Sema: Fix crash on Linux if ObjCBool type is not present

Author: slavapestov

include/swift/AST/DiagnosticsSema.def

@@ -2166,9 +2166,6 @@ ERROR(builtin_string_literal_broken_proto,none,
 ERROR(string_literal_broken_proto,none,
       "protocol 'ExpressibleByStringLiteral' is broken", ())
 
-ERROR(bool_type_broken,none,
-      "could not find a Bool type defined for 'is'", ())
-
 // Array literals
 ERROR(array_protocol_broken,none,
       "ExpressibleByArrayLiteral protocol definition is broken", ())

lib/Sema/TypeCheckType.cpp

@@ -3025,8 +3025,19 @@ bool TypeChecker::isRepresentableInObjC(
       // Functions that return nothing (void) can be throwing; they indicate
       // failure with a 'false' result.
       kind = ForeignErrorConvention::ZeroResult;
-      errorResultType = Context.getObjCBoolDecl()
-                          ->getDeclaredInterfaceType()->getCanonicalType();
+      NominalTypeDecl *boolDecl = Context.getObjCBoolDecl();
+      // On Linux, we might still run @objc tests even though there's
+      // no ObjectiveC Foundation, so use Swift.Bool instead of crapping
+      // out.
+      if (boolDecl == nullptr)
+        boolDecl = Context.getBoolDecl();
+
+      if (boolDecl == nullptr) {
+        diagnose(AFD->getLoc(), diag::broken_bool);
+        return false;
+      }
+
+      errorResultType = boolDecl->getDeclaredType()->getCanonicalType();
     } else if (!resultType->getAnyOptionalObjectType() &&
                isBridgedToObjectiveCClass(dc, resultType)) {
       // Functions that return a (non-optional) type bridged to Objective-C

lib/Sema/TypeChecker.cpp

@@ -243,13 +243,13 @@ Type TypeChecker::lookupBoolType(const DeclContext *dc) {
       getStdlibModule(dc)->lookupValue({}, Context.getIdentifier("Bool"),
                                        NLKind::QualifiedLookup, results);
       if (results.size() != 1) {
-        diagnose(SourceLoc(), diag::bool_type_broken);
+        diagnose(SourceLoc(), diag::broken_bool);
         return Type();
       }
 
       auto tyDecl = dyn_cast<TypeDecl>(results.front());
       if (!tyDecl) {
-        diagnose(SourceLoc(), diag::bool_type_broken);
+        diagnose(SourceLoc(), diag::broken_bool);
         return Type();
       }