Backtick enum identifiers.

Refactored with this command

```
find . -type f -name "*.scala" -exec sed -i'' 's/\benum\b/`enum`/g' {} +
```

Author: olafurpg

compiler-plugin/src/main/scala/com/trueaccord/scalapb/compiler/DescriptorPimps.scala

@@ -372,10 +372,10 @@ trait DescriptorPimps {
     }
   }
 
-  implicit class EnumDescriptorPimp(val enum: EnumDescriptor) {
-    def parentMessage: Option[Descriptor] = Option(enum.getContainingType)
+  implicit class EnumDescriptorPimp(val `enum`: EnumDescriptor) {
+    def parentMessage: Option[Descriptor] = Option(`enum`.getContainingType)
 
-    def name: String = enum.getName match {
+    def name: String = `enum`.getName match {
       case "Option" => "OptionEnum"
       case n => n
     }
@@ -384,25 +384,25 @@ trait DescriptorPimps {
 
     lazy val scalaTypeName: String = parentMessage match {
       case Some(p) => p.scalaTypeName + "." + nameSymbol
-      case None => (enum.getFile.scalaPackagePartsAsSymbols :+ nameSymbol).mkString(".")
+      case None => (`enum`.getFile.scalaPackagePartsAsSymbols :+ nameSymbol).mkString(".")
     }
 
-    def isTopLevel = enum.getContainingType == null
+    def isTopLevel = `enum`.getContainingType == null
 
-    def javaTypeName = enum.getFile.fullJavaName(enum.getFullName)
+    def javaTypeName = `enum`.getFile.fullJavaName(`enum`.getFullName)
 
-    def javaConversions = enum.getFile.javaConversions
+    def javaConversions = `enum`.getFile.javaConversions
 
-    def valuesWithNoDuplicates = enum.getValues.asScala.groupBy(_.getNumber)
+    def valuesWithNoDuplicates = `enum`.getValues.asScala.groupBy(_.getNumber)
       .mapValues(_.head).values.toVector.sortBy(_.getNumber)
 
-    def javaDescriptorSource: String = if (enum.isTopLevel)
-      s"${enum.getFile.fileDescriptorObjectName}.javaDescriptor.getEnumTypes.get(${enum.getIndex})"
-      else s"${enum.getContainingType.scalaTypeName}.javaDescriptor.getEnumTypes.get(${enum.getIndex})"
+    def javaDescriptorSource: String = if (`enum`.isTopLevel)
+      s"${`enum`.getFile.fileDescriptorObjectName}.javaDescriptor.getEnumTypes.get(${`enum`.getIndex})"
+      else s"${`enum`.getContainingType.scalaTypeName}.javaDescriptor.getEnumTypes.get(${`enum`.getIndex})"
 
-    def scalaDescriptorSource: String = if (enum.isTopLevel)
-      s"${enum.getFile.fileDescriptorObjectName}.scalaDescriptor.enums(${enum.getIndex})"
-    else s"${enum.getContainingType.scalaTypeName}.scalaDescriptor.enums(${enum.getIndex})"
+    def scalaDescriptorSource: String = if (`enum`.isTopLevel)
+      s"${`enum`.getFile.fileDescriptorObjectName}.scalaDescriptor.enums(${`enum`.getIndex})"
+    else s"${`enum`.getContainingType.scalaTypeName}.scalaDescriptor.enums(${`enum`.getIndex})"
   }
 
   implicit class EnumValueDescriptorPimp(val enumValue: EnumValueDescriptor) {

compiler-plugin/src/main/scala/com/trueaccord/scalapb/compiler/ProtoValidation.scala

@@ -19,7 +19,7 @@ class ProtoValidation(val params: GeneratorParams) extends DescriptorPimps {
   def validateEnum(e: EnumDescriptor): Unit = {
     if (e.getValues.asScala.exists(_.getName.toUpperCase == "UNRECOGNIZED")) {
       throw new GeneratorException(
-        s"The enum value 'UNRECOGNIZED' in ${e.getName} is not allowed due to conflict with the catch-all " +
+        s"The `enum` value 'UNRECOGNIZED' in ${e.getName} is not allowed due to conflict with the catch-all " +
           "Unrecognized(v: Int) value.")
     }
   }

compiler-plugin/src/main/scala/com/trueaccord/scalapb/compiler/ProtobufGenerator.scala

