scala · SethTisue · Aug 30, 2023 · Aug 25, 2023 · Aug 25, 2023 · Aug 25, 2023
diff --git a/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala b/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
@@ -531,19 +531,6 @@ trait ContextErrors extends splain.SplainErrors {
         setError(tree)
       }
 
-      //typedEta
-      private def mkUnderscoreNullaryEtaMessage(what: String) =
-        s"Methods without a parameter list and by-name params can $what be converted to functions as `m _`, " +
-          "write a function literal `() => m` instead"
-
-      final val UnderscoreNullaryEtaWarnMsg  = mkUnderscoreNullaryEtaMessage("no longer")
-      final val UnderscoreNullaryEtaErrorMsg = mkUnderscoreNullaryEtaMessage("not")
-
-      def UnderscoreNullaryEtaError(tree: Tree, actions: List[CodeAction]) = {
-        issueNormalTypeError(tree, UnderscoreNullaryEtaErrorMsg, actions)
-        setError(tree)
-      }
-
       def UnderscoreEtaError(tree: Tree) = {
         issueNormalTypeError(tree, "_ must follow method; cannot follow " + tree.tpe)
         setError(tree)

diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -4016,7 +4016,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
         return finish(ErroneousAnnotation)
       }
       if (currentRun.isScala3 && (/*annTypeSym.eq(SpecializedClass) ||*/ annTypeSym.eq(ElidableMethodClass)))
-        context.deprecationWarning(ann.pos, annTypeSym, s"@${annTypeSym.fullNameString} is ignored in Scala 3", "2.13.12")
+        context.warning(ann.pos, s"@${annTypeSym.fullNameString} is ignored in Scala 3", WarningCategory.Scala3Migration)
 
       /* Calling constfold right here is necessary because some trees (negated
        * floats and literals in particular) are not yet folded.
@@ -4972,19 +4972,22 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
 
           val result = typed(Function(Nil, methodValue) setSymbol funSym setPos pos, mode, pt)
 
+          val msg = "Methods without a parameter list and by-name params can no longer be converted to functions as `m _`, " +
+            "write a function literal `() => m` instead"
+
           val action = {
             val etaPos = pos.withEnd(pos.end + 2)
             if (currentUnit.sourceAt(etaPos).endsWith(" _"))
-              runReporting.codeAction("replace by function literal", etaPos, s"() => ${currentUnit.sourceAt(pos)}", UnderscoreNullaryEtaWarnMsg)
+              runReporting.codeAction("replace by function literal", etaPos, s"() => ${currentUnit.sourceAt(pos)}", msg)
             else Nil
           }
 
-          if (currentRun.isScala3) {
-            UnderscoreNullaryEtaError(methodValue, action)
-          } else {
-            context.deprecationWarning(pos, NoSymbol, UnderscoreNullaryEtaWarnMsg, "2.13.2", action)
-            result
-          }
+          if (currentRun.isScala3)
+            context.warning(pos, msg, WarningCategory.Scala3Migration, action)
+          else
+            context.deprecationWarning(pos, NoSymbol, msg, "2.13.2", action)
+
+          result
 
