diff --git a/arrow-annotations/build.gradle b/arrow-annotations/build.gradle
index 2a13bcb43..5923ee60d 100644
--- a/arrow-annotations/build.gradle
+++ b/arrow-annotations/build.gradle
@@ -7,6 +7,5 @@ apply from: "$SUB_PROJECT"
 apply from: "$DOC_CREATION"
 
 dependencies {
-    api "org.jetbrains.kotlin:kotlin-stdlib:$KOTLIN_VERSION"
     api "io.kindedj:kindedj:$KINDEDJ_VERSION"
 }
diff --git a/arrow-core-data/build.gradle b/arrow-core-data/build.gradle
index 2e1010070..bd20d6457 100644
--- a/arrow-core-data/build.gradle
+++ b/arrow-core-data/build.gradle
@@ -10,15 +10,14 @@ apply from: "$SUB_PROJECT"
 apply from: "$DOC_CREATION"
 
 dependencies {
-    compileOnly "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$KOTLIN_VERSION"
     api project(":arrow-annotations")
     kapt project(":arrow-meta")
     kaptTest project(":arrow-meta")
     compileOnly project(":arrow-meta")
     testCompileOnly project(":arrow-meta")
-    testRuntimeOnly "org.junit.vintage:junit-vintage-engine:$JUNIT_VINTAGE_VERSION"
-    testImplementation project(":arrow-core-test")
     testCompileOnly project(":arrow-syntax")
     testCompileOnly project(":arrow-core")
+    testRuntimeOnly "org.junit.vintage:junit-vintage-engine:$JUNIT_VINTAGE_VERSION"
+    testImplementation project(":arrow-core-test")
     testImplementation "io.arrow-kt:arrow-mtl-data:$VERSION_NAME"
 }
diff --git a/arrow-core-retrofit/build.gradle b/arrow-core-retrofit/build.gradle
index 8c5c267d5..34e1da380 100644
--- a/arrow-core-retrofit/build.gradle
+++ b/arrow-core-retrofit/build.gradle
@@ -8,11 +8,10 @@ apply from: "$DOC_CREATION"
 
 dependencies {
     compileOnly project(":arrow-core-data")
-    compileOnly "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$KOTLIN_VERSION"
     compileOnly "com.squareup.retrofit2:retrofit:$RETROFIT_VERSION"
-    testImplementation project(":arrow-core-test")
+    testCompileOnly "org.jetbrains.kotlin:kotlin-reflect:$KOTLIN_VERSION"
     testRuntimeOnly "org.junit.vintage:junit-vintage-engine:$JUNIT_VINTAGE_VERSION"
-    testCompileOnly "io.kotlintest:kotlintest-runner-junit5:$KOTLIN_TEST_VERSION", excludeArrow
+    testImplementation project(":arrow-core-test")
     testImplementation "com.squareup.retrofit2:converter-gson:$RETROFIT_VERSION"
     testImplementation "com.squareup.okhttp3:mockwebserver:$MOCKWEBSERVER_VERSION"
 }
diff --git a/arrow-core-test/build.gradle b/arrow-core-test/build.gradle
index 71ddfc2a0..c05b52eec 100644
--- a/arrow-core-test/build.gradle
+++ b/arrow-core-test/build.gradle
@@ -9,7 +9,6 @@ apply from: "$SUB_PROJECT"
 dependencies {
     api project(":arrow-core")
     api project(":arrow-core-data")
-    compileOnly "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$KOTLIN_VERSION"
     api "org.jetbrains.kotlinx:kotlinx-coroutines-core:$KOTLINX_COROUTINES_VERSION"
     api "io.kotlintest:kotlintest-runner-junit5:$KOTLIN_TEST_VERSION", excludeArrow
     testRuntimeOnly "org.junit.vintage:junit-vintage-engine:$JUNIT_VINTAGE_VERSION"
diff --git a/arrow-core/build.gradle b/arrow-core/build.gradle
index 2fe6f7086..874037fdd 100644
--- a/arrow-core/build.gradle
+++ b/arrow-core/build.gradle
@@ -8,13 +8,12 @@ apply from: "$SUB_PROJECT"
 apply from: "$DOC_CREATION"
 