@@ -1282,13 +1282,13 @@ class ProtobufGenerator(val params: GeneratorParams) extends DescriptorPimps {
     val serviceFiles = generateServiceFiles(file)
 
     val enumFiles = for {
-      enum <- file.getEnumTypes.asScala
+      `enum` <- file.getEnumTypes.asScala
     } yield {
       val b = CodeGeneratorResponse.File.newBuilder()
-      b.setName(file.scalaDirectory + "/" + enum.getName + ".scala")
+      b.setName(file.scalaDirectory + "/" + `enum`.getName + ".scala")
       b.setContent(
         scalaFileHeader(file)
-          .call(printEnum(_, enum)).result())
+          .call(printEnum(_, `enum`)).result())
       b.build
     }
 

e2e/src/test/scala/AnySpec.scala

@@ -2,8 +2,8 @@ import com.trueaccord.proto.any._
 import com.google.protobuf.any.Any
 import org.scalatest._
 import org.scalatest.prop._
-import com.trueaccord.proto.e2e.enum.EnumTest
-import com.trueaccord.proto.e2e.enum.Color
+import com.trueaccord.proto.e2e.`enum`.EnumTest
+import com.trueaccord.proto.e2e.`enum`.Color
 
 class AnySpec extends FlatSpec with MustMatchers {
   val green = EnumTest(color = Some(Color.GREEN))

e2e/src/test/scala/EnumSpec.scala

@@ -1,4 +1,4 @@
-import com.trueaccord.proto.e2e.enum._
+import com.trueaccord.proto.e2e.`enum`._
 import com.trueaccord.proto.e2e.enum3._
 import com.trueaccord.scalapb.GeneratedEnumCompanion
 import org.scalatest._
@@ -90,20 +90,20 @@ class EnumSpec extends FlatSpec with MustMatchers with OptionValues {
         innerEnum = Some(EnumTest.InnerEnum.OtherCase)))
   }
 
-  "missing enum values in proto3" should "be preserved in parsing" in {
+  "missing `enum` values in proto3" should "be preserved in parsing" in {
     val like = EnumTestLike(color = 18)  // same field number as `color` in EnumTest3.
     val e3 = EnumTest3.parseFrom(like.toByteArray)
     e3.color must be (Color3.Unrecognized(18))
     e3.color must not be (Color3.Unrecognized(19))
     e3.toByteArray must be (like.toByteArray)
   }
 
-  "missing enum values in proto3 seq" should "be preserved in parsing" in {
+  "missing `enum` values in proto3 seq" should "be preserved in parsing" in {
     val e3 = EnumTest3(colorVector = Seq(Color3.C3_RED, Color3.Unrecognized(15), Color3.C3_BLUE))
     EnumTest3.parseFrom(e3.toByteArray) must be (e3)
   }
 
-  "missing enum values in proto2" should "be preserved in parsing" in {
+  "missing `enum` values in proto2" should "be preserved in parsing" in {
     val like = EnumTestLike(color = 18)  // same field number as `color` in EnumTest3.
     val e3 = EnumTest.parseFrom(like.toByteArray)
     e3.getColor must be (Color.Unrecognized(18))

proptest/src/test/scala/GraphGen.scala

@@ -84,18 +84,18 @@ object GraphGen {
       .retryUntil {
         case (names, _) =>
           // In protoc there is a check that says:
-          //     When enum name is stripped and label is PascalCased (X), this value label conflicts
+          //     When `enum` name is stripped and label is PascalCased (X), this value label conflicts
           //     with abc_bar_x. This will make the proto fail to compile for some languages, such as C#.
           //
           // To eliminate any posssibility of triggering it, we don't allow labels (lower case, underscores removed)
-          // to start with the enum names (lower case, underscores removed)
+          // to start with the `enum` names (lower case, underscores removed)
           val enumNameCanon = enumName.toLowerCase.replaceAll("_", "")
           names.forall(n => !n.toLowerCase.replaceAll("_", "").startsWith(enumNameCanon)) &&
             namesAreUniqueAfterCamelCase(names)
         }
       values <- GenUtils.genListOfDistinctPositiveNumbers(names.size).map {
         v =>
-          // in proto3 the first enum value must be zero.
+          // in proto3 the first `enum` value must be zero.
           if (zeroDefined) v.updated(0, 0) else v
       }
     } yield (EnumNode(myId, enumName, names zip values,

