Miscellaneous Scala cleanup (#1006)

This PR makes a couple quick changes analogous to
runtimeverification/k#4055:

- Update `scala-maven-plugin` to its latest version
- Set the Java version by relying on `<release>` in
`maven-compiler-plugin` inherited from the parent POM, rather than
manually setting `-source` and `-target` for `javac`
- Disable various Scala language extensions and enable `-Werror`
  - One warning about pattern matching on an erased type
- Remaining warnings were exhaustiveness issues fixed with a `case _ =>
???`. This is poor style and an abuse of `???` IMO, but it's already
pervasive throughout our codebase.

---------

Co-authored-by: Bruce Collie <brucecollie82@gmail.com>

matching/pom.xml

@@ -75,22 +75,26 @@
       <version>1.4</version>
       <classifier>linux64</classifier>
     </dependency>
+    <dependency>
+      <groupId>org.scala-sbt</groupId>
+      <artifactId>compiler-bridge_2.12</artifactId>
+      <version>1.8.0</version>
+    </dependency>
   </dependencies>
 
   <build>
     <plugins>
       <plugin>
         <artifactId>maven-compiler-plugin</artifactId>
-        <version>3.7.0</version>
+        <version>3.12.1</version>
         <configuration>
-          <source>${java.version}</source>
-          <target>${java.version}</target>
+          <release>${java.version}</release>
         </configuration>
       </plugin>
       <plugin>
         <groupId>net.alchim31.maven</groupId>
         <artifactId>scala-maven-plugin</artifactId>
-        <version>3.3.1</version>
+        <version>4.8.1</version>
         <executions>
           <execution>
             <id>scala-compile-first</id>
@@ -110,18 +114,10 @@
         </executions>
         <configuration>
           <args>
-            <arg>-Xexperimental</arg>
+            <arg>-Werror</arg>
             <arg>-feature</arg>
             <arg>-deprecation</arg>
-            <arg>-language:implicitConversions</arg>
-            <arg>-language:postfixOps</arg>
           </args>
-	  <javacArgs>
-            <javacArg>-source</javacArg>
-            <javacArg>${java.version}</javacArg>
-            <javacArg>-target</javacArg>
-            <javacArg>${java.version}</javacArg>
-          </javacArgs>
         </configuration>
       </plugin>
       <plugin>

matching/src/main/scala/org/kframework/backend/llvm/matching/Constructor.scala

@@ -19,6 +19,7 @@ case class Empty() extends Constructor {
     f.sortInfo.category match {
       case SetS() => SetP(Seq(), None, symbol, SymbolP(symbol, Seq()))
       case MapS() => MapP(Seq(), Seq(), None, symbol, SymbolP(symbol, Seq()))
+      case _      => ???
     }
   }
   override lazy val hashCode: Int = scala.runtime.ScalaRunTime._hashCode(this)
@@ -118,6 +119,7 @@ case class HasKey(isSet: Boolean, element: SymbolOrAlias, key: Option[Pattern[Op
             concat(element(key, value), child)
           )
         }
+      case _ => ???
     }
   }
   override lazy val hashCode: Int = scala.runtime.ScalaRunTime._hashCode(this)
@@ -166,6 +168,7 @@ case class HasNoKey(isSet: Boolean, key: Option[Pattern[Option[Occurrence]]]) ex
             concat(element(wildcard, wildcard), child)
           )
         }
+      case _ => ???
     }
   }
   override lazy val hashCode: Int = scala.runtime.ScalaRunTime._hashCode(this)

matching/src/main/scala/org/kframework/backend/llvm/matching/Matrix.scala

@@ -781,18 +781,20 @@ class Matrix private (
         )
     }
     // fill out the bindings for list range variables
-    val withRanges = row.clause.listRanges.foldRight(sc) { case ((o @ Num(_, o2), hd, tl), dt) =>
-      Function(
-        "hook_LIST_range_long",
-        o,
-        Seq(
-          (o2, "LIST.List"),
-          (Lit(hd.toString, "MINT.MInt 64"), "MINT.MInt 64"),
-          (Lit(tl.toString, "MINT.MInt 64"), "MINT.MInt 64")
-        ),
-        "LIST.List",
-        dt
-      )
+    val withRanges = row.clause.listRanges.foldRight(sc) {
+      case ((o @ Num(_, o2), hd, tl), dt) =>
+        Function(
+          "hook_LIST_range_long",
+          o,
+          Seq(
+            (o2, "LIST.List"),
+            (Lit(hd.toString, "MINT.MInt 64"), "MINT.MInt 64"),
+            (Lit(tl.toString, "MINT.MInt 64"), "MINT.MInt 64")
+          ),
+          "LIST.List",
+          dt
+        )
+      case _ => ???
     }
     val withOverloads = row.clause.overloadChildren.foldRight(withRanges) {
       case ((SymbolC(inj), f, v), dt) =>
@@ -810,6 +812,7 @@ class Matrix private (
           ),
           dt
         )
+      case _ => ???
     }
     val withSpecials = row.clause.specializedVars.foldRight(withOverloads) { case ((o, p), dt) =>
       MakePattern(o, p._1.hookAtt, p._2, dt)

matching/src/main/scala/org/kframework/backend/llvm/matching/Parser.scala

@@ -429,6 +429,7 @@ object Parser {
 
   val heuristicMap: Map[Char, Heuristic] = {
     import scala.reflect.runtime.universe
+    import universe.LiteralTag
 
     val heuristicType        = universe.typeOf[Heuristic]
     val heuristicClass       = heuristicType.typeSymbol.asClass

matching/src/main/scala/org/kframework/backend/llvm/matching/pattern/Pattern.scala

@@ -4,7 +4,6 @@ import com.runtimeverification.k.kore
 import com.runtimeverification.k.kore.implementation.{ DefaultBuilders => B }
 import com.runtimeverification.k.kore.SymbolOrAlias
 import org.kframework.backend.llvm.matching._
-import scala.math.min
 
 sealed trait Pattern[T] {
   def signature(clause: Clause): Seq[Constructor]
@@ -365,6 +364,7 @@ case class MapP[T] private (
       case (HasNoKey(_, Some(p)), _)  => !keys.map(_.canonicalize(clause)).contains(p)
       case (HasKey(_, _, None), None) => keys.nonEmpty && clause.action.priority <= maxPriority
       case (HasNoKey(_, None), _)     => keys.nonEmpty && clause.action.priority > maxPriority
+      case _                          => ???
     }
   def score(
       h: Heuristic,
@@ -419,6 +419,7 @@ case class MapP[T] private (
         } else {
           Seq(keys.head, values.head, MapP(keys.tail, values.tail, frame, ctr, orig))
         }
+      case _ => ???
     }
   def expandOr: Seq[Pattern[T]] = {
     val withKeys = keys.indices.foldLeft(Seq(this))((accum, ix) =>
@@ -593,6 +594,7 @@ case class SetP[T] private (
       case (HasNoKey(_, Some(p)), _)  => !elements.map(_.canonicalize(clause)).contains(p)
       case (HasKey(_, _, None), None) => elements.nonEmpty && clause.action.priority <= maxPriority
       case (HasNoKey(_, None), _)     => elements.nonEmpty && clause.action.priority > maxPriority
+      case _                          => ???
     }
   def score(
       h: Heuristic,
@@ -640,6 +642,7 @@ case class SetP[T] private (
         } else {
           Seq(elements.head, SetP(elements.tail, frame, ctr, orig))
         }
+      case _ => ???
     }
   def expandOr: Seq[Pattern[T]] = {
     val withElements = elements.indices.foldLeft(Seq(this))((accum, ix) =>

matching/src/main/scala/org/kframework/backend/llvm/matching/pattern/SortCategory.scala

@@ -49,6 +49,7 @@ object SortCategory {
           MatchingException.Type.COMPILER_ERROR,
           "LLVM Backend does not support multisets. If you are seeing this error due to a configuration cell tagged with multiplicity=\"*\", please add either type=\"Map\" or type=\"Set\". If you still need the collection to not contain duplicates, it is recommended you also add a unique identifier each time a cell is created. You can do this with !X:Int."
         );
+      case _ => ???
     }
 
   private def getBitwidth(s: Sort, symlib: Parser.SymLib): Int =

nix/build-maven-package.nix

@@ -26,12 +26,13 @@ let
         mvn dependency:get -Dartifact="$artifactId" -Dmaven.repo.local=$out/.m2
       done
 
-      for artifactId in ${builtins.toString manualMvnSourceArtifacts}
+      for artifact in ${builtins.toString manualMvnSourceArtifacts}
       do
-        group=$(echo $artifactId | cut -d':' -f1)
-        artifact=$(echo $artifactId | cut -d':' -f2)
+        groupId=$(echo $artifact | cut -d':' -f1)
+        artifactId=$(echo $artifact | cut -d':' -f2)
+        version=$(echo $artifact | cut -d':' -f3)
         echo "downloading manual sources $artifactId"
-        mvn dependency:sources -DincludeGroupIds=$group -DincludeArtifactIds=$artifact -Dmaven.repo.local=$out/.m2
+        mvn dependency:get -Dclassifier=sources -DgroupId=$groupId -DartifactId=$artifactId -Dversion=$version -Dmaven.repo.local=$out/.m2
       done
     '' + lib.optionalString (!buildOffline) ''
       mvn package -Dmaven.repo.local=$out/.m2 ${mvnParameters}

nix/llvm-backend-matching.nix

@@ -12,11 +12,17 @@ let self = maven.buildMavenPackage rec {
       "org.apache.maven.plugins:maven-compiler-plugin:3.7.0"
     ];
 
+    manualMvnSourceArtifacts = [
+      "org.scala-sbt:compiler-bridge_2.12:1.8.0"
+    ];
+
     passthru = {
       jar =
         "${self}/share/java/llvm-backend-matching-1.0-SNAPSHOT-jar-with-dependencies.jar";
     };
 
+    mvnParameters = "-DsecondaryCacheDir=secondary-cache";
+
     installPhase = ''
       mkdir -p $out/share/java
       install -Dm644 target/*.jar $out/share/java

nix/overlay.nix

@@ -21,7 +21,7 @@ let
 
   llvm-backend-matching = import ./llvm-backend-matching.nix {
     src = prev.llvm-backend-matching-src;
-    mvnHash = "sha256-HF6BXeCnV5I7+oRVGK8DGHjaAtHWLfEaCwtkVcQHoGU";
+    mvnHash = "sha256-2X8G3T05Pk1apA0f04Mdu/8DAB89oB9XwTBQ3KVoc/A=";
     inherit (final) maven;
   };