 dependencies {
-    compileOnly "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$KOTLIN_VERSION"
     compileOnly project(":arrow-annotations")
     api project(":arrow-core-data")
     kapt project(":arrow-meta")
     kaptTest project(":arrow-meta")
     compileOnly project(":arrow-meta")
     testCompileOnly project(":arrow-meta")
-    testRuntimeOnly "org.junit.vintage:junit-vintage-engine:$JUNIT_VINTAGE_VERSION"
     testCompileOnly project(":arrow-core-test")
+    testRuntimeOnly "org.junit.vintage:junit-vintage-engine:$JUNIT_VINTAGE_VERSION"
 }
diff --git a/arrow-core/src/main/kotlin/arrow/core/extensions/tuple.kt b/arrow-core/src/main/kotlin/arrow/core/extensions/tuple.kt
index 5282dadd1..e4c2d3151 100644
--- a/arrow-core/src/main/kotlin/arrow/core/extensions/tuple.kt
+++ b/arrow-core/src/main/kotlin/arrow/core/extensions/tuple.kt
@@ -91,7 +91,7 @@ interface Tuple2Monad<F> : Monad<Tuple2PartialOf<F>>, Tuple2Applicative<F> {
   override fun <A, B> Tuple2Of<F, A>.flatMap(f: (A) -> Tuple2Of<F, B>) =
     fix().flatMap { f(it).fix() }
 
-  override tailrec fun <A, B> tailRecM(a: A, f: (A) -> Tuple2Of<F, Either<A, B>>): Tuple2<F, B> {
+  override fun <A, B> tailRecM(a: A, f: (A) -> Tuple2Of<F, Either<A, B>>): Tuple2<F, B> {
     val b = f(a).fix().b
     return when (b) {
       is Left -> tailRecM(b.a, f)
diff --git a/arrow-meta/arrow-meta-test-models/build.gradle b/arrow-meta/arrow-meta-test-models/build.gradle
index 3f4f59d79..5adf5052b 100644
--- a/arrow-meta/arrow-meta-test-models/build.gradle
+++ b/arrow-meta/arrow-meta-test-models/build.gradle
@@ -7,7 +7,6 @@ plugins {
 apply from: "$DOC_CREATION"
 
 dependencies {
-    compileOnly "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$KOTLIN_VERSION"
     compileOnly "com.google.auto.service:auto-service:$GOOGLE_AUTO_SERVICE_VERSION"
     kapt "com.google.auto.service:auto-service:$GOOGLE_AUTO_SERVICE_VERSION"
     compileOnly project(":arrow-annotations")
diff --git a/arrow-meta/build.gradle b/arrow-meta/build.gradle
index 837af65fb..d8ec5dc09 100644
--- a/arrow-meta/build.gradle
+++ b/arrow-meta/build.gradle
@@ -10,9 +10,8 @@ apply from: "$SUB_PROJECT"
 apply from: "$DOC_CREATION"
 
 dependencies {
-    compileOnly "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$KOTLIN_VERSION"
     api project(':arrow-annotations')
-    api "me.eugeniomarletti.kotlin.metadata:kotlin-metadata:$KOTLIN_METADATA_VERSION"
+    api "io.arrow-kt:kotlin-metadata:$KOTLIN_METADATA_VERSION"
     api("com.squareup:kotlinpoet:$KOTLIN_POET_VERSION") {
         exclude group: 'org.jetbrains.kotlin', module: 'kotlin-reflect'
     }
diff --git a/arrow-meta/src/main/java/arrow/common/utils/AbstractProcessor.kt b/arrow-meta/src/main/java/arrow/common/utils/AbstractProcessor.kt
index 8287858fa..b0f4d8cd8 100644
--- a/arrow-meta/src/main/java/arrow/common/utils/AbstractProcessor.kt
+++ b/arrow-meta/src/main/java/arrow/common/utils/AbstractProcessor.kt
@@ -31,7 +31,7 @@ abstract class AbstractProcessor : KotlinAbstractProcessor(), ProcessorUtils, Ko
     locationName()
       .replacePackageSeparatorsToFolderSeparators()
       .replaceInvalidPathCharacters()
-      .let { "$userDir/build/kdocs/meta/$it.javadoc" }
+      .let { "$tmpDir/build/kdocs/meta/$it.javadoc" }
       .let(::File)
 
