Address new warnings with the strict patmat exhaustivity of 2.13.4.

In 2.13.4, the pattern match exhaustivity analysis has become much stricter. It remains active in the presence of non-sealed classes, guards, and custom extractors. This change causes a lot of new warnings in our codebase. See scala/scala#9140 We address most warnings with `@unchecked`, but for some we throw more specialized exceptions instead.
sjrd · Nov 2, 2020 · cf8c9d1 · cf8c9d1
1 parent aa81c35
commit cf8c9d1
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Showing 23 changed files with 98 additions and 50 deletions.
diff --git a/compiler/src/main/scala/org/scalajs/nscplugin/GenJSCode.scala b/compiler/src/main/scala/org/scalajs/nscplugin/GenJSCode.scala
@@ -273,9 +273,10 @@ abstract class GenJSCode[G <: Global with Singleton](val global: G)
       try {
         def collectClassDefs(tree: Tree): List[ClassDef] = {
           tree match {
-            case EmptyTree => Nil
-            case PackageDef(_, stats) => stats flatMap collectClassDefs
-            case cd: ClassDef => cd :: Nil
+            case EmptyTree            => Nil
+            case PackageDef(_, stats) => stats.flatMap(collectClassDefs)
+            case cd: ClassDef         => cd :: Nil
+            case _                    => abort(s"Unexpected top-level tree at ${tree.pos}:\n$tree")
           }
         }
         val allClassDefs = collectClassDefs(cunit.body)
@@ -1652,6 +1653,8 @@ abstract class GenJSCode[G <: Global with Singleton](val global: G)
             (Nil, applyCtor)
           case js.Block(prepStats :+ (applyCtor: js.ApplyStatic)) =>
             (prepStats, applyCtor)
+          case _ =>
+            abort(s"Unexpected body for JS constructor dispatch resolution at ${body.pos}:\n$body")
         }
         val js.ApplyStatic(_, _, js.MethodIdent(ctorName), js.This() :: ctorArgs) =
           applyCtor
@@ -1731,6 +1734,9 @@ abstract class GenJSCode[G <: Global with Singleton](val global: G)
                 if method.name.isConstructor =>
               method.name
           }.get
+
+        case _ =>
+          abort(s"Unexpected secondary constructor body at ${tree.pos}:\n$tree")
       }
 
       val (primaryCtor :: Nil, secondaryCtors) = ctors.partition {
@@ -2759,6 +2765,8 @@ abstract class GenJSCode[G <: Global with Singleton](val global: G)
             true
           case pat @ Bind(_, _) =>
             isMaybeJavaScriptException(pat.symbol.tpe)
+          case pat =>
+            abort(s"Unexpected pattern at ${pat.pos}: $pat")
         }
       }
 
@@ -2791,6 +2799,8 @@ abstract class GenJSCode[G <: Global with Singleton](val global: G)
             val ident = encodeLocalSym(pat.symbol)
             val origName = originalNameOfLocal(pat.symbol)
             (pat.symbol.tpe, Some((ident, origName)))
+          case _ =>
+            abort(s"Unexpected pattern at ${pat.pos}: $pat")
         })
 
         // Generate the body that must be executed if the exception matches
@@ -5200,7 +5210,7 @@ abstract class GenJSCode[G <: Global with Singleton](val global: G)
           } else if (jsInterop.isJSBracketAccess(sym)) {
             assert(argc == 1 || argc == 2,
                 s"@JSBracketAccess methods should have 1 or 2 non-varargs arguments")
-            argsNoSpread match {
+            (argsNoSpread: @unchecked) match {
               case List(keyArg) =>
                 genSelectGet(keyArg)
               case List(keyArg, valueArg) =>
@@ -6418,7 +6428,10 @@ abstract class GenJSCode[G <: Global with Singleton](val global: G)
       import jsPrimitives._
       if (isPrimitive(sym)) {
         getPrimitive(sym) match {
-          case UNITVAL => js.Undefined()
+          case UNITVAL =>
+            js.Undefined()
+          case _ =>
+            abort(s"Unexpected primitive in genStaticField at $pos: ${sym.fullName}")
         }
       } else {
         val className = encodeClassName(sym.owner)

diff --git a/compiler/src/main/scala/org/scalajs/nscplugin/PrepJSInterop.scala b/compiler/src/main/scala/org/scalajs/nscplugin/PrepJSInterop.scala
@@ -166,7 +166,8 @@ abstract class PrepJSInterop[G <: Global with Singleton](val global: G)
 
       checkJSNameAnnots(sym)
 
