Trying ZINC.

Doesn't work
Issues:
Biggest one is mess with classpath:
    Source compiling compiler_bridge
        NoSuchMethodError: 'scala.tools.nsc.settings.AbsSettings$AbsSetting scala.tools.nsc.Settings.nowarn()'
        davidB/scala-maven-plugin#363
        sbt/zinc#698
    Need uber jars in various forms (not hacked all the way through and where I gave up)
        Caused by: java.lang.ClassNotFoundException: jline.TerminalFactory
    Required adding ~40 dependencies of Zinc
    Conflicts with IJ scala plugin classes
        com.intellij.diagnostic.PluginException: Cannot load class scala.Option (
          error: loader constraint violation: loader com.intellij.ide.plugins.cl.PluginClassLoader @29446114 wants to load abstract class scala.Option. A different abstract class with the same name was previously loaded by com.intellij.ide.plugins.cl.PluginClassLoader @61ed07dc. (scala.Option is in unnamed module of loader com.intellij.ide.plugins.cl.PluginClassLoader @61ed07dc, parent loader 'bootstrap'),
          classLoader=PluginClassLoader(plugin=PluginDescriptor(name=Bazel, id=com.google.idea.bazel.ijwb, descriptorPath=plugin.xml, path=~/Library/Caches/JetBrains/IntelliJIdea2022.2/plugins-sandbox/plugins/ijwb, version=9999-api-version-222, package=null, isBundled=false), packagePrefix=null, instanceId=282, state=active)
        )
            at com.intellij.ide.plugins.cl.PluginClassLoader.loadClassInsideSelf(PluginClassLoader.java:411)

Smaller:
    Hack in how to find the jar of the fast scalac
    Hardcoding the scala version and the SDK
    No access for now to scalaCompilerPlugins, scalaCompilerOptions, javaCompilerOptions

Tech debt in the PR:
    Two compiler impls (fast_build_scalac2, ScalaCompilerImpl2)
    Especially in the BUILD files

WORKSPACE

@@ -199,7 +199,7 @@ http_archive(
 _SCALA_BUILD_FILE = """
 java_import(
     name = "scala",
-    jars = glob(["Scala/lib/*.jar"]),
+    jars = glob(["Scala/lib/*.jar"], exclude = ["Scala/lib/compiler-interface-1.6.1.jar"]),
     visibility = ["//visibility:public"],
 )
 """
@@ -568,3 +568,21 @@ buildbuddy_deps()
 load("@io_buildbuddy_buildbuddy_toolchain//:rules.bzl", "buildbuddy")
 
 buildbuddy(name = "buildbuddy_toolchain")
+
+load("//:zinc.bzl", zinc_deps = "dependencies")
+
+zinc_deps()
+
+_SRC_FILEGROUP_BUILD_FILE_CONTENT = """
+filegroup(
+    name = "src",
+    srcs = glob(["**/*.scala", "**/*.java"]),
+    visibility = ["//visibility:public"]
+)"""
+
+http_archive(
+    name = "compiler_bridge_2_12",
+    build_file_content = _SRC_FILEGROUP_BUILD_FILE_CONTENT,
+    sha256 = "24cd30dcb37c2b24f962118f49489c98a66b49600cfd7fbb9eab68475ddd56a2",
+    url = "https://repo.maven.apache.org/maven2/org/scala-sbt/compiler-bridge_2.12/1.3.4/compiler-bridge_2.12-1.3.4-sources.jar",
+)

ijwb/BUILD

@@ -121,12 +121,33 @@ repackaged_files(
     prefix = "ijwb/lib",
 )
 
+repackaged_files(
+    name = "fast_build_scalac2",
+    srcs = ["//scala:fast_build_scalac2_deploy.jar"],
+    prefix = "ijwb/lib",
+)
+
+repackaged_files(
+    name = "fast_build_scalac2_deps",
+    srcs = ["//scala:fast_build_scalac2_deps_deploy.jar"],
+    prefix = "ijwb/lib",
+)
+
+repackaged_files(
+    name = "compiler_bridge_2_12",
+    srcs = ["//scala:compiler_bridge_2_12"],
+    prefix = "ijwb/lib",
+)
+
 intellij_plugin_debug_target(
     name = "ijwb_bazel_dev",
     deps = [
         ":aspect_directory",
         ":fast_build_javac",
-        ":fast_build_scalac",
+        #        ":fast_build_scalac",
+        ":fast_build_scalac2",
+        ":fast_build_scalac2_deps",
+        ":compiler_bridge_2_12",
         ":plugin_jar",
     ],
 )
@@ -136,7 +157,10 @@ plugin_deploy_zip(
     srcs = [
         ":aspect_directory",
         ":fast_build_javac",
-        ":fast_build_scalac",
+        #        ":fast_build_scalac",
+        ":fast_build_scalac2",
+        ":fast_build_scalac2_deps",
+        ":compiler_bridge_2_12",
         ":plugin_jar",
     ],
     zip_filename = "ijwb_bazel.zip",

java/src/com/google/idea/blaze/java/fastbuild/FastBuildCompilerExtensionPoint.java

@@ -1,5 +1,6 @@
 package com.google.idea.blaze.java.fastbuild;
 
+import com.google.idea.blaze.base.command.info.BlazeInfo;
 import com.intellij.openapi.extensions.ExtensionPointName;
 
 import java.io.File;
@@ -10,6 +11,7 @@ public interface FastBuildCompilerExtensionPoint {
     ExtensionPointName<FastBuildCompilerExtensionPoint> EP_NAME =
             ExtensionPointName.create("com.google.idea.blaze.FastBuildCompilerExtensionPoint");
 
-    FastBuildCompiler getCompiler(List<File> javacJars, List<File> bootClassPathJars, String sourceVersion, String targetVersion);
+    FastBuildCompiler getCompiler(List<File> javacJars, List<File> bootClassPathJars, String sourceVersion, String targetVersion,
+        BlazeInfo blazeInfo);
 
 }

java/src/com/google/idea/blaze/java/fastbuild/FastBuildCompilerFactoryImpl.java

@@ -116,7 +116,7 @@ public FastBuildCompiler getCompilerFor(Label label, Map<Label, FastBuildBlazeDa
       // Hacky way to substitute FastBuildCompiler with Scala compiler
       // Calls com.google.idea.blaze.scala.fastbuild.FastBuildScalaCompilerExtensionPoint
       return FastBuildCompilerExtensionPoint.EP_NAME.getExtensions()[0]
-              .getCompiler(javacJars, bootJars, javaToolchain.sourceVersion(), javaToolchain.targetVersion());
+              .getCompiler(javacJars, bootJars, javaToolchain.sourceVersion(), javaToolchain.targetVersion(), projectData.getBlazeInfo());
     } else {
       Javac javac = createCompiler(javacJars);
       return new JavacRunner(

scala/BUILD

@@ -14,6 +14,10 @@ load(
     "//:build-visibility.bzl",
     "PLUGIN_PACKAGES_VISIBILITY",
 )
+load(
+    "@io_bazel_rules_scala//scala:scala.bzl",
+    "scala_library",
+)
 
 licenses(["notice"])
 
@@ -30,11 +34,15 @@ _FAST_BUILD_SCALAC_IMPL_SRCS = [
     "src/com/google/idea/blaze/scala/fastbuild/ScalaCompilerImpl.java",
 ]
 
+_FAST_BUILD_SCALAC_IMPL_SRCS2 = [
+    "src/com/google/idea/blaze/scala/fastbuild/ScalaCompilerImpl2.scala",
+]
+
 java_library(
     name = "scala",
     srcs = glob(
         ["src/**/*.java"],
-        exclude = _FAST_BUILD_SCALAC_SRCS + _FAST_BUILD_SCALAC_IMPL_SRCS
+        exclude = _FAST_BUILD_SCALAC_SRCS + _FAST_BUILD_SCALAC_IMPL_SRCS,
     ),
     visibility = ["//visibility:public"],
     deps = [
@@ -60,6 +68,61 @@ java_library(
     deps = [],
 )
 
+scala_library(
+    name = "fast_build_scalac2",
+    srcs = _FAST_BUILD_SCALAC_SRCS + _FAST_BUILD_SCALAC_IMPL_SRCS2,
+    visibility = [
+        "//aswb:__pkg__",
+        "//ijwb:__pkg__",
+        "//scala/com/google/devtools/intellij/blaze/plugin:__subpackages__",
+    ],
+    deps = [
+        "//base",
+        "@org_scala_sbt_compiler_interface",
+        "@org_scala_sbt_util_control_2_12",
+        "@org_scala_sbt_util_interface",
+        "@org_scala_sbt_util_logging_2_12",
+        "@org_scala_sbt_zinc_2_12",
+        "@org_scala_sbt_zinc_classpath_2_12",
+        "@org_scala_sbt_zinc_compile_core_2_12",
+        "@org_scala_sbt_zinc_core_2_12",
+    ],
+)
+
+scala_library(
+    name = "fast_build_scalac2_deps",
+    srcs = [],
+    visibility = [
+        "//aswb:__pkg__",
+        "//ijwb:__pkg__",
+        "//scala/com/google/devtools/intellij/blaze/plugin:__subpackages__",
+    ],
+    deps = [
+        "@org_scala_sbt_compiler_interface",
+        "@org_scala_sbt_util_control_2_12",
+        "@org_scala_sbt_util_interface",
+        "@org_scala_sbt_util_logging_2_12",
+        "@org_scala_sbt_zinc_2_12",
+        "@org_scala_sbt_zinc_classpath_2_12",
+        "@org_scala_sbt_zinc_compile_core_2_12",
+        "@org_scala_sbt_zinc_core_2_12",
+    ],
+)
+
+scala_library(
+    name = "compiler_bridge_2_12",
+    srcs = [
+        "@compiler_bridge_2_12//:src",
+    ],
+    visibility = ["//visibility:public"],
+    deps = [
+        "@org_scala_lang_scala_compiler",
+        "@org_scala_lang_scala_library",
+        "@org_scala_lang_scala_reflect",
+        "@org_scala_sbt_compiler_interface",
+        "@org_scala_sbt_util_interface",
+    ],
+)
 optional_plugin_xml(
     name = "optional_xml",
     module = "org.intellij.scala",