   fun Element.kDoc(): String? =
@@ -50,8 +50,8 @@ abstract class AbstractProcessor : KotlinAbstractProcessor(), ProcessorUtils, Ko
   private fun processElementDoc(e: Element) {
     try {
       val doc = elementUtils.getDocComment(e)
-      val kDocLocation = e.kDocLocation()
       if (doc != null && doc.trim { it <= ' ' }.isNotEmpty()) {
+        val kDocLocation = e.kDocLocation()
         @Suppress("SwallowedException")
         try {
           val path = kDocLocation.toPath()
@@ -62,12 +62,7 @@ abstract class AbstractProcessor : KotlinAbstractProcessor(), ProcessorUtils, Ko
           }
           @Suppress("SwallowedException")
           try {
-            Files.delete(path)
-          } catch (e: IOException) {
-          }
-          @Suppress("SwallowedException")
-          try {
-            Files.createFile(path)
+            kDocLocation.createNewFile()
           } catch (e: IOException) {
           }
           kDocLocation.writeText(doc)
@@ -120,7 +115,7 @@ abstract class AbstractProcessor : KotlinAbstractProcessor(), ProcessorUtils, Ko
   protected abstract fun onProcess(annotations: Set<TypeElement>, roundEnv: RoundEnvironment)
 }
 
-private val userDir get() = System.getProperty("user.dir")
+private val tmpDir get() = System.getProperty("java.io.tmpdir")
 private fun String.replacePackageSeparatorsToFolderSeparators() = replace('.', '/')
 private fun String.replaceInvalidPathCharacters() = replace('?', '_')
 
diff --git a/arrow-meta/src/main/java/arrow/core/extensions/ExtensionProcessor.kt b/arrow-meta/src/main/java/arrow/core/extensions/ExtensionProcessor.kt
index 94e0241fb..6d6bec288 100644
--- a/arrow-meta/src/main/java/arrow/core/extensions/ExtensionProcessor.kt
+++ b/arrow-meta/src/main/java/arrow/core/extensions/ExtensionProcessor.kt
@@ -1,6 +1,5 @@
 package arrow.core.extensions
 
-import arrow.common.messager.log
 import arrow.common.utils.knownError
 import arrow.extension
 import arrow.meta.ast.Code
@@ -24,7 +23,7 @@ class ExtensionProcessor : MetaProcessor<extension>(extension::class), PolyTempl
     when (annotatedElement) {
       is AnnotatedElement.Interface -> {
         val info = annotatedElement.typeElement.typeClassInstance()
-        log("[${info?.instance?.name?.simpleName}] : Generating [${info?.typeClass?.name?.simpleName}] extensions for [${info?.projectedCompanion}]")
+        // log("[${info?.instance?.name?.simpleName}] : Generating [${info?.typeClass?.name?.simpleName}] extensions for [${info?.projectedCompanion}]")
         val fileSpec = annotatedElement.fileSpecBuilder(info)
         info.processTypeClassExtensions(fileSpec, annotatedElement)
       }
diff --git a/arrow-meta/src/main/java/arrow/meta/decoder/Decoder.kt b/arrow-meta/src/main/java/arrow/meta/decoder/Decoder.kt
index c54a904dc..1fe2f2000 100644
--- a/arrow-meta/src/main/java/arrow/meta/decoder/Decoder.kt
+++ b/arrow-meta/src/main/java/arrow/meta/decoder/Decoder.kt
@@ -79,7 +79,7 @@ interface TypeDecoder : MetaDecoder<Type> {
     val builder = ParameterSpec.builder(
       name = name,
       type = type.lyrics(),
-      modifiers = *modifiers.map { it.lyrics() }.toTypedArray()
+      modifiers = modifiers.map { it.lyrics() }.toTypedArray()
     )
     val builderDefaultValue = if (defaultValue != null) builder.defaultValue(defaultValue.lyrics()) else builder
     return builderDefaultValue.build()
@@ -203,7 +203,7 @@ interface TypeDecoder : MetaDecoder<Type> {
   fun TypeName.FunctionLiteral.lyrics(): com.squareup.kotlinpoet.TypeName =
     LambdaTypeName.get(
       receiver = receiverType?.lyrics(),
-      parameters = *parameters.map { it.lyrics() }.toTypedArray(),
+      parameters = parameters.map { it.lyrics() }.toTypedArray(),
       returnType = returnType.lyrics()
     ).copy(suspending = modifiers.contains(Modifier.Suspend))
 
