Validate that int values that we write to summaries are >= 0.

pkg/analyzer/tool/summary/generate.dart

 // Copyright (c) 2015, 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.
 
 /**
  * This file contains code to generate serialization/deserialization logic for
  * summaries based on an "IDL" description of the summary format (written in
  * stylized Dart).
  *
  * For each class in the "IDL" input, two corresponding classes are generated:
@@ skipping 294 matching lines @@
       out();
       for (idlModel.FieldDeclaration field in cls.fields) {
         String fieldName = field.name;
         idlModel.FieldType type = field.type;
         String typeStr = encodedType(type);
         out('$typeStr _$fieldName;');
       }
       // Generate getters and setters.
       for (idlModel.FieldDeclaration field in cls.fields) {
         String fieldName = field.name;
-        String typeStr = encodedType(field.type);
-        String def = defaultValue(field.type);
+        idlModel.FieldType fieldType = field.type;
+        String typeStr = encodedType(fieldType);
+        String def = defaultValue(fieldType);
         String defSuffix = def == null ? '' : ' ?? $def';
         out();
         out('@override');
-        out('${dartType(field.type)} get $fieldName => _$fieldName$defSuffix;');
+        out('${dartType(fieldType)} get $fieldName => _$fieldName$defSuffix;');
         out();
         outDoc(field.documentation);
         constructorParams.add('$typeStr $fieldName');
         out('void set $fieldName($typeStr _value) {');
         indent(() {
           String stateFieldName = '_' + fieldName;
           out('assert(!_finished);');
+          // Validate that int(s) are non-negative.
+          if (fieldType.typeName == 'int') {
+            if (!fieldType.isList) {
+              out('assert(_value == null || _value >= 0);');
+            } else {
+              out('assert(_value == null || _value.every((e) => e >= 0));');
+            }
+          }
+          // Set the value.
           out('$stateFieldName = _value;');
         });
         out('}');
       }
       // Generate constructor.
       out();
       out('$builderName({${constructorParams.join(', ')}})');
       for (int i = 0; i < cls.fields.length; i++) {
         idlModel.FieldDeclaration field = cls.fields[i];
         String prefix = i == 0 ? '  : ' : '    ';
@@ skipping 282 matching lines @@
       return token.lexeme.split('\n').map((String line) {
         if (line.startsWith(indent)) {
           line = line.substring(indent.length);
         }
         return line;
       }).join('\n');
     }
     return null;
   }
 }