diff --git a/protobuf/benchmarks/common.dart b/protobuf/benchmarks/common.dart
index 9259375..05e6918 100644
--- a/protobuf/benchmarks/common.dart
+++ b/protobuf/benchmarks/common.dart
@@ -71,7 +71,7 @@
   final FromJsonFactory fromJson;
 
   static Factories forMessage(String name) =>
-      _factories[name] ?? (throw 'Unsupported message: ${name}');
+      _factories[name] ?? (throw 'Unsupported message: $name');
 
   /// Mapping between [BenchmarkProto.messageName] and corresponding
   /// deserialization factories.
diff --git a/protobuf/lib/src/protobuf/extension_field_set.dart b/protobuf/lib/src/protobuf/extension_field_set.dart
index 8819750..8998042 100644
--- a/protobuf/lib/src/protobuf/extension_field_set.dart
+++ b/protobuf/lib/src/protobuf/extension_field_set.dart
@@ -160,7 +160,7 @@
       if (value == null) continue;
       if (extension.isRepeated) {
         assert(value is PbListBase);
-        _ensureRepeatedField(extension)..addAll(value);
+        _ensureRepeatedField(extension).addAll(value);
       } else {
         _setFieldUnchecked(extension, value);
       }
diff --git a/protobuf/lib/src/protobuf/field_error.dart b/protobuf/lib/src/protobuf/field_error.dart
index fdbedb6..54e04be 100644
--- a/protobuf/lib/src/protobuf/field_error.dart
+++ b/protobuf/lib/src/protobuf/field_error.dart
@@ -68,7 +68,7 @@
 
 // generated checkItem for message, group, enum calls this
 void checkItemFailed(val, String className) {
-  throw ArgumentError('Value ($val) is not an instance of ${className}');
+  throw ArgumentError('Value ($val) is not an instance of $className');
 }
 
 /// Returns a function for validating items in a repeated field.
@@ -107,7 +107,7 @@
     case PbFieldType._FIXED32_BIT:
       return _checkUnsigned32;
   }
-  throw ArgumentError('check function not implemented: ${fieldType}');
+  throw ArgumentError('check function not implemented: $fieldType');
 }
 
 // check functions for repeated fields
@@ -133,7 +133,7 @@
 }
 
 RangeError _createFieldRangeError(val, String wantedType) =>
-    RangeError('Value ($val) is not ${wantedType}');
+    RangeError('Value ($val) is not $wantedType');
 
 bool _isSigned32(int value) => (-2147483648 <= value) && (value <= 2147483647);
 
diff --git a/protobuf/lib/src/protobuf/generated_message.dart b/protobuf/lib/src/protobuf/generated_message.dart
index 8bbbf5a..0f1446a 100644
--- a/protobuf/lib/src/protobuf/generated_message.dart
+++ b/protobuf/lib/src/protobuf/generated_message.dart
@@ -296,7 +296,7 @@
       throw ArgumentError(
           'Cannot add to a non-repeated field (use setExtension())');
     }
-    _fieldSet._ensureExtensions().._ensureRepeatedField(extension).add(value);
+    _fieldSet._ensureExtensions()._ensureRepeatedField(extension).add(value);
   }
 
   /// Clears an extension field and also removes the extension.
diff --git a/protobuf/lib/src/protobuf/mixins/map_mixin.dart b/protobuf/lib/src/protobuf/mixins/map_mixin.dart
index 2608fb0..2c32c71 100644
--- a/protobuf/lib/src/protobuf/mixins/map_mixin.dart
+++ b/protobuf/lib/src/protobuf/mixins/map_mixin.dart
@@ -32,7 +32,7 @@
     var tag = getTagNumber(key as String);
     if (tag == null) {
       throw ArgumentError(
-          "field '${key}' not found in ${info_.qualifiedMessageName}");
+          "field '$key' not found in ${info_.qualifiedMessageName}");
     }
     setField(tag, val);
   }
diff --git a/protobuf/lib/src/protobuf/mixins/well_known.dart b/protobuf/lib/src/protobuf/mixins/well_known.dart
index 73b4980..496823f 100644
--- a/protobuf/lib/src/protobuf/mixins/well_known.dart
+++ b/protobuf/lib/src/protobuf/mixins/well_known.dart
@@ -46,7 +46,7 @@
   static void packIntoAny(AnyMixin target, GeneratedMessage message,
       {String typeUrlPrefix = 'type.googleapis.com'}) {
     target.value = message.writeToBuffer();
-    target.typeUrl = '${typeUrlPrefix}/${message.info_.qualifiedMessageName}';
+    target.typeUrl = '$typeUrlPrefix/${message.info_.qualifiedMessageName}';
   }
 
   // From google/protobuf/any.proto:
@@ -110,7 +110,7 @@
       var info = typeRegistry.lookup(_typeNameFromUrl(typeUrl));
       if (info == null) {
         throw context.parseException(
-            'Decoding Any of type ${typeUrl} not in TypeRegistry $typeRegistry',
+            'Decoding Any of type $typeUrl not in TypeRegistry $typeRegistry',
             json);
       }
 
@@ -166,8 +166,8 @@
   }
 
   static String _twoDigits(int n) {
-    if (n >= 10) return '${n}';
-    return '0${n}';
+    if (n >= 10) return '$n';
+    return '0$n';
   }
 
   static final DateTime _minTimestamp = DateTime.utc(1);
@@ -488,8 +488,9 @@
         // The empty string splits to a single value. So this is a special case.
         return;
       }
-      (message as FieldMaskMixin).paths
-        ..addAll(json.split(',').map(_fromCamelCase));
+      (message as FieldMaskMixin)
+          .paths
+          .addAll(json.split(',').map(_fromCamelCase));
     } else {
       throw context.parseException(
           'Expected String formatted as FieldMask', json);
diff --git a/protobuf/lib/src/protobuf/unknown_field_set.dart b/protobuf/lib/src/protobuf/unknown_field_set.dart
index 92ffdf4..3ec54cb 100644
--- a/protobuf/lib/src/protobuf/unknown_field_set.dart
+++ b/protobuf/lib/src/protobuf/unknown_field_set.dart
@@ -158,15 +158,15 @@
       for (var value in field.values) {
         if (value is UnknownFieldSet) {
           stringBuffer
-            ..write('${indent}${tag}: {\n')
+            ..write('$indent$tag: {\n')
             ..write(value._toString('$indent  '))
-            ..write('${indent}}\n');
+            ..write('$indent}\n');
         } else {
           if (value is ByteData) {
             // TODO(antonm): fix for longs.
             value = value.getUint64(0, Endian.little);
           }
-          stringBuffer.write('${indent}${tag}: ${value}\n');
+          stringBuffer.write('$indent$tag: $value\n');
         }
       }
     }
diff --git a/protobuf/test/map_mixin_test.dart b/protobuf/test/map_mixin_test.dart
index e37529d..2e40c5b 100644
--- a/protobuf/test/map_mixin_test.dart
+++ b/protobuf/test/map_mixin_test.dart
@@ -24,7 +24,7 @@
   Rec createEmptyInstance() => Rec();
 
   @override
-  String toString() => 'Rec(${val}, "${str}")';
+  String toString() => 'Rec($val, "$str")';
 }
 
 void main() {