diff --git a/arrow-meta/src/main/java/arrow/meta/encoder/jvm/TypeElementEncoder.kt b/arrow-meta/src/main/java/arrow/meta/encoder/jvm/TypeElementEncoder.kt
index 30b1d26fc..1c3e509d3 100644
--- a/arrow-meta/src/main/java/arrow/meta/encoder/jvm/TypeElementEncoder.kt
+++ b/arrow-meta/src/main/java/arrow/meta/encoder/jvm/TypeElementEncoder.kt
@@ -83,8 +83,8 @@ interface TypeElementEncoder : KotlinMetatadataEncoder, KotlinPoetEncoder, Proce
               val typeElement = this@type as TypeElement
               val classBuilder = Type(PackageName(pckgName), asType().asTypeName().toMeta(), Type.Shape.Class)
               val declaredConstructorSignatures = meta.constructorList.map { it.getJvmConstructorSignature(meta.nameResolver, meta.classProto.typeTable) }
-              val constructors = ElementFilter.constructorsIn(elementUtils.getAllMembers(this@type)).filter {
-                declaredConstructorSignatures.contains(it.jvmMethodSignature)
+              val constructors = ElementFilter.constructorsIn(elementUtils.getAllMembers(this@type)).filter { executableElement ->
+                declaredConstructorSignatures.any { it?.asString() == executableElement.jvmMethodSignature }
               }.mapNotNull { it.asConstructor(this@type) }
               Either.Right(classBuilder.copy(
                 primaryConstructor = constructors.find { it.first }?.second,
@@ -156,8 +156,8 @@ interface TypeElementEncoder : KotlinMetatadataEncoder, KotlinPoetEncoder, Proce
 
   fun TypeElement.declaredFunctions(declaredElement: TypeElement): List<Func> {
     val declaredFunctionSignatures = meta.functionList.map { it.getJvmMethodSignature(meta.nameResolver, meta.classProto.typeTable) }
-    return allFunctions(declaredElement).filter {
-      declaredFunctionSignatures.contains(it.jvmMethodSignature)
+    return allFunctions(declaredElement).filter { function ->
+      declaredFunctionSignatures.any { it?.asString() == function.jvmMethodSignature }
     }
   }
 
