Disable New Inference in JS backend

See #KT-37163 for details

compiler/cli/cli-js/src/org/jetbrains/kotlin/cli/js/JSLanguageVersionSettings.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.cli.js
+
+import org.jetbrains.kotlin.config.*
+
+class JSLanguageVersionSettings(private val delegate: LanguageVersionSettings) : LanguageVersionSettings {
+    companion object {
+        private val disabledFeatures = setOf(
+            LanguageFeature.NewInference,
+            LanguageFeature.FunctionalInterfaceConversion,
+            LanguageFeature.SamConversionForKotlinFunctions,
+            LanguageFeature.SamConversionPerArgument,
+            LanguageFeature.FunctionReferenceWithDefaultValueAsOtherType,
+            LanguageFeature.NonStrictOnlyInputTypesChecks
+        )
+    }
+
+    override fun getFeatureSupport(feature: LanguageFeature): LanguageFeature.State {
+        return if (feature in disabledFeatures)
+            LanguageFeature.State.DISABLED
+        else
+            delegate.getFeatureSupport(feature)
+    }
+
+    override fun isPreRelease(): Boolean = delegate.isPreRelease()
+
+    override fun <T> getFlag(flag: AnalysisFlag<T>): T = delegate.getFlag(flag)
+
+    override val apiVersion: ApiVersion
+        get() = delegate.apiVersion
+
+    override val languageVersion: LanguageVersion
+        get() = delegate.languageVersion
+}

compiler/cli/cli-js/src/org/jetbrains/kotlin/cli/js/K2JSCompiler.java

@@ -246,6 +246,13 @@ public class K2JSCompiler extends CLICompiler<K2JSCompilerArguments> {
 
         configuration.put(CommonConfigurationKeys.MODULE_NAME, FileUtil.getNameWithoutExtension(outputFile));
 
+        if (!arguments.getNewInference()) {
+            CommonConfigurationKeysKt.setLanguageVersionSettings(
+                    configuration,
+                    new JSLanguageVersionSettings(CommonConfigurationKeysKt.getLanguageVersionSettings(configuration))
+            );
+        }
+
         JsConfig config = new JsConfig(project, configuration);
         JsConfig.Reporter reporter = new JsConfig.Reporter() {
             @Override

compiler/cli/cli-js/src/org/jetbrains/kotlin/cli/js/K2JsIrCompiler.kt

@@ -24,10 +24,7 @@ import org.jetbrains.kotlin.cli.common.messages.MessageUtil
 import org.jetbrains.kotlin.cli.jvm.compiler.EnvironmentConfigFiles
 import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment
 import org.jetbrains.kotlin.cli.jvm.plugins.PluginCliParser
-import org.jetbrains.kotlin.config.CommonConfigurationKeys
-import org.jetbrains.kotlin.config.CompilerConfiguration
-import org.jetbrains.kotlin.config.IncrementalCompilation
-import org.jetbrains.kotlin.config.Services
+import org.jetbrains.kotlin.config.*
 import org.jetbrains.kotlin.incremental.components.ExpectActualTracker
 import org.jetbrains.kotlin.incremental.components.LookupTracker
 import org.jetbrains.kotlin.incremental.js.IncrementalDataProvider