Merge pull request #275 from scala/backport-lts-3.3-22604

Backport "Check exhaustivity of any case class" to 3.3 LTS

Author: tgodzik

compiler/src/dotty/tools/backend/jvm/BCodeSkelBuilder.scala

@@ -169,7 +169,7 @@ trait BCodeSkelBuilder extends BCodeHelpers {
 
     /* ---------------- helper utils for generating classes and fields ---------------- */
 
-    def genPlainClass(cd0: TypeDef) = cd0 match {
+    def genPlainClass(cd0: TypeDef) = (cd0: @unchecked) match {
       case TypeDef(_, impl: Template) =>
       assert(cnode == null, "GenBCode detected nested methods.")
 

compiler/src/dotty/tools/dotc/core/Comments.scala

@@ -405,15 +405,10 @@ object Comments {
       val Trim = "(?s)^[\\s&&[^\n\r]]*(.*?)\\s*$".r
 
       val raw = ctx.docCtx.flatMap(_.docstring(sym).map(_.raw)).getOrElse("")
-      defs(sym) ++= defines(raw).map {
-        str => {
-          val start = skipWhitespace(str, "@define".length)
-          val (key, value) = str.splitAt(skipVariable(str, start))
-          key.drop(start) -> value
-        }
-      } map {
-        case (key, Trim(value)) =>
-          variableName(key) -> value.replaceAll("\\s+\\*+$", "")
+      defs(sym) ++= defines(raw).map { str =>
+        val start = skipWhitespace(str, "@define".length)
+        val (key, Trim(value)) = str.splitAt(skipVariable(str, start)): @unchecked
+        variableName(key.drop(start)) -> value.replaceAll("\\s+\\*+$", "")
       }
     }
 

compiler/src/dotty/tools/dotc/transform/patmat/Space.scala

@@ -813,7 +813,6 @@ object SpaceEngine {
   }
 
   private def exhaustivityCheckable(sel: Tree)(using Context): Boolean = {
-    val seen = collection.mutable.Set.empty[Symbol]
 
     // Possible to check everything, but be compatible with scalac by default
     def isCheckable(tp: Type): Boolean =
@@ -828,10 +827,7 @@ object SpaceEngine {
       }) ||
       tpw.isRef(defn.BooleanClass) ||
       classSym.isAllOf(JavaEnumTrait) ||
-      classSym.is(Case) && {
-        if seen.add(classSym) then productSelectorTypes(tpw, sel.srcPos).exists(isCheckable(_))
-        else true // recursive case class: return true and other members can still fail the check
-      }
+      classSym.is(Case)
 
     !sel.tpe.hasAnnotation(defn.UncheckedAnnot)
     && {

compiler/src/dotty/tools/dotc/typer/Implicits.scala

@@ -1290,29 +1290,30 @@ trait Implicits:
             if alt1.isExtension then
               // Fall back: if both results are extension method applications,
               // compare the extension methods instead of their wrappers.
-              def stripExtension(alt: SearchSuccess) = methPart(stripApply(alt.tree)).tpe
-              (stripExtension(alt1), stripExtension(alt2)) match
-                case (ref1: TermRef, ref2: TermRef) =>
-                  // ref1 and ref2 might refer to type variables owned by
-                  // alt1.tstate and alt2.tstate respectively, to compare the
-                  // alternatives correctly we need a TyperState that includes
-                  // constraints from both sides, see
-                  // tests/*/extension-specificity2.scala for test cases.
-                  val constraintsIn1 = alt1.tstate.constraint ne ctx.typerState.constraint
-                  val constraintsIn2 = alt2.tstate.constraint ne ctx.typerState.constraint
-                  def exploreState(alt: SearchSuccess): TyperState =
-                    alt.tstate.fresh(committable = false)
-                  val comparisonState =
-                    if constraintsIn1 && constraintsIn2 then
-                      exploreState(alt1).mergeConstraintWith(alt2.tstate)
-                    else if constraintsIn1 then
-                      exploreState(alt1)
-                    else if constraintsIn2 then
-                      exploreState(alt2)
-                    else
-                      ctx.typerState
-
-                  diff = inContext(ctx.withTyperState(comparisonState)):
+              def stripExtension(alt: SearchSuccess) =
+                methPart(stripApply(alt.tree)).tpe: @unchecked match { case ref: TermRef => ref }
+              val ref1 = stripExtension(alt1)
+              val ref2 = stripExtension(alt2)
+              // ref1 and ref2 might refer to type variables owned by
+              // alt1.tstate and alt2.tstate respectively, to compare the
+              // alternatives correctly we need a TyperState that includes
+              // constraints from both sides, see
+              // tests/*/extension-specificity2.scala for test cases.
+              val constraintsIn1 = alt1.tstate.constraint ne ctx.typerState.constraint
+              val constraintsIn2 = alt2.tstate.constraint ne ctx.typerState.constraint
+              def exploreState(alt: SearchSuccess): TyperState =
+                alt.tstate.fresh(committable = false)
+              val comparisonState =
+                if constraintsIn1 && constraintsIn2 then
+                  exploreState(alt1).mergeConstraintWith(alt2.tstate)
+                else if constraintsIn1 then
+                  exploreState(alt1)
+                else if constraintsIn2 then
+                  exploreState(alt2)
+                else
+                  ctx.typerState
+
+              diff = inContext(ctx.withTyperState(comparisonState)):
                     compare(ref1, ref2)
             else // alt1 is a conversion, prefer extension alt2 over it
               diff = -1

compiler/test/dotty/tools/scripting/BashExitCodeTests.scala

@@ -62,6 +62,9 @@ class BashExitCodeTests:
   @Test def xPluginList   = scala("-Xplugin-list")(0)
   @Test def vPhases       = scala("-Vphases")(0)
 