proptest/src/test/scala/Nodes.scala

@@ -184,7 +184,7 @@ object Nodes {
         .add(fileReferences(rootNode).collect({
         case f if f != baseFileName => s"""import "${f}.proto";"""
       }).toSeq: _*)
-        .print(enums)((enum, p) => p.print(enum))
+        .print(enums)((`enum`, p) => p.print(`enum`))
         .print(messages)((message, p) => p.print(rootNode, this, message))
         .print(services)((service, p) => p.print(service))
 
@@ -253,7 +253,7 @@ object Nodes {
       printer
         .add(s"message $name {  // message $id")
         .indent
-        .print(enums)((enum, p) => p.print(enum))
+        .print(enums)((`enum`, p) => p.print(`enum`))
         .print(messages)((message, p) => p.print(rootNode, fileNode, message))
         .print(makeList(fields)) {
         case (printer, OneofOpener(name)) =>
@@ -296,7 +296,7 @@ object Nodes {
 
   case class EnumNode(id: Int, name: String, values: Seq[(String, Int)], parentMessageId: Option[Int], fileId: Int) {
     def print(printer: compiler.FunctionalPrinter): compiler.FunctionalPrinter = {
-      printer.add(s"enum $name {  // enum $id")
+      printer.add(s"`enum` $name {  // `enum` $id")
         .indent
         .add(values.map { case (s, v) => s"$s = $v;"}: _*)
         .outdent

proptest/src/test/scala/SchemaGenerators.scala

@@ -25,7 +25,7 @@ object SchemaGenerators {
     "boolean", "do", "if", "private", "this",
     "break", "double", "implements", "protected", "throw",
     "byte", "else", "import", "public", "throws",
-    "case", "enum", "instanceof", "return", "transient",
+    "case", "`enum`", "instanceof", "return", "transient",
     "catch", "extends", "int", "short", "try", "char", "final",
     "interface", "static", "void", "class", "finally",
     "long", "strictfp", "volatile", "const", "float",

scalapb-runtime/js/src/main/scala/com/google/protobuf/descriptor/EnumDescriptorProto.scala

@@ -7,7 +7,7 @@ package com.google.protobuf.descriptor
 
 
 
-/** Describes an enum type.
+/** Describes an `enum` type.
   */
 @SerialVersionUID(0L)
 final case class EnumDescriptorProto(

scalapb-runtime/js/src/main/scala/com/google/protobuf/descriptor/EnumOptions.scala

@@ -11,9 +11,9 @@ package com.google.protobuf.descriptor
   *   Set this option to true to allow mapping different tag names to the same
   *   value.
   * @param deprecated
-  *   Is this enum deprecated?
+  *   Is this `enum` deprecated?
   *   Depending on the target platform, this can emit Deprecated annotations
-  *   for the enum, or it will be completely ignored; in the very least, this
+  *   for the `enum`, or it will be completely ignored; in the very least, this
   *   is a formalization for deprecating enums.
   * @param uninterpretedOption
   *   The parser stores options it doesn't recognize here. See above.

scalapb-runtime/js/src/main/scala/com/google/protobuf/descriptor/EnumValueDescriptorProto.scala

@@ -7,7 +7,7 @@ package com.google.protobuf.descriptor
 
 
 
-/** Describes a value within an enum.
+/** Describes a value within an `enum`.
   */
 @SerialVersionUID(0L)
 final case class EnumValueDescriptorProto(

scalapb-runtime/js/src/main/scala/com/google/protobuf/descriptor/EnumValueOptions.scala

@@ -8,10 +8,10 @@ package com.google.protobuf.descriptor
 
 
 /** @param deprecated
-  *   Is this enum value deprecated?
+  *   Is this `enum` value deprecated?
   *   Depending on the target platform, this can emit Deprecated annotations
-  *   for the enum value, or it will be completely ignored; in the very least,
-  *   this is a formalization for deprecating enum values.
+  *   for the `enum` value, or it will be completely ignored; in the very least,
+  *   this is a formalization for deprecating `enum` values.
   * @param uninterpretedOption
   *   The parser stores options it doesn't recognize here. See above.
   */

scalapb-runtime/js/src/main/scala/com/google/protobuf/descriptor/FieldDescriptorProto.scala

@@ -13,7 +13,7 @@ package com.google.protobuf.descriptor
   *   If type_name is set, this need not be set.  If both this and type_name
   *   are set, this must be one of TYPE_ENUM, TYPE_MESSAGE or TYPE_GROUP.
   * @param typeName
-  *   For message and enum types, this is the name of the type.  If the name
+  *   For message and `enum` types, this is the name of the type.  If the name
   *   starts with a '.', it is fully-qualified.  Otherwise, C++-like scoping
   *   rules are used to find the type (i.e. first the nested types within this
   *   message are searched, then within the parent, on up to the root

scalapb-runtime/js/src/main/scala/com/google/protobuf/descriptor/FieldOptions.scala

@@ -26,7 +26,7 @@ package com.google.protobuf.descriptor
   *   happen when a large value is converted to a floating point JavaScript
   *   numbers.  Specifying JS_NUMBER for the jstype causes the generated
   *   JavaScript code to use the JavaScript "number" type instead of strings.
-  *   This option is an enum to permit additional types to be added,
+  *   This option is an `enum` to permit additional types to be added,
   *   e.g. goog.math.Integer.
   * @param lazy
   *   Should this field be parsed lazily?  Lazy applies only to message-type

scalapb-runtime/js/src/main/scala/com/google/protobuf/descriptor/FileOptions.scala

@@ -20,7 +20,7 @@ package com.google.protobuf.descriptor
   *   explicitly choose the class name).
   * @param javaMultipleFiles
   *   If set true, then the Java code generator will generate a separate .java
-  *   file for each top-level message, enum, and service defined in the .proto
+  *   file for each top-level message, `enum`, and service defined in the .proto
   *   file.  Thus, these types will *not* be nested inside the outer class
   *   named by java_outer_classname.  However, the outer class will still be
   *   generated to contain the file's getDescriptor() method as well as any

scalapb-runtime/jvm/src/main/scala/com/google/protobuf/descriptor/EnumDescriptorProto.scala

@@ -7,7 +7,7 @@ package com.google.protobuf.descriptor
 
 import scala.collection.JavaConverters._
 
-/** Describes an enum type.
+/** Describes an `enum` type.
   */
 @SerialVersionUID(0L)
 final case class EnumDescriptorProto(

scalapb-runtime/jvm/src/main/scala/com/google/protobuf/descriptor/EnumOptions.scala

@@ -11,9 +11,9 @@ import scala.collection.JavaConverters._
   *   Set this option to true to allow mapping different tag names to the same
   *   value.
   * @param deprecated
-  *   Is this enum deprecated?
+  *   Is this `enum` deprecated?
   *   Depending on the target platform, this can emit Deprecated annotations
-  *   for the enum, or it will be completely ignored; in the very least, this
+  *   for the `enum`, or it will be completely ignored; in the very least, this
   *   is a formalization for deprecating enums.
   * @param uninterpretedOption
   *   The parser stores options it doesn't recognize here. See above.

scalapb-runtime/jvm/src/main/scala/com/google/protobuf/descriptor/EnumValueDescriptorProto.scala