-      val transformedTree: Tree = tree match {
+      // @unchecked needed on 2.13.4+ because MemberDef is not marked `sealed`
+      val transformedTree: Tree = (tree: @unchecked) match {
         case tree: ImplDef =>
           if (shouldPrepareExports)
             registerClassOrModuleExports(sym)
@@ -828,6 +829,9 @@ abstract class PrepJSInterop[G <: Global with Singleton](val global: G)
             }
             Some(loadSpec)
 
+          case Some(annot) =>
+            abort(s"checkAndGetJSNativeLoadingSpecAnnotOf returned unexpected annotation $annot")
+
           case None =>
             /* We already emitted an error. Invent something not to cause
              * cascading errors.

diff --git a/ir/src/main/scala/org/scalajs/ir/Trees.scala b/ir/src/main/scala/org/scalajs/ir/Trees.scala
@@ -1235,7 +1235,7 @@ object Trees {
 
     def isConstructor: Boolean = (ordinal & ConstructorFlag) != 0
 
-    def prefixString: String = this match {
+    def prefixString: String = (this: @unchecked) match {
       case Public            => ""
       case Private           => "private "
       case PublicStatic      => "static "

diff --git a/javalib/src/main/scala/java/math/BigDecimal.scala b/javalib/src/main/scala/java/math/BigDecimal.scala
@@ -222,7 +222,7 @@ object BigDecimal {
     val absFraction = Math.abs(fraction)
     val sigFraction = java.lang.Integer.signum(fraction)
     // the carry after rounding
-    roundingMode match {
+    (roundingMode: @unchecked) match {
       case UP          => sigFraction
       case DOWN        => 0
       case CEILING     => Math.max(sigFraction, 0)

diff --git a/javalib/src/main/scala/java/nio/charset/CharsetDecoder.scala b/javalib/src/main/scala/java/nio/charset/CharsetDecoder.scala
@@ -116,7 +116,7 @@ abstract class CharsetDecoder protected (cs: Charset,
           if (result2.isUnmappable()) unmappableCharacterAction()
           else malformedInputAction()
 
-        action match {
+        (action: @unchecked) match {
           case CodingErrorAction.REPLACE =>
             if (out.remaining() < replacement().length) {
               CoderResult.OVERFLOW

diff --git a/javalib/src/main/scala/java/nio/charset/CharsetEncoder.scala b/javalib/src/main/scala/java/nio/charset/CharsetEncoder.scala
@@ -139,7 +139,7 @@ abstract class CharsetEncoder protected (cs: Charset,
           if (result2.isUnmappable()) unmappableCharacterAction()
           else malformedInputAction()
 
-        action match {
+        (action: @unchecked) match {
           case CodingErrorAction.REPLACE =>
             if (out.remaining() < replacement().length) {
               CoderResult.OVERFLOW

diff --git a/linker-interface/shared/src/main/scala/org/scalajs/linker/interface/ModuleKind.scala b/linker-interface/shared/src/main/scala/org/scalajs/linker/interface/ModuleKind.scala
@@ -53,7 +53,7 @@ object ModuleKind {
       extends Fingerprint[ModuleKind] {
 
     override def fingerprint(moduleKind: ModuleKind): String = {
-      moduleKind match {
+      (moduleKind: @unchecked) match {
         case NoModule       => "NoModule"
         case ESModule       => "ESModule"
         case CommonJSModule => "CommonJSModule"

diff --git a/linker-interface/shared/src/main/scala/org/scalajs/linker/interface/ModuleSplitStyle.scala b/linker-interface/shared/src/main/scala/org/scalajs/linker/interface/ModuleSplitStyle.scala
@@ -31,7 +31,7 @@ object ModuleSplitStyle {
       extends Fingerprint[ModuleSplitStyle] {
 
     override def fingerprint(moduleSplitStyle: ModuleSplitStyle): String = {
-      moduleSplitStyle match {
+      (moduleSplitStyle: @unchecked) match {
         case FewestModules   => "FewestModules"
         case SmallestModules => "SmallestModules"
       }

diff --git a/linker-interface/shared/src/main/scala/org/scalajs/linker/interface/Report.scala b/linker-interface/shared/src/main/scala/org/scalajs/linker/interface/Report.scala
@@ -110,7 +110,7 @@ object Report {
     }
 
     private def writeModuleKind(kind: ModuleKind): Unit = {
-      val i = kind match {
+      val i = (kind: @unchecked) match {
         case ModuleKind.NoModule       => 0
         case ModuleKind.ESModule       => 1
         case ModuleKind.CommonJSModule => 2

diff --git a/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/ClassEmitter.scala b/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/ClassEmitter.scala
@@ -571,7 +571,7 @@ private[emitter] final class ClassEmitter(sjsGen: SJSGen) {
         methodFun0
       }
 
