Implement correct semantics of Boolean Conversion

runtime/vm/code_generator.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/code_generator.h"
 
 #include "vm/assembler.h"
 #include "vm/ast.h"
 #include "vm/code_patcher.h"
 #include "vm/compiler.h"
@@ skipping 36 matching lines @@
 DEFINE_FLAG(bool, trace_ic, false, "Trace IC handling");
 DEFINE_FLAG(bool, trace_ic_miss_in_optimized, false,
     "Trace IC miss in optimized code");
 DEFINE_FLAG(bool, trace_optimized_ic_calls, false,
     "Trace IC calls in optimized code.");
 DEFINE_FLAG(bool, trace_patching, false, "Trace patching of code.");
 DEFINE_FLAG(bool, trace_runtime_calls, false, "Trace runtime calls");
 DEFINE_FLAG(bool, trace_type_checks, false, "Trace runtime type checks.");
 
 DECLARE_FLAG(int, deoptimization_counter_threshold);
+DECLARE_FLAG(bool, enable_asserts);
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, warn_on_javascript_compatibility);
 
 DEFINE_FLAG(bool, use_osr, true, "Use on-stack replacement.");
 DEFINE_FLAG(bool, trace_osr, false, "Trace attempts at on-stack replacement.");
 
 DEFINE_FLAG(int, stacktrace_every, 0,
             "Compute debugger stacktrace on every N stack overflow checks");
 DEFINE_FLAG(charp, stacktrace_filter, NULL,
             "Compute stacktrace in named function on stack overflow checks");
@@ skipping 485 matching lines @@
     UNREACHABLE();
   }
   UpdateTypeTestCache(src_instance, dst_type,
                       dst_instantiator, instantiator_type_arguments,
                       Bool::True(), cache);
   arguments.SetReturn(src_instance);
 }
 
 
 // Report that the type of the given object is not bool in conditional context.
+// Throw assertion error if the object is null. (cf. Boolean Conversion
+// in language Spec.)
 // Arg0: bad object.
-// Return value: none, throws a TypeError.
+// Return value: none, throws TypeError or AssertionError.
 DEFINE_RUNTIME_ENTRY(NonBoolTypeError, 1) {
   const intptr_t location = GetCallerLocation();
   const Instance& src_instance = Instance::CheckedHandle(arguments.ArgAt(0));
-  ASSERT(src_instance.IsNull() || !src_instance.IsBool());
+
+  if (src_instance.IsNull()) {
+    const Array& args = Array::Handle(Array::New(4));
+    args.SetAt(0, String::Handle(
+        String::New("Failed assertion: boolean expression must not be null")));
+
+    // No source code for this assertion, set url to null.
+    args.SetAt(1, String::Handle(String::null()));
+    args.SetAt(2, Smi::Handle(Smi::New(0)));
+    args.SetAt(3, Smi::Handle(Smi::New(0)));
+
+    Exceptions::ThrowByType(Exceptions::kAssertion, args);
+    UNREACHABLE();
+  }
+
+  ASSERT(!src_instance.IsBool());
   const Type& bool_interface = Type::Handle(Type::BoolType());
   const AbstractType& src_type = AbstractType::Handle(src_instance.GetType());
   const String& src_type_name = String::Handle(src_type.UserVisibleName());
   const String& bool_type_name =
       String::Handle(bool_interface.UserVisibleName());
   const String& no_bound_error = String::Handle();
   Exceptions::CreateAndThrowTypeError(location, src_type_name, bool_type_name,
                                       Symbols::BooleanExpression(),
                                       no_bound_error);
   UNREACHABLE();
@@ skipping 1049 matching lines @@
   field.RecordStore(value);
 }
 
 
 DEFINE_RUNTIME_ENTRY(InitStaticField, 1) {
   const Field& field = Field::CheckedHandle(arguments.ArgAt(0));
   field.EvaluateInitializer();
 }
 
 }  // namespace dart