@@ -7,7 +7,7 @@ package com.google.protobuf.descriptor
 
 import scala.collection.JavaConverters._
 
-/** Describes a value within an enum.
+/** Describes a value within an `enum`.
   */
 @SerialVersionUID(0L)
 final case class EnumValueDescriptorProto(

scalapb-runtime/jvm/src/main/scala/com/google/protobuf/descriptor/EnumValueOptions.scala

@@ -8,10 +8,10 @@ package com.google.protobuf.descriptor
 import scala.collection.JavaConverters._
 
 /** @param deprecated
-  *   Is this enum value deprecated?
+  *   Is this `enum` value deprecated?
   *   Depending on the target platform, this can emit Deprecated annotations
-  *   for the enum value, or it will be completely ignored; in the very least,
-  *   this is a formalization for deprecating enum values.
+  *   for the `enum` value, or it will be completely ignored; in the very least,
+  *   this is a formalization for deprecating `enum` values.
   * @param uninterpretedOption
   *   The parser stores options it doesn't recognize here. See above.
   */

scalapb-runtime/jvm/src/main/scala/com/google/protobuf/descriptor/FieldDescriptorProto.scala

@@ -13,7 +13,7 @@ import scala.collection.JavaConverters._
   *   If type_name is set, this need not be set.  If both this and type_name
   *   are set, this must be one of TYPE_ENUM, TYPE_MESSAGE or TYPE_GROUP.
   * @param typeName
-  *   For message and enum types, this is the name of the type.  If the name
+  *   For message and `enum` types, this is the name of the type.  If the name
   *   starts with a '.', it is fully-qualified.  Otherwise, C++-like scoping
   *   rules are used to find the type (i.e. first the nested types within this
   *   message are searched, then within the parent, on up to the root

scalapb-runtime/jvm/src/main/scala/com/google/protobuf/descriptor/FieldOptions.scala

@@ -26,7 +26,7 @@ import scala.collection.JavaConverters._
   *   happen when a large value is converted to a floating point JavaScript
   *   numbers.  Specifying JS_NUMBER for the jstype causes the generated
   *   JavaScript code to use the JavaScript "number" type instead of strings.
-  *   This option is an enum to permit additional types to be added,
+  *   This option is an `enum` to permit additional types to be added,
   *   e.g. goog.math.Integer.
   * @param lazy
   *   Should this field be parsed lazily?  Lazy applies only to message-type

scalapb-runtime/jvm/src/main/scala/com/google/protobuf/descriptor/FileOptions.scala

@@ -20,7 +20,7 @@ import scala.collection.JavaConverters._
   *   explicitly choose the class name).
   * @param javaMultipleFiles
   *   If set true, then the Java code generator will generate a separate .java
-  *   file for each top-level message, enum, and service defined in the .proto
+  *   file for each top-level message, `enum`, and service defined in the .proto
   *   file.  Thus, these types will *not* be nested inside the outer class
   *   named by java_outer_classname.  However, the outer class will still be
   *   generated to contain the file's getDescriptor() method as well as any

scalapb-runtime/shared/src/main/scala/scalapb/descriptors/Descriptor.scala

@@ -189,7 +189,7 @@ object FieldDescriptor {
           case Some(e: EnumDescriptor) =>
             ScalaType.Enum(e)
           case None =>
-            throw new DescriptorValidationException(m, s"Could not find enum ${field.getTypeName} for field ${field.getName}")
+            throw new DescriptorValidationException(m, s"Could not find `enum` ${field.getTypeName} for field ${field.getName}")
           case Some(_) =>
             throw new DescriptorValidationException(m, s"Invalid type ${field.getTypeName} for field ${field.getName}")
         }

scalapb-runtime/shared/src/test/scala/scalapb/descriptors/FileDescriptorSpec.scala

@@ -188,7 +188,7 @@ class FileDescriptorSpec extends FlatSpec with MustMatchers with OptionValues {
     }.getMessage must be ("mypkg.Msg1: Invalid type TheEnum for field ff")
   }
 
-  "buildFrom" should "fail when enum ref type is not an enum" in {
+  "buildFrom" should "fail when `enum` ref type is not an `enum`" in {
     val fdp = FileDescriptorProto.fromAscii(
       """package: "mypkg"
         |message_type {