         case ErrorType =>
           methodValue

diff --git a/test/files/neg/deprecated-annots.check b/test/files/neg/deprecated-annots.check
@@ -1,6 +1,6 @@
-deprecated-annots.scala:9: warning: @scala.annotation.elidable is ignored in Scala 3
+deprecated-annots.scala:9: error: @scala.annotation.elidable is ignored in Scala 3
+Scala 3 migration messages are errors under -Xsource:3. Use -Wconf / @nowarn to filter them or add -Xmigration to demote them to warnings.
+Applicable -Wconf / @nowarn filters for this fatal warning: msg=<part of the message>, cat=scala3-migration, site=D
   @annotation.elidable(42)
    ^
-error: No warnings can be incurred under -Werror.
-1 warning
 1 error
diff --git a/test/files/neg/nullary-override-3a.check b/test/files/neg/nullary-override-3a.check
@@ -1,13 +1,25 @@
 nullary-override-3a.scala:4: error: method with a single empty parameter list overrides method without any parameter list
 def x: Int (defined in class A) [quickfixable]
+Scala 3 migration messages are errors under -Xsource:3. Use -Wconf / @nowarn to filter them or add -Xmigration to demote them to warnings.
+Applicable -Wconf / @nowarn filters for this fatal warning: msg=<part of the message>, cat=scala3-migration, site=B
 class B extends A { override def x(): Int = 4 }
                                  ^
 nullary-override-3a.scala:16: error: method with a single empty parameter list overrides method without any parameter list
 def x: String (defined in trait T1) [quickfixable]
+Scala 3 migration messages are errors under -Xsource:3. Use -Wconf / @nowarn to filter them or add -Xmigration to demote them to warnings.
+Applicable -Wconf / @nowarn filters for this fatal warning: msg=<part of the message>, cat=scala3-migration, site=Mix12b
 class Mix12b extends T1 with T2 { override def x() = "12b" }
                                                ^
+nullary-override-3a.scala:18: error: method without a parameter list overrides a method with a single empty one
+def x(): String (defined in trait T2) [quickfixable]
+Scala 3 migration messages are errors under -Xsource:3. Use -Wconf / @nowarn to filter them or add -Xmigration to demote them to warnings.
+Applicable -Wconf / @nowarn filters for this fatal warning: msg=<part of the message>, cat=scala3-migration, site=Mix21a
+class Mix21a extends T2 with T1 { override def x   = "21a" }
+                                               ^
 nullary-override-3a.scala:19: error: method with a single empty parameter list overrides method without any parameter list
 def x: String (defined in trait T1) [quickfixable]
+Scala 3 migration messages are errors under -Xsource:3. Use -Wconf / @nowarn to filter them or add -Xmigration to demote them to warnings.
+Applicable -Wconf / @nowarn filters for this fatal warning: msg=<part of the message>, cat=scala3-migration, site=Mix21b
 class Mix21b extends T2 with T1 { override def x() = "21b" }
                                                ^
-3 errors
+4 errors
diff --git a/test/files/neg/nullary-override-3b.check b/test/files/neg/nullary-override-3b.check
@@ -1,9 +1,13 @@
 nullary-override-3b.scala:6: error: method without a parameter list overrides a method with a single empty one
 def x(): Int (defined in class P) [quickfixable]
+Scala 3 migration messages are errors under -Xsource:3. Use -Wconf / @nowarn to filter them or add -Xmigration to demote them to warnings.
+Applicable -Wconf / @nowarn filters for this fatal warning: msg=<part of the message>, cat=scala3-migration, site=Q
 class Q extends P { override def x: Int = 4 }
                                  ^
 nullary-override-3b.scala:11: error: method without a parameter list overrides a method with a single empty one
 def x(): String (defined in trait T2) [quickfixable]
+Scala 3 migration messages are errors under -Xsource:3. Use -Wconf / @nowarn to filter them or add -Xmigration to demote them to warnings.
+Applicable -Wconf / @nowarn filters for this fatal warning: msg=<part of the message>, cat=scala3-migration, site=Mix12a
 class Mix12a extends T1 with T2 { override def x   = "12a" }
                                                ^
 2 errors
diff --git a/test/files/neg/nullary-override.check b/test/files/neg/nullary-override.check
@@ -10,9 +10,12 @@ class Mix12a extends T1 with T2 { override def x   = "12a" }
 nullary-override.scala:37: warning: method with a single empty parameter list overrides method without any parameter list [quickfixable]
 class Mix12b extends T1 with T2 { override def x() = "12b" }
                                                ^
+nullary-override.scala:39: warning: method without a parameter list overrides a method with a single empty one [quickfixable]
+class Mix21a extends T2 with T1 { override def x   = "21a" }
+                                               ^
 nullary-override.scala:40: warning: method with a single empty parameter list overrides method without any parameter list [quickfixable]
 class Mix21b extends T2 with T1 { override def x() = "21b" }
                                                ^
 error: No warnings can be incurred under -Werror.
-5 warnings
+6 warnings
 1 error
diff --git a/test/files/neg/t12851b.check b/test/files/neg/t12851b.check
@@ -0,0 +1,9 @@
+C_2.scala:2: warning: method (method f in trait T2) with a single empty parameter list overrides method without any parameter list
+class C extends T1 with T2
+      ^
+C_2.scala:2: warning: method (method g in trait T2) without a parameter list overrides a method with a single empty one
+class C extends T1 with T2
+      ^
+error: No warnings can be incurred under -Werror.
+2 warnings
+1 error
diff --git a/test/files/neg/t12851b/C_2.scala b/test/files/neg/t12851b/C_2.scala
@@ -0,0 +1,2 @@
+// scalac: -Werror
+class C extends T1 with T2
diff --git a/test/files/neg/t12851b/T_1.scala b/test/files/neg/t12851b/T_1.scala
@@ -0,0 +1,11 @@
+
+trait T1 {
+  def f: Int
+  def g(): Int
+  def v(): Int
+}
+trait T2 {
+  def f() = 42
+  def g = 42
+  val v = 42
+}
diff --git a/test/files/neg/t7187-3.check b/test/files/neg/t7187-3.check
@@ -13,12 +13,14 @@ t7187-3.scala:16: error: type mismatch;
  required: SamZero
   val t2Sam: SamZero = m2         // error, nilary methods don't eta-expand to SAM types
                        ^
-t7187-3.scala:27: error: Methods without a parameter list and by-name params can not be converted to functions as `m _`, write a function literal `() => m` instead [quickfixable]
-  val t7 = m1 _ // error: eta-expanding a nullary method
-           ^
 t7187-3.scala:14: warning: An unapplied 0-arity method was eta-expanded (due to the expected type () => Any), rather than applied to `()`.
 Write m2() to invoke method m2, or change the expected type.
   val t2: () => Any  = m2   // eta-expanded with lint warning
                        ^
+t7187-3.scala:27: error: Methods without a parameter list and by-name params can no longer be converted to functions as `m _`, write a function literal `() => m` instead [quickfixable]
+Scala 3 migration messages are errors under -Xsource:3. Use -Wconf / @nowarn to filter them or add -Xmigration to demote them to warnings.
+Applicable -Wconf / @nowarn filters for this fatal warning: msg=<part of the message>, cat=scala3-migration, site=EtaExpand214.t7
+  val t7 = m1 _ // error: eta-expanding a nullary method
+           ^
 1 warning
 4 errors
diff --git a/test/files/neg/t7187-deprecation.check b/test/files/neg/t7187-deprecation.check
@@ -13,14 +13,16 @@ t7187-deprecation.scala:20: error: type mismatch;
  required: SamZero
   val t2Sam: SamZero = m2         // error, nilary methods don't eta-expand to SAM types
                        ^
-t7187-deprecation.scala:31: error: