AST: Warn for non-existent platform versions in @available attributes.

include/swift/AST/AvailabilityDomain.h

@@ -209,6 +209,10 @@ public:
   /// version ranges.
   bool isVersioned() const;
 
+  /// Returns true if the given version is a valid version number for this
+  /// domain. It is an error to call this on an un-versioned domain.
+  bool isVersionValid(const llvm::VersionTuple &version) const;
+
   /// Returns true if availability of the domain can be refined using
   /// `@available` attributes and `if #available` queries. If not, then the
   /// domain's availability is fixed by compilation settings. For example,

include/swift/AST/DiagnosticsSema.def

@@ -6929,6 +6929,9 @@ GROUPED_ERROR(availability_suggest_platform_name,
         (Identifier, StringRef))
 WARNING(availability_unsupported_version_number, none,
         "'%0' is not a supported version number", (llvm::VersionTuple))
+WARNING(availability_invalid_version_number_for_domain, none,
+        "'%0' is not a valid version number for %1",
+        (llvm::VersionTuple, AvailabilityDomain))
 
 WARNING(attr_availability_expected_deprecated_version, none,
        "expected version number with 'deprecated' in '%0' attribute for %1",

include/swift/AST/PlatformKind.h

@@ -21,6 +21,7 @@
 #include "swift/Config.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/VersionTuple.h"
+#include "llvm/TargetParser/Triple.h"
 #include <optional>
 
 namespace swift {
@@ -91,6 +92,10 @@ PlatformKind targetVariantPlatform(const LangOptions &LangOpts);
 /// an explicit attribute for the child.
 bool inheritsAvailabilityFromPlatform(PlatformKind Child, PlatformKind Parent);
 
+/// Returns the LLVM triple OS type for the given platform, if there is one.
+std::optional<llvm::Triple::OSType>
+tripleOSTypeForPlatform(PlatformKind platform);
+
 llvm::VersionTuple canonicalizePlatformVersion(
     PlatformKind platform, const llvm::VersionTuple &version);
 

lib/AST/Availability.cpp

@@ -832,7 +832,10 @@ SemanticAvailableAttrRequest::evaluate(swift::Evaluator &evaluator,
 
   auto checkVersion = [&](std::optional<llvm::VersionTuple> version,
                           SourceRange sourceRange) {
-    if (version && !VersionRange::isValidVersion(*version)) {
+    if (!version)
+      return false;
+
+    if (!VersionRange::isValidVersion(*version)) {
       diags
           .diagnose(attrLoc, diag::availability_unsupported_version_number,
                     *version)
@@ -840,6 +843,16 @@ SemanticAvailableAttrRequest::evaluate(swift::Evaluator &evaluator,
       return true;
     }
 
+    // Warn if the version is not a valid one for the domain. For example, macOS
+    // 17 will never exist.
+    if (domain->isVersioned() && !domain->isVersionValid(*version)) {
+      diags
+          .diagnose(attrLoc,
+                    diag::availability_invalid_version_number_for_domain,
+                    *version, *domain)
+          .highlight(sourceRange);
+    }
+
     return false;
   };
 

lib/AST/AvailabilityDomain.cpp

@@ -109,6 +109,26 @@ bool AvailabilityDomain::isVersioned() const {
   }
 }
 
+bool AvailabilityDomain::isVersionValid(
+    const llvm::VersionTuple &version) const {
+  ASSERT(isVersioned());
+
+  switch (getKind()) {
+  case Kind::Universal:
+  case Kind::Embedded:
+    llvm_unreachable("unexpected domain kind");
+  case Kind::SwiftLanguage:
+  case Kind::PackageDescription:
+    return true;
+  case Kind::Platform:
+    if (auto osType = tripleOSTypeForPlatform(getPlatformKind()))
+      return llvm::Triple::isValidVersionForOS(*osType, version);
+    return true;
+  case Kind::Custom:
+    return true;
+  }
+}
+
 bool AvailabilityDomain::supportsContextRefinement() const {
   switch (getKind()) {
   case Kind::Universal:

lib/AST/PlatformKind.cpp

@@ -263,8 +263,8 @@ bool swift::inheritsAvailabilityFromPlatform(PlatformKind Child,
   return false;
 }
 
-static std::optional<llvm::Triple::OSType>
-tripleOSTypeForPlatform(PlatformKind platform) {
+std::optional<llvm::Triple::OSType>
+swift::tripleOSTypeForPlatform(PlatformKind platform) {
   switch (platform) {
   case PlatformKind::macOS:
   case PlatformKind::macOSApplicationExtension:
@@ -296,8 +296,11 @@ tripleOSTypeForPlatform(PlatformKind platform) {
 llvm::VersionTuple
 swift::canonicalizePlatformVersion(PlatformKind platform,
                                    const llvm::VersionTuple &version) {
-  if (auto osType = tripleOSTypeForPlatform(platform))
-    return llvm::Triple::getCanonicalVersionForOS(*osType, version);
+  if (auto osType = tripleOSTypeForPlatform(platform)) {
+    bool isInValidRange = llvm::Triple::isValidVersionForOS(*osType, version);
+    return llvm::Triple::getCanonicalVersionForOS(*osType, version,
+                                                  isInValidRange);
+  }
 
   return version;
 }

test/IDE/print_ast_tc_decls_canonical_versions.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -typecheck -verify %s
+// RUN: %target-swift-frontend -typecheck %s
 // RUN: %target-swift-ide-test -skip-deinit=false -print-ast-typechecked -source-filename %s -function-definitions=false -prefer-type-repr=false -print-implicit-attrs=true > %t.printed.txt
 // RUN: %FileCheck %s -check-prefix=PASS_COMMON -strict-whitespace < %t.printed.txt
 

test/Sema/availability_versions_canonical.swift

@@ -1,4 +1,8 @@
-// RUN: %target-typecheck-verify-swift -target %target-swift-5.1-abi-triple
+// RUN: %swift -typecheck %s -verify -parse-stdlib -module-name Swift -target x86_64-apple-macosx10.15 -verify-additional-prefix macos-
+// RUN: %swift -typecheck %s -verify -parse-stdlib -module-name Swift -target arm64-apple-ios13 -verify-additional-prefix ios-
+// RUN: %swift -typecheck %s -verify -parse-stdlib -module-name Swift -target arm64-apple-watchos6 -verify-additional-prefix watchos-
+// RUN: %swift -typecheck %s -verify -parse-stdlib -module-name Swift -target arm64-apple-tvos13 -verify-additional-prefix tvos-
+// RUN: %swift -typecheck %s -verify -parse-stdlib -module-name Swift -target arm64-apple-xros1 -verify-additional-prefix visionos-
 
 @available(OSX 10.16, *)
 func introducedOnMacOS10_16() { }
@@ -12,7 +16,59 @@ func introducedInVersionsMappingTo26_0() { }
 @available(macOS 26.0, iOS 26.0, watchOS 26.0, tvOS 26.0, visionOS 26.0, *)
 func introducedIn26_0() { }
 
+@available(macOS 17.0, iOS 20.0, watchOS 13.0, tvOS 20.0, visionOS 4.0, *)
+// expected-warning@-1 {{'17.0' is not a valid version number for macOS}}
+// expected-warning@-2 {{'20.0' is not a valid version number for iOS}}
+// expected-warning@-3 {{'13.0' is not a valid version number for watchOS}}
+// expected-warning@-4 {{'20.0' is not a valid version number for tvOS}}
+// expected-warning@-5 {{'4.0' is not a valid version number for visionOS}}
+func introducedInVersionsMappingTo27_0() { }
+
+@available(macOS 27.0, iOS 27.0, watchOS 27.0, tvOS 27.0, visionOS 27.0, *)
+func introducedIn27_0() { }
+
 func useUnderPoundAvailable() {
+  // expected-note@-1 * {{add '@available' attribute to enclosing global function}}
+  introducedOnMacOS10_16()
+  // expected-macos-error@-1 {{'introducedOnMacOS10_16()' is only available in macOS 11.0 or newer}}
+  // expected-macos-note@-2 {{add 'if #available' version check}}
+
+  introducedOnMacOS11_0()
+  // expected-macos-error@-1 {{'introducedOnMacOS11_0()' is only available in macOS 11.0 or newer}}
+  // expected-macos-note@-2 {{add 'if #available' version check}}
+
+  introducedInVersionsMappingTo26_0()
+  // expected-macos-error@-1 {{'introducedInVersionsMappingTo26_0()' is only available in macOS 26.0 or newer}}
+  // expected-ios-error@-2 {{'introducedInVersionsMappingTo26_0()' is only available in iOS 26.0 or newer}}
+  // expected-watchos-error@-3 {{'introducedInVersionsMappingTo26_0()' is only available in watchOS 26.0 or newer}}
+  // expected-tvos-error@-4 {{'introducedInVersionsMappingTo26_0()' is only available in tvOS 26.0 or newer}}
+  // expected-visionos-error@-5 {{'introducedInVersionsMappingTo26_0()' is only available in visionOS 26.0 or newer}}
+  // expected-note@-6 {{add 'if #available' version check}}
+
+  introducedIn26_0()
+  // expected-macos-error@-1 {{'introducedIn26_0()' is only available in macOS 26.0 or newer}}
+  // expected-ios-error@-2 {{'introducedIn26_0()' is only available in iOS 26.0 or newer}}
+  // expected-watchos-error@-3 {{'introducedIn26_0()' is only available in watchOS 26.0 or newer}}
+  // expected-tvos-error@-4 {{'introducedIn26_0()' is only available in tvOS 26.0 or newer}}
+  // expected-visionos-error@-5 {{'introducedIn26_0()' is only available in visionOS 26.0 or newer}}
+  // expected-note@-6 {{add 'if #available' version check}}
+
+  introducedInVersionsMappingTo27_0()
+  // expected-macos-error@-1 {{'introducedInVersionsMappingTo27_0()' is only available in macOS 27.0 or newer}}
+  // expected-ios-error@-2 {{'introducedInVersionsMappingTo27_0()' is only available in iOS 27.0 or newer}}
+  // expected-watchos-error@-3 {{'introducedInVersionsMappingTo27_0()' is only available in watchOS 27.0 or newer}}
+  // expected-tvos-error@-4 {{'introducedInVersionsMappingTo27_0()' is only available in tvOS 27.0 or newer}}
+  // expected-visionos-error@-5 {{'introducedInVersionsMappingTo27_0()' is only available in visionOS 27.0 or newer}}
+  // expected-note@-6 {{add 'if #available' version check}}
+
+  introducedIn27_0()
+  // expected-macos-error@-1 {{'introducedIn27_0()' is only available in macOS 27.0 or newer}}
+  // expected-ios-error@-2 {{'introducedIn27_0()' is only available in iOS 27.0 or newer}}
+  // expected-watchos-error@-3 {{'introducedIn27_0()' is only available in watchOS 27.0 or newer}}
+  // expected-tvos-error@-4 {{'introducedIn27_0()' is only available in tvOS 27.0 or newer}}
+  // expected-visionos-error@-5 {{'introducedIn27_0()' is only available in visionOS 27.0 or newer}}
+  // expected-note@-6 {{add 'if #available' version check}}
+
   if #available(OSX 10.16, *) {
     introducedOnMacOS10_16()
     introducedOnMacOS11_0()
@@ -21,5 +77,24 @@ func useUnderPoundAvailable() {
   if #available(macOS 16.0, iOS 19.0, watchOS 12.0, tvOS 19.0, visionOS 3.0, *) {
     introducedInVersionsMappingTo26_0()
     introducedIn26_0()
+    introducedInVersionsMappingTo27_0()
+    // expected-macos-error@-1 {{'introducedInVersionsMappingTo27_0()' is only available in macOS 27.0 or newer}}
+    // expected-ios-error@-2 {{'introducedInVersionsMappingTo27_0()' is only available in iOS 27.0 or newer}}
+    // expected-watchos-error@-3 {{'introducedInVersionsMappingTo27_0()' is only available in watchOS 27.0 or newer}}
+    // expected-tvos-error@-4 {{'introducedInVersionsMappingTo27_0()' is only available in tvOS 27.0 or newer}}
+    // expected-visionos-error@-5 {{'introducedInVersionsMappingTo27_0()' is only available in visionOS 27.0 or newer}}
+    // expected-note@-6 {{add 'if #available' version check}}
+    introducedIn27_0()
+    // expected-macos-error@-1 {{'introducedIn27_0()' is only available in macOS 27.0 or newer}}
+    // expected-ios-error@-2 {{'introducedIn27_0()' is only available in iOS 27.0 or newer}}
+    // expected-watchos-error@-3 {{'introducedIn27_0()' is only available in watchOS 27.0 or newer}}
+    // expected-tvos-error@-4 {{'introducedIn27_0()' is only available in tvOS 27.0 or newer}}
+    // expected-visionos-error@-5 {{'introducedIn27_0()' is only available in visionOS 27.0 or newer}}
+    // expected-note@-6 {{add 'if #available' version check}}
+  }
+
+  if #available(macOS 17.0, iOS 20.0, watchOS 13.0, tvOS 20.0, visionOS 4.0, *) {
+    introducedInVersionsMappingTo27_0()
+    introducedIn27_0()
   }
 }