+  @Test def replEval      =
+    scala("--repl-quit-after-init", "--repl-init-script", "'val i = 2 * 2; val j = i + 2'")(0)
+
   /** A utility for running two commands in a row, like you do in bash. */
   extension (inline u1: Unit) inline def & (inline u2: Unit): Unit = { u1; u2 }
 end BashExitCodeTests

library/src/scala/annotation/newMain.scala

@@ -253,6 +253,7 @@ final class newMain extends MainAnnotation[FromString, Any]:
             case (arg +: t, "") => recurse(t, arg, acc)
             case (arg +: t, l) if l.length + 1 + arg.length <= maxLength => recurse(t, s"$l $arg", acc)
             case (arg +: t, l) => recurse(t, arg, acc :+ l)
+            case (_, _) => acc
           }
 
         recurse(argsUsage, "", Vector()).toList

scaladoc/src/dotty/tools/scaladoc/site/templates.scala

@@ -102,11 +102,9 @@ case class TemplateFile(
       ctx.layouts.getOrElse(name, throw new RuntimeException(s"No layouts named $name in ${ctx.layouts}"))
     )
 
-    def asJavaElement(o: Object): Object = o match
-      case m: Map[_, _] => m.transform {
-        case (k: String, v: Object) => asJavaElement(v)
-      }.asJava
-      case l: List[_] => l.map(x => asJavaElement(x.asInstanceOf[Object])).asJava
+    def asJavaElement(o: Any): Any = o match
+      case m: Map[?, ?] => m.transform { (k, v) => asJavaElement(v) }.asJava
+      case l: List[?] => l.map(asJavaElement).asJava
       case other => other
 
     // Library requires mutable maps..

tests/pos/switches.scala

@@ -42,6 +42,7 @@ class Test {
     case IntAnyVal(100) => 2
     case IntAnyVal(1000) => 3
     case IntAnyVal(10000) => 4
+    case _ => -1
   }
 }
 

tests/warn/i15662.scala

@@ -5,6 +5,7 @@ case class Composite[T](v: T)
 def m(composite: Composite[?]): Unit =
   composite match {
     case Composite[Int](v) => println(v)  // warn: cannot be checked at runtime
+    case _ => println("OTHER")
   }
 
 def m2(composite: Composite[?]): Unit =

tests/warn/i21218.scala

@@ -6,5 +6,6 @@ def Test[U, A](thisElem: A, thatElem: U) = {
       case (`passedEnd`, r: U @unchecked) => (thisElem, r)
       case (l: A @unchecked, `passedEnd`) => (l, thatElem)
       case t: (A, U) @unchecked           => t // false-positive warning
+      case (t1, t2) => (t1, t2)
     }
 }

tests/warn/i21525.scala

@@ -1,7 +1,6 @@
 //> using options -Werror -Wunused:imports
 
 import scala.reflect.{Typeable, TypeTest}
-import compiletime.*
 
 trait A {
   type B
@@ -22,7 +21,7 @@ def f(a: A, b: a.B): Boolean = {
 
 trait T:
   type X
-  given Typeable[X] = deferred
+  given tpe: Typeable[X]
 
 def g(t: T, x: Any) =
   import t.X

tests/warn/i22590.arity2.scala

@@ -0,0 +1,15 @@
+sealed trait T_B
+case class CC_A() extends T_B
+case class CC_C() extends T_B
+
+sealed trait T_A
+case class CC_B[B](a: B,b:T_B) extends T_A
+
+
+@main def test() = {
+  val v_a: CC_B[Int] = null
+  val v_b: Int = v_a match { // warn: match may not be exhaustive.
+    case CC_B(12, CC_A()) => 0
+    case CC_B(_, CC_C()) => 0
+  }
+}

tests/warn/i22590.scala

@@ -0,0 +1,9 @@
+sealed trait T_A
+case class CC_B[T](a: T) extends T_A
+
+@main def test() = {
+  val v_a: CC_B[Int] = CC_B(10)
+  val v_b: Int = v_a match{ // warn: match may not be exhaustive.
+    case CC_B(12) => 0
+  }
+}

tests/warn/opaque-match.scala

@@ -13,8 +13,10 @@ def Test[T] =
     case _: C => ???   // ok
   C() match
     case _: O.T => ???  // warn
+    case _ => ???
   C() match
     case _: T => ???   // warn
+    case _ => ???
 
   (??? : Any) match
     case _: List[O.T] => ???  // warn

tests/pos/t10373.scala renamed to tests/warn/t10373.scala

@@ -1,4 +1,4 @@
-//> using options -Xfatal-warnings -deprecation -feature
+//> using options -deprecation -feature
 
 abstract class Foo {
   def bar(): Unit = this match {
@@ -7,7 +7,7 @@ abstract class Foo {
                     // Works fine
   }
 
-  def baz(that: Foo): Unit = (this, that) match {
+  def baz(that: Foo): Unit = (this, that) match { // warn: match may not be exhaustive.
     case (Foo_1(), _) => //do something
     case (Foo_2(), _) => //do something
                          // match may not be exhaustive