-      val field = namespace match {
+      val field = (namespace: @unchecked) match {
         case MemberNamespace.Private           => "p"
         case MemberNamespace.PublicStatic      => "s"
         case MemberNamespace.PrivateStatic     => "ps"
@@ -1220,7 +1220,7 @@ private[emitter] final class ClassEmitter(sjsGen: SJSGen) {
   private def genConstValueExportDef(exportName: String,
       exportedValue: js.Tree)(
       implicit pos: Position): WithGlobals[js.Tree] = {
-    moduleKind match {
+    (moduleKind: @unchecked) match {
       case ModuleKind.NoModule =>
         genAssignToNoModuleExportVar(exportName, exportedValue)
 
@@ -1261,7 +1261,7 @@ private[emitter] final class ClassEmitter(sjsGen: SJSGen) {
 
     val varScope = (className, field.name)
 
-    moduleKind match {
+    (moduleKind: @unchecked) match {
       case ModuleKind.NoModule =>
         /* Initial value of the export. Updates are taken care of explicitly
          * when we assign to the static field.

diff --git a/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/Emitter.scala b/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/Emitter.scala
@@ -78,7 +78,7 @@ final class Emitter(config: Emitter.Config) {
   def emit(moduleSet: ModuleSet, logger: Logger): Result = {
     val WithGlobals(body, globalRefs) = emitInternal(moduleSet, logger)
 
-    moduleKind match {
+    (moduleKind: @unchecked) match {
       case ModuleKind.NoModule =>
         assert(moduleSet.modules.size <= 1)
         val topLevelVars = moduleSet.modules
@@ -294,7 +294,7 @@ final class Emitter(config: Emitter.Config) {
         )
     ).toList.sortBy(_._1.name)
 
-    moduleKind match {
+    (moduleKind: @unchecked) match {
       case ModuleKind.NoModule =>
         WithGlobals(Nil)
 

diff --git a/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/FunctionEmitter.scala b/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/FunctionEmitter.scala
@@ -581,8 +581,7 @@ private[emitter] class FunctionEmitter(sjsGen: SJSGen) {
           }
 
         case Assign(select @ ArraySelect(array, index), rhs) =>
-          unnest(List(array, index, rhs)) {
-            case (List(newArray, newIndex, newRhs), env0) =>
+          unnest(array, index, rhs) { (newArray, newIndex, newRhs, env0) =>
               implicit val env = env0
               val genArray = transformExprNoChar(newArray)
               val genIndex = transformExprNoChar(newIndex)
@@ -615,8 +614,8 @@ private[emitter] class FunctionEmitter(sjsGen: SJSGen) {
           }
 
         case Assign(select @ JSSelect(qualifier, item), rhs) =>
-          unnest(List(qualifier, item, rhs)) {
-            case (List(newQualifier, newItem, newRhs), env0) =>
+          unnest(qualifier, item, rhs) {
+            (newQualifier, newItem, newRhs, env0) =>
               implicit val env = env0
               js.Assign(
                   genBracketSelect(transformExprNoChar(newQualifier),
@@ -625,8 +624,8 @@ private[emitter] class FunctionEmitter(sjsGen: SJSGen) {
           }
 
         case Assign(select @ JSSuperSelect(superClass, qualifier, item), rhs) =>
-          unnest(List(superClass, qualifier, item, rhs)) {
-            case (List(newSuperClass, newQualifier, newItem, newRhs), env0) =>
+          unnest(superClass, qualifier, item, rhs) {
+            (newSuperClass, newQualifier, newItem, newRhs, env0) =>
               implicit val env = env0
               genCallHelper("superSet", transformExprNoChar(newSuperClass),
                   transformExprNoChar(newQualifier), transformExprNoChar(item),
@@ -1069,17 +1068,39 @@ private[emitter] class FunctionEmitter(sjsGen: SJSGen) {
     /** Same as above, for a single argument */
     def unnest(arg: Tree)(makeStat: (Tree, Env) => js.Tree)(
         implicit env: Env): js.Tree = {
-      unnest(List(arg)) {
-        case (List(newArg), env) => makeStat(newArg, env)
+      unnest(List(arg)) { (newArgs, env) =>
+        val newArg :: Nil = newArgs
+        makeStat(newArg, env)
       }
     }
 
