Merge pull request #33932 from rockbruno/negative-aval

[SE-0290] Add #unavailable (Negative platform checks)

Author: varungandhi-apple

include/swift/AST/DiagnosticsParse.def

@@ -931,6 +931,12 @@ WARNING(parameter_unnamed_warn,none,
 ERROR(parameter_curry_syntax_removed,none,
       "cannot have more than one parameter list", ())
 
+ERROR(availability_cannot_be_mixed,none,
+      "#available and #unavailable cannot be in the same statement", ())
+
+ERROR(false_available_is_called_unavailable,none,
+      "#available cannot be used as an expression, did you mean to use '#unavailable'?", ())
+
 ERROR(initializer_as_typed_pattern,none,
       "unexpected initializer in pattern; did you mean to use '='?", ())
 
@@ -1223,8 +1229,8 @@ ERROR(invalid_float_literal_missing_leading_zero,none,
       "'.%0' is not a valid floating point literal; it must be written '0.%0'",
       (StringRef))
 ERROR(availability_query_outside_if_stmt_guard, none,
-      "#available may only be used as condition of an 'if', 'guard'"
-      " or 'while' statement", ())
+      "%0 may only be used as condition of an 'if', 'guard'"
+      " or 'while' statement", (StringRef))
 
 ERROR(empty_arg_label_underscore, none,
       "an empty argument label is spelled with '_'", ())
@@ -1812,14 +1818,17 @@ ERROR(avail_query_version_comparison_not_needed,
 ERROR(availability_query_wildcard_required, none,
       "must handle potential future platforms with '*'", ())
 
+ERROR(unavailability_query_wildcard_not_required, none,
+      "platform wildcard '*' is always implicit in #unavailable", ())
+
 ERROR(availability_must_occur_alone, none,
       "'%0' version-availability must be specified alone", (StringRef))
 
 ERROR(pound_available_swift_not_allowed, none,
-      "Swift language version checks not allowed in #available(...)", ())
+      "Swift language version checks not allowed in %0(...)", (StringRef))
 
 ERROR(pound_available_package_description_not_allowed, none,
-      "PackageDescription version checks not allowed in #available(...)", ())
+      "PackageDescription version checks not allowed in %0(...)", (StringRef))
 
 ERROR(availability_query_repeated_platform, none,
       "version for '%0' already specified", (StringRef))

include/swift/AST/Stmt.h

@@ -341,11 +341,17 @@ class alignas(8) PoundAvailableInfo final :
   /// This is filled in by Sema.
   VersionRange VariantAvailableRange;
 
+  /// Indicates that the expression is checking if a version range 
+  /// is **not** available.
+  bool _isUnavailability;
+
   PoundAvailableInfo(SourceLoc PoundLoc, SourceLoc LParenLoc,
-                     ArrayRef<AvailabilitySpec *> queries, SourceLoc RParenLoc)
+                     ArrayRef<AvailabilitySpec *> queries, SourceLoc RParenLoc,
+                     bool isUnavailability)
    : PoundLoc(PoundLoc), LParenLoc(LParenLoc), RParenLoc(RParenLoc),
      NumQueries(queries.size()), AvailableRange(VersionRange::empty()),
-     VariantAvailableRange(VersionRange::empty()) {
+     VariantAvailableRange(VersionRange::empty()), 
+     _isUnavailability(isUnavailability) {
     std::uninitialized_copy(queries.begin(), queries.end(),
                             getTrailingObjects<AvailabilitySpec *>());
   }
@@ -354,7 +360,8 @@ class alignas(8) PoundAvailableInfo final :
   static PoundAvailableInfo *create(ASTContext &ctx, SourceLoc PoundLoc,
                                     SourceLoc LParenLoc,
                                     ArrayRef<AvailabilitySpec *> queries,
-                                    SourceLoc RParenLoc);
+                                    SourceLoc RParenLoc,
+                                    bool isUnavailability);
 
   ArrayRef<AvailabilitySpec *> getQueries() const {
     return llvm::makeArrayRef(getTrailingObjects<AvailabilitySpec *>(),
@@ -379,6 +386,8 @@ class alignas(8) PoundAvailableInfo final :
   void setVariantAvailableRange(const VersionRange &Range) {
     VariantAvailableRange = Range;
   }
+
+  bool isUnavailability() const { return _isUnavailability; }
 };
 
 

include/swift/Parse/Parser.h

@@ -1769,11 +1769,21 @@ class Parser {
   //===--------------------------------------------------------------------===//
   // Availability Specification Parsing
 
+  /// The source of an availability spec list.
+  enum class AvailabilitySpecSource: uint8_t {
+    /// A spec from '@available(<spec>, ...)' or '#available(<spec>, ...)'.
+    Available,
+    /// A spec from '#unavailable(<spec>, ...)'.
+    Unavailable,
+    /// A spec from a '-define-availability "Name:<spec>, ..."' frontend arg.
+    Macro,
+  };
+
   /// Parse a comma-separated list of availability specifications. Try to
-  /// expand availability macros when /p ParsingMacroDefinition is false.
+  /// expand availability macros when /p Source is not a command line macro.
   ParserStatus
   parseAvailabilitySpecList(SmallVectorImpl<AvailabilitySpec *> &Specs,
-                            bool ParsingMacroDefinition = false);
+                            AvailabilitySpecSource Source);
 
   /// Does the current matches an argument macro name? Parsing compiler
   /// arguments as required without consuming tokens from the source file

lib/AST/Stmt.cpp

@@ -281,15 +281,15 @@ void LabeledConditionalStmt::setCond(StmtCondition e) {
   Cond = e;
 }
 
-PoundAvailableInfo *PoundAvailableInfo::create(ASTContext &ctx,
-                                               SourceLoc PoundLoc,
-                                               SourceLoc LParenLoc,
-                                       ArrayRef<AvailabilitySpec *> queries,
-                                                     SourceLoc RParenLoc) {
+PoundAvailableInfo *
+PoundAvailableInfo::create(ASTContext &ctx, SourceLoc PoundLoc,
+                           SourceLoc LParenLoc,
+                           ArrayRef<AvailabilitySpec *> queries,
+                           SourceLoc RParenLoc, bool isUnavailability) {
   unsigned size = totalSizeToAlloc<AvailabilitySpec *>(queries.size());
   void *Buffer = ctx.Allocate(size, alignof(PoundAvailableInfo));
   return ::new (Buffer) PoundAvailableInfo(PoundLoc, LParenLoc, queries,
-                                           RParenLoc);
+                                           RParenLoc, isUnavailability);
 }
 
 SourceLoc PoundAvailableInfo::getEndLoc() const {

lib/Parse/ParseDecl.cpp

@@ -2294,7 +2294,8 @@ bool Parser::parseNewDeclAttribute(DeclAttributes &Attributes, SourceLoc AtLoc,
          peekAvailabilityMacroName())) {
       // We have the short form of available: @available(iOS 8.0.1, *)
       SmallVector<AvailabilitySpec *, 5> Specs;
-      ParserStatus Status = parseAvailabilitySpecList(Specs);
+      ParserStatus Status = parseAvailabilitySpecList(Specs, 
+                                    AvailabilitySpecSource::Available);
 
       if (Status.isErrorOrHasCompletion())
         return false;

lib/Parse/ParseExpr.cpp

@@ -229,7 +229,7 @@ ParserResult<Expr> Parser::parseExprSequence(Diag<> Message,
       // this, because then we can produce a fixit to rewrite the && into a ,
       // if we're in a stmt-condition.
       if (Tok.getText() == "&&" &&
-          peekToken().isAny(tok::pound_available,
+          peekToken().isAny(tok::pound_available, tok::pound_unavailable,
                             tok::kw_let, tok::kw_var, tok::kw_case))
         goto done;
 
@@ -1745,10 +1745,12 @@ ParserResult<Expr> Parser::parseExprPrimary(Diag<> ID, bool isExprBasic) {
   case tok::l_square:
     return parseExprCollection();
 
-  case tok::pound_available: {
-    // For better error recovery, parse but reject #available in an expr
+  case tok::pound_available:
+  case tok::pound_unavailable: {
+    // For better error recovery, parse but reject availability in an expr
     // context.
-    diagnose(Tok.getLoc(), diag::availability_query_outside_if_stmt_guard);
+    diagnose(Tok.getLoc(), diag::availability_query_outside_if_stmt_guard, 
+             Tok.getText());
     auto res = parseStmtConditionPoundAvailable();
     if (res.hasCodeCompletion())
       return makeParserCodeCompletionStatus();