Check Swift reserved names when generating function names

Sources/protoc-gen-grpc-swift/Generator-Names.swift

@@ -69,13 +69,58 @@ extension Generator {
     return nameForPackageServiceMethod(file, service, method) + "Call"
   }
 
+  internal let quotableFieldNames: Set<String> = {
+    () -> Set<String> in
+    var names: Set<String> = []
+
+    names = names.union(swiftKeywordsUsedInDeclarations)
+    names = names.union(swiftKeywordsUsedInStatements)
+    names = names.union(swiftKeywordsUsedInExpressionsAndTypes)
+    return names
+  }()
+
+  internal let swiftKeywordsUsedInDeclarations: Set<String> = [
+    "associatedtype", "class", "deinit", "enum", "extension",
+    "fileprivate", "func", "import", "init", "inout", "internal",
+    "let", "open", "operator", "private", "protocol", "public",
+    "static", "struct", "subscript", "typealias", "var"
+  ]
+
+  internal let swiftKeywordsUsedInStatements: Set<String> = [ "break", "case",
+    "continue", "default", "defer", "do", "else", "fallthrough",
+    "for", "guard", "if", "in", "repeat", "return", "switch", "where",
+    "while"
+  ]
+
+  internal let swiftKeywordsUsedInExpressionsAndTypes: Set<String> = [ "as",
+    "Any", "catch", "false", "is", "nil", "rethrows", "super", "self",
+    "Self", "throw", "throws", "true", "try"
+  ]
+
+  internal let quotableFieldNames: Set<String> = {
+    () -> Set<String> in
+    var names: Set<String> = []
+
+    names = names.union(swiftKeywordsUsedInDeclarations)
+    names = names.union(swiftKeywordsUsedInStatements)
+    names = names.union(swiftKeywordsUsedInExpressionsAndTypes)
+      return names
+  }()
+
   internal var methodFunctionName: String {
-    let name = method.name
-    if self.options.keepMethodCasing {
-      return name
-    } else {
-      return name.prefix(1).lowercased() + name.dropFirst()
+    var name = method.name
+    if !self.options.keepMethodCasing {
+      name = name.prefix(1).lowercased() + name.dropFirst()
+    }
+
+    return sanitize(fieldName: name)
+  }
+
+  internal func sanitize(fieldName string: String) -> String {
+    if quotableFieldNames.contains(string) {
+      return "`\(string)`"
     }
+    return string
   }
 
   internal var methodInputName: String {