     /** Same as above, for two arguments */
-    def unnest(lhs: Tree, rhs: Tree)(
+    def unnest(arg1: Tree, arg2: Tree)(
         makeStat: (Tree, Tree, Env) => js.Tree)(
         implicit env: Env): js.Tree = {
-      unnest(List(lhs, rhs)) {
-        case (List(newLhs, newRhs), env) => makeStat(newLhs, newRhs, env)
+      unnest(List(arg1, arg2)) { (newArgs, env) =>
+        val newArg1 :: newArg2 :: Nil = newArgs
+        makeStat(newArg1, newArg2, env)
+      }
+    }
+
+    /** Same as above, for 3 arguments */
+    def unnest(arg1: Tree, arg2: Tree, arg3: Tree)(
+        makeStat: (Tree, Tree, Tree, Env) => js.Tree)(
+        implicit env: Env): js.Tree = {
+      unnest(List(arg1, arg2, arg3)) { (newArgs, env) =>
+        val newArg1 :: newArg2 :: newArg3 :: Nil = newArgs
+        makeStat(newArg1, newArg2, newArg3, env)
+      }
+    }
+
+    /** Same as above, for 4 arguments */
+    def unnest(arg1: Tree, arg2: Tree, arg3: Tree, arg4: Tree)(
+        makeStat: (Tree, Tree, Tree, Tree, Env) => js.Tree)(
+        implicit env: Env): js.Tree = {
+      unnest(List(arg1, arg2, arg3, arg4)) { (newArgs, env) =>
+        val newArg1 :: newArg2 :: newArg3 :: newArg4 :: Nil = newArgs
+        makeStat(newArg1, newArg2, newArg3, newArg4, env)
       }
     }
 
@@ -1702,8 +1723,8 @@ private[emitter] class FunctionEmitter(sjsGen: SJSGen) {
           }
 
         case JSSuperSelect(superClass, qualifier, item) =>
-          unnest(List(superClass, qualifier, item)) {
-            case (List(newSuperClass, newQualifier, newItem), env) =>
+          unnest(superClass, qualifier, item) {
+            (newSuperClass, newQualifier, newItem, env) =>
               redo(JSSuperSelect(newSuperClass, newQualifier, newItem))(env)
           }
 

diff --git a/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/SJSGen.scala b/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/SJSGen.scala
@@ -188,6 +188,10 @@ private[emitter] final class SJSGen(
       case BoxedFloatClass     => genIsFloat(expr)
       case BoxedDoubleClass    => typeof(expr) === "number"
       case BoxedStringClass    => typeof(expr) === "string"
+
+      case _ =>
+        throw new IllegalArgumentException(
+            s"hijacked class required but got ${className.nameString}")
     }
   }
 
@@ -351,7 +355,7 @@ private[emitter] final class SJSGen(
         }
 
       case irt.JSNativeLoadSpec.ImportWithGlobalFallback(importSpec, globalSpec) =>
-        moduleKind match {
+        (moduleKind: @unchecked) match {
           case ModuleKind.NoModule =>
             genLoadJSFromSpec(globalSpec, keepOnlyDangerousVarNames)
           case ModuleKind.ESModule | ModuleKind.CommonJSModule =>

diff --git a/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/VarGen.scala b/linker/shared/src/main/scala/org/scalajs/linker/backend/emitter/VarGen.scala
@@ -207,7 +207,7 @@ private[emitter] final class VarGen(jsGen: JSGen, nameGen: NameGen,
     if (moduleContext.public) {
       WithGlobals(tree)
     } else {
-      val export = config.moduleKind match {
+      val export = (config.moduleKind: @unchecked) match {
         case ModuleKind.NoModule =>
           throw new AssertionError("non-public module in NoModule mode")
 

diff --git a/linker/shared/src/main/scala/org/scalajs/linker/checker/IRChecker.scala b/linker/shared/src/main/scala/org/scalajs/linker/checker/IRChecker.scala
@@ -1486,7 +1486,7 @@ object IRChecker {
       extends AnyVal {
 
     override def toString(): String = {
-      val (pos, name) = nodeOrLinkedClass match {
+      val (pos, name) = (nodeOrLinkedClass: @unchecked) match {
         case tree: IRNode             => (tree.pos, tree.getClass.getSimpleName)
         case linkedClass: LinkedClass => (linkedClass.pos, "ClassDef")
       }

diff --git a/linker/shared/src/main/scala/org/scalajs/linker/frontend/LinkerFrontendImpl.scala b/linker/shared/src/main/scala/org/scalajs/linker/frontend/LinkerFrontendImpl.scala
@@ -45,7 +45,7 @@ final class LinkerFrontendImpl private (config: LinkerFrontendImpl.Config)
 
   private[this] val refiner: Refiner = new Refiner(config.commonConfig)
 