@@ -308,7 +308,7 @@ interface TypeElementEncoder : KotlinMetatadataEncoder, KotlinPoetEncoder, Proce
       }
       val members = filteredMembers.mapNotNull { member ->
         val templateFunction = allFunctions.find { (proto, function) ->
-          function.getJvmMethodSignature(proto.nameResolver, proto.classProto.typeTable) == member.jvmMethodSignature
+          function.getJvmMethodSignature(proto.nameResolver, proto.classProto.typeTable)?.asString() == member.jvmMethodSignature
         }
         @Suppress("SwallowedException")
         try {
@@ -386,7 +386,7 @@ interface TypeElementEncoder : KotlinMetatadataEncoder, KotlinPoetEncoder, Proce
   fun ExecutableElement.asConstructor(typeElement: TypeElement): Pair<Boolean, Func>? =
     kotlinMetadataUtils().run {
       typeElement.meta.constructorList.find {
-        it.getJvmConstructorSignature(typeElement.meta.nameResolver, typeElement.meta.classProto.typeTable) == this@asConstructor.jvmMethodSignature
+        it.getJvmConstructorSignature(typeElement.meta.nameResolver, typeElement.meta.classProto.typeTable)?.asString() == this@asConstructor.jvmMethodSignature
       }?.let { constructor ->
         constructor.isPrimary to
           Func(
diff --git a/arrow-meta/src/test/java/arrow/ap/tests/APTest.kt b/arrow-meta/src/test/java/arrow/ap/tests/APTest.kt
index e73a6bfb1..dc2693f3c 100644
--- a/arrow-meta/src/test/java/arrow/ap/tests/APTest.kt
+++ b/arrow-meta/src/test/java/arrow/ap/tests/APTest.kt
@@ -1,7 +1,5 @@
 package arrow.ap.tests
 
-import com.google.common.collect.ImmutableList
-import com.google.common.io.Files
 import com.google.testing.compile.CompilationSubject.assertThat
 import com.google.testing.compile.Compiler.javac
 import com.google.testing.compile.JavaFileObjects
@@ -17,7 +15,7 @@ abstract class APTest(
 
   fun testProcessor(
     vararg processor: AnnotationProcessor,
-    generationDir: File = Files.createTempDir(),
+    generationDir: File = createTempDir(),
     actualFileLocation: (File) -> String = { it.path }
   ) {
 
@@ -40,7 +38,7 @@ abstract class APTest(
 
         val compilation = javac()
           .withProcessors(proc)
-          .withOptions(ImmutableList.of("-Akapt.kotlin.generated=$generationDir", "-proc:only"))
+          .withOptions(listOf("-Akapt.kotlin.generated=$generationDir", "-proc:only"))
           .compile(sources.map {
             val stub = File(stubs, it).toURI().toURL()
             JavaFileObjects.forResource(stub)
diff --git a/arrow-syntax/build.gradle b/arrow-syntax/build.gradle
index 889f8194f..69ce674aa 100644
--- a/arrow-syntax/build.gradle
+++ b/arrow-syntax/build.gradle
@@ -7,9 +7,9 @@ apply from: "$SUB_PROJECT"
 apply from: "$DOC_CREATION"
 
 dependencies {
-    compileOnly "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$KOTLIN_VERSION"
     api project(":arrow-annotations")
     api project(":arrow-core")
+    testCompileOnly "org.jetbrains.kotlin:kotlin-reflect:$KOTLIN_VERSION"
     testRuntimeOnly "org.junit.vintage:junit-vintage-engine:$JUNIT_VINTAGE_VERSION"
     testImplementation project(":arrow-core-test")
 }
diff --git a/build.gradle b/build.gradle
index 83c36eb9f..80c424e55 100644
--- a/build.gradle
+++ b/build.gradle
@@ -35,6 +35,7 @@ configure(subprojects
 
     animalsniffer { // Ingore tests
         sourceSets = [sourceSets.main]
+        ignore 'java.lang.*'
     }
     dependencies {
         compileOnly "org.codehaus.mojo:animal-sniffer-annotations:1.19"
diff --git a/gradle.properties b/gradle.properties
index 9b33264e8..487e18915 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -18,5 +18,5 @@ kapt.incremental.apt=true
 
 # Versions just related to arrow-core
 GOOGLE_AUTO_SERVICE_VERSION=1.0-rc7
-GOOGLE_COMPILE_TESTING_VERSION=0.15
+GOOGLE_COMPILE_TESTING_VERSION=0.18
 KOTLIN_POET_VERSION=1.5.0