test/attr/attr_availability_invalid_platform_versions.swift

@@ -0,0 +1,34 @@
+// RUN: %target-swift-frontend -typecheck -verify -parse-stdlib -module-name Swift %s
+
+@available(macOS, introduced: 17) // expected-warning {{'17' is not a valid version number for macOS}}
+@available(iOS, introduced: 20) // expected-warning {{'20' is not a valid version number for iOS}}
+@available(macCatalyst, introduced: 20) // expected-warning {{'20' is not a valid version number for Mac Catalyst}}
+@available(watchOS, introduced: 13) // expected-warning {{'13' is not a valid version number for watchOS}}
+@available(tvOS, introduced: 20) // expected-warning {{'20' is not a valid version number for tvOS}}
+@available(visionOS, introduced: 4) // expected-warning {{'4' is not a valid version number for visionOS}}
+func invalidIntroduced() { }
+
+@available(macOS, deprecated: 17) // expected-warning {{'17' is not a valid version number for macOS}}
+@available(iOS, deprecated: 20) // expected-warning {{'20' is not a valid version number for iOS}}
+@available(macCatalyst, deprecated: 20) // expected-warning {{'20' is not a valid version number for Mac Catalyst}}
+@available(watchOS, deprecated: 13) // expected-warning {{'13' is not a valid version number for watchOS}}
+@available(tvOS, deprecated: 20) // expected-warning {{'20' is not a valid version number for tvOS}}
+@available(visionOS, deprecated: 4) // expected-warning {{'4' is not a valid version number for visionOS}}
+func invalidDeprecated() { }
+
+@available(macOS, obsoleted: 17) // expected-warning {{'17' is not a valid version number for macOS}}
+@available(iOS, obsoleted: 20) // expected-warning {{'20' is not a valid version number for iOS}}
+@available(macCatalyst, obsoleted: 20) // expected-warning {{'20' is not a valid version number for Mac Catalyst}}
+@available(watchOS, obsoleted: 13) // expected-warning {{'13' is not a valid version number for watchOS}}
+@available(tvOS, obsoleted: 20) // expected-warning {{'20' is not a valid version number for tvOS}}
+@available(visionOS, obsoleted: 4) // expected-warning {{'4' is not a valid version number for visionOS}}
+func invalidObsoleted() { }
+
+@available(macOS 18, iOS 21, macCatalyst 22, watchOS 14, tvOS 23, visionOS 7, *)
+// expected-warning@-1 {{'18' is not a valid version number for macOS}}
+// expected-warning@-2 {{'21' is not a valid version number for iOS}}
+// expected-warning@-3 {{'22' is not a valid version number for Mac Catalyst}}
+// expected-warning@-4 {{'14' is not a valid version number for watchOS}}
+// expected-warning@-5 {{'23' is not a valid version number for tvOS}}
+// expected-warning@-6 {{'7' is not a valid version number for visionOS}}
+func invalidIntroducedShort() { }