-  private[this] val splitter: ModuleSplitter = config.moduleSplitStyle match {
+  private[this] val splitter: ModuleSplitter = (config.moduleSplitStyle: @unchecked) match {
     case ModuleSplitStyle.FewestModules   => ModuleSplitter.maxSplitter()
     case ModuleSplitStyle.SmallestModules => ModuleSplitter.minSplitter()
   }

diff --git a/linker/shared/src/main/scala/org/scalajs/linker/frontend/modulesplitter/ModuleSplitter.scala b/linker/shared/src/main/scala/org/scalajs/linker/frontend/modulesplitter/ModuleSplitter.scala
@@ -155,7 +155,7 @@ final class ModuleSplitter private (analyzer: ModuleAnalyzer) {
       add(tle.tree.moduleID, tle.staticDependencies)
 
     for (mi <- unit.moduleInitializers) {
-      val dep = mi.initializer match {
+      val dep = (mi.initializer: @unchecked) match {
         case ModuleInitializerImpl.VoidMainMethod(className, _) =>
           className
         case ModuleInitializerImpl.MainMethodWithArgs(className, _, _) =>

diff --git a/test-suite/js/src/test/resources/SourceMapTestTemplate.scala b/test-suite/js/src/test/resources/SourceMapTestTemplate.scala
@@ -486,7 +486,7 @@ class Json extends Writer2{
         linePos = chLinePos
         charPos = chCharPos
         val kind: Int = chKind
-        kind match {
+        (kind: @unchecked) match {
           case Letter =>
             val first = chMark
             while (chKind == Letter || chKind == Digit) {
@@ -628,7 +628,7 @@ class Json extends Writer2{
     }
     def getJson(): JsValue = {
       val kind: Int = tokenKind
-      val result: JsValue = kind match {
+      val result: JsValue = (kind: @unchecked) match {
         case ID =>
           val result: JsValue = tokenValue match {
             case "true" => JsTrue

diff --git a/...src/test/scala/org/scalajs/testsuite/compiler/InstanceTestsHijackedBoxedClassesTest.scala b/...src/test/scala/org/scalajs/testsuite/compiler/InstanceTestsHijackedBoxedClassesTest.scala
@@ -72,7 +72,7 @@ class InstanceTestsHijackedBoxedClassesTest {
     assertTrue((1.2: Any).isInstanceOf[Float])
 
     // from the bug report
-    def test(x: Any): String = x match {
+    def test(x: Any): String = (x: @unchecked) match {
       case f: Float => "ok"
     }
     assertEquals("ok", test(0.2))

diff --git a/test-suite/js/src/test/scala/org/scalajs/testsuite/jsinterop/JSSymbolTest.scala b/test-suite/js/src/test/scala/org/scalajs/testsuite/jsinterop/JSSymbolTest.scala
@@ -169,7 +169,7 @@ class JSSymbolTest {
   @Test def native_with_overloaded_runtime_dispatch_methods(): Unit = {
     val obj = mkObject(
         sym1 -> { (x: Any) =>
-          x match {
+          (x: @unchecked) match {
             case x: Int    => x + 3
             case x: String => "Hello " + x
           }

diff --git a/test-suite/js/src/test/scala/org/scalajs/testsuite/library/ArrayOpsTest.scala b/test-suite/js/src/test/scala/org/scalajs/testsuite/library/ArrayOpsTest.scala
@@ -309,9 +309,11 @@ class ArrayOpsTest {
     import js.Any.jsArrayOps
 
     val array = js.Array[Any](1, "one", 2, "two", 3, "three")
-    val resultInferType = array.partitionMap {
-      case x: Int    => Left(x)
-      case x: String => Right(x)
+    val resultInferType = array.partitionMap { x =>
+      (x: @unchecked) match {
+        case x: Int    => Left(x)
+        case x: String => Right(x)
+      }
     }
     val result: (js.Array[Int], js.Array[String]) = resultInferType
     assertJSArrayPairEquals((js.Array(1, 2, 3), js.Array("one", "two", "three")), result)