update to kotlin 1.2.50
diff --git a/kotlin/builder/src/io/bazel/kotlin/builder/KotlinToolchain.kt b/kotlin/builder/src/io/bazel/kotlin/builder/KotlinToolchain.kt
index 7219f43..36be75f 100644
--- a/kotlin/builder/src/io/bazel/kotlin/builder/KotlinToolchain.kt
+++ b/kotlin/builder/src/io/bazel/kotlin/builder/KotlinToolchain.kt
@@ -137,7 +137,7 @@
             val compilerClass = classloader.loadClass("io.bazel.kotlin.compiler.BazelK2JVMCompiler")
             val exitCodeClass = classloader.loadClass("org.jetbrains.kotlin.cli.common.ExitCode")
 
-            val compiler = compilerClass.newInstance()
+            val compiler = compilerClass.getConstructor().newInstance()
             val execMethod = compilerClass.getMethod("exec", PrintStream::class.java, Array<String>::class.java)
             val getCodeMethod = exitCodeClass.getMethod("getCode")
 
diff --git a/kotlin/kotlin_compiler_repositories.bzl b/kotlin/kotlin_compiler_repositories.bzl
index a886ceb..5f56c85 100644
--- a/kotlin/kotlin_compiler_repositories.bzl
+++ b/kotlin/kotlin_compiler_repositories.bzl
@@ -24,6 +24,11 @@
 )
 
 KOTLIN_RELEASES = {
+    "1.2.50": {
+      "version": "1.2.50",
+      "url": "https://github.com/JetBrains/kotlin/releases/download/v1.2.50/kotlin-compiler-1.2.50.zip",
+      "sha256": "bc062c303b376711097a27bda4c28047eda0744e9acc64b9db640c19c7d171a9"
+    },
     "1.2.41": {
       "version": "1.2.41",
       "url": "https://github.com/JetBrains/kotlin/releases/download/v1.2.41/kotlin-compiler-1.2.41.zip",
@@ -167,7 +172,7 @@
 exports_files(["src"])
 """
 
-KOTLIN_CURRENT_RELEASE = "1.2.41"
+KOTLIN_CURRENT_RELEASE = "1.2.50"
 
 _BAZEL_JAVA_LAUNCHER_VERSION = "0.8.1"