2 {{enclose 'partialIsEnabled' in an @available check to silence this warning}} expected-note@+3 {{enclose 'partialSetNewDelegate:' in an @available check to silence this warning}}
 #endif
   if ([obj partialIsEnabled])
     [obj partialSetNewDelegate:0];
 }
 
 
 @interface ProtocolInCategory
 @end
 
 @interface ProtocolInCategory (TheCategory) <P1>
 - (id)ptarget;
 - (id)partialPtarget;
 @end
 
 id useDeprecatedProperty(ProtocolInCategory *obj, id<P> obj2, int flag) {
   if (flag)
     return [obj ptarget];  // no-warning
   return [obj2 ptarget];   // expected-warning {{'ptarget' is deprecated: first deprecated in iOS 3.0}}
 
   if (flag)
     return [obj partialPtarget];  // no-warning
 #if defined(WARN_PARTIAL)
-// expected-warning@+2 {{'partialPtarget' is partial: introduced in iOS 5.0}} expected-note@+2 {{explicitly redeclare 'partialPtarget' to silence this warning}}
+// expected-warning@+2 {{'partialPtarget' is only available on iOS 5.0 or newer}} expected-note@+2 {{enclose 'partialPtarget' in an @available check to silence this warning}}
 #endif
   return [obj2 partialPtarget];
 }
 
 // rdar://15951801
 @interface Foo
 {
   int _x;

cfe/trunk/test/SemaObjC/unguarded-availability.m

+// RUN: %clang_cc1 -triple x86_64-apple-macosx-10.9 -Wunguarded-availability -fblocks -fsyntax-only -verify %s
+// RUN: %clang_cc1 -xobjective-c++ -DOBJCPP -triple x86_64-apple-macosx-10.9 -Wunguarded-availability -fblocks -fsyntax-only -verify %s
+
+#define AVAILABLE_10_0  __attribute__((availability(macos, introduced = 10.0)))
+#define AVAILABLE_10_11 __attribute__((availability(macos, introduced = 10.11)))
+#define AVAILABLE_10_12 __attribute__((availability(macos, introduced = 10.12)))
+
+int func_10_11() AVAILABLE_10_11; // expected-note 4 {{'func_10_11' has been explicitly marked partial here}}
+
+#ifdef OBJCPP
+// expected-note@+2 {{marked partial here}}
+#endif
+int func_10_12() AVAILABLE_10_12; // expected-note 5 {{'func_10_12' has been explicitly marked partial here}}
+
+int func_10_0() AVAILABLE_10_0;
+
+void use_func() {
+  func_10_11(); // expected-warning{{'func_10_11' is only available on macOS 10.11 or newer}} expected-note{{enclose 'func_10_11' in an @available check to silence this warning}}
+
+  if (@available(macos 10.11, *))
+    func_10_11();
+  else
+    func_10_11(); // expected-warning{{'func_10_11' is only available on macOS 10.11 or newer}} expected-note{{enclose 'func_10_11' in an @available check to silence this warning}}
+}
+
+void defn_10_11() AVAILABLE_10_11;
+
+void defn_10_11() {
+  func_10_11();
+}
+
+void nested_ifs() {
+  if (@available(macos 10.12, *)) {
+    if (@available(macos 10.10, *)) {
+      func_10_12();
+    } else {
+      func_10_12();
+    }
+  } else {
+    func_10_12(); // expected-warning{{'func_10_12' is only available on macOS 10.12 or newer}} expected-note{{enclose 'func_10_12' in an @available check to silence this warning}}
+  }
+}
+
+void star_case() {
+  if (@available(ios 9, *)) {
+    func_10_11(); // expected-warning{{'func_10_11' is only available on macOS 10.11 or newer}} expected-note{{enclose 'func_10_11' in an @available check to silence this warning}}
+    func_10_0();
+  } else
+    func_10_11(); // expected-warning{{'func_10_11' is only available on macOS 10.11 or newer}} expected-note{{enclose 'func_10_11' in an @available check to silence this warning}}
+
+  if (@available(macos 10.11, *)) {
+    if (@available(ios 8, *)) {
+      func_10_11();
+      func_10_12(); // expected-warning{{'func_10_12' is only available on macOS 10.12 or newer}} expected-note{{enclose}}
+    } else {
+      func_10_11();
+      func_10_12(); // expected-warning{{'func_10_12' is only available on macOS 10.12 or newer}} expected-note{{enclose}}
+    }
+  }
+}
+
+typedef int int_10_11 AVAILABLE_10_11; // expected-note {{'int_10_11' has been explicitly marked partial here}}
+#ifdef OBJCPP
+// expected-note@+2 {{marked partial here}}
+#endif
+typedef int int_10_12 AVAILABLE_10_12; // expected-note 3 {{'int_10_12' has been explicitly marked partial here}}
+
+void use_typedef() {
+  int_10_11 x; // expected-warning{{'int_10_11' is only available on macOS 10.11 or newer}} expected-note{{enclose 'int_10_11' in an @available check to silence this warning}}
+}
+
+__attribute__((objc_root_class))
+AVAILABLE_10_11 @interface Class_10_11 {
+  int_10_11 foo;
+  int_10_12 bar; // expected-warning {{'int_10_12' is partial: introduced in macOS 10.12}} expected-note{{redeclare}}
+}
+- (void)method1;
+- (void)method2;
+@end
+
+@implementation Class_10_11
+- (void) method1 {
+  func_10_11();
+  func_10_12(); // expected-warning{{'func_10_12' is only available on macOS 10.12 or newer}} expected-note{{enclose 'func_10_12' in an @available check to silence this warning}}
+}
+
+- (void)method2 AVAILABLE_10_12 {
+  func_10_12();
+}
+
+@end
+
+int protected_scope() {
+  if (@available(macos 10.20, *)) { // expected-note 2 {{jump enters controlled statement of if available}}
+  label1:
+    return 0;
+  } else {
+  label2:
+    goto label1; // expected-error{{cannot jump from this goto statement to its label}}
+  }
+
+  goto label2; // expected-error{{cannot jump from this goto statement to its label}}
+}
+
+struct S {
+  int m1;
+  int m2 __attribute__((availability(macos, introduced = 10.12))); // expected-note{{marked partial here}}
+
+  struct Nested {
+    int nested_member __attribute__((availability(macos, introduced = 10.12))); // expected-note{{marked partial here}}
+  } n;
+};
+
+int test_members() {
+  struct S s;
+  (void)s.m1;
+  (void)s.m2; // expected-warning{{'m2' is only available on macOS 10.12 or newer}} expected-note{{@available}}
+
+  (void)s.n.nested_member; // expected-warning{{'nested_member' is only available on macOS 10.12 or newer}} expected-note{{@available}}
+}
+
+void test_blocks() {
+  (void) ^{
+    func_10_12(); // expected-warning{{'func_10_12' is only available on macOS 10.12 or newer}} expected-note{{@available}}
+  };
+}
+
+void test_params(int_10_12 x); // expected-warning {{'int_10_12' is partial: introduced in macOS 10.12}} expected-note{{redeclare}}
+
+// FIXME: This should be fine!
+void test_params2(int_10_12 x) AVAILABLE_10_12; // expected-warning {{'int_10_12' is partial: introduced in macOS 10.12}} expected-note{{redeclare}}
+
+#ifdef OBJCPP
+
+int f(char) AVAILABLE_10_12;
+int f(int);
+
+template <class T> int use_f() {
+  // FIXME: We should warn here!
+  return f(T());
+}
+
+int a = use_f<int>();
+int b = use_f<char>();
+
+template <class> int use_at_available() {
+  if (@available(macos 10.12, *))
+    return func_10_12();
+  else
+    return func_10_12(); // expected-warning {{'func_10_12' is only available on macOS 10.12 or newer}} expected-note{{enclose}}
+}
+
+int instantiate_template() {
+  if (@available(macos 10.12, *)) {
+    use_at_available<char>();
+  } else {
+    use_at_available<float>();
+  }
+}
+
+template <class>
+int with_availability_attr() AVAILABLE_10_11 { // expected-note 2 {{marked partial here}}
+  return 0;
+}
+
+int instantiate_with_availability_attr() {
+  if (@available(macos 10.12, *))
+    with_availability_attr<char>();
+  else
+    with_availability_attr<int>(); // expected-warning {{'with_availability_attr<int>' is only available on macOS 10.11 or newer}} expected-note {{enclose}}
+}
+
+int instantiate_availability() {
+  if (@available(macos 10.12, *))
+    with_availability_attr<int_10_12>();
+  else
+    with_availability_attr<int_10_12>(); // expected-warning{{'with_availability_attr<int>' is only available on macOS 10.11 or newer}} expected-warning{{'int_10_12' is only available on macOS 10.12 or newer}} expected-note 2 {{enclose}}
+}
+
+#endif