[debugger] Ensure at least one breakable position per function.

src/interpreter/bytecode-generator.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/interpreter/bytecode-generator.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/interpreter/bytecode-register-allocator.h"
 #include "src/interpreter/control-flow-builders.h"
@@ skipping 602 matching lines @@
   // Build assignment to {new.target} variable if it is used.
   VisitNewTargetVariable(scope()->new_target_var());
 
   // TODO(rmcilroy): Emit tracing call if requested to do so.
   if (FLAG_trace) {
     UNIMPLEMENTED();
   }
 
   // Visit illegal re-declaration and bail out if it exists.
   if (scope()->HasIllegalRedeclaration()) {
-    VisitForEffect(scope()->GetIllegalRedeclaration());
+    Expression* illegal = scope()->GetIllegalRedeclaration();
+    builder()->SetExpressionAsStatementPosition(illegal);
+    VisitForEffect(illegal);
     return;
   }
 
   // Visit declarations within the function scope.
   VisitDeclarations(scope()->declarations());
 
   // Perform a stack-check before the body.
   builder()->StackCheck();
 
   // Visit statements in the function body.
@@ skipping 2506 matching lines @@
 }
 
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return info()->feedback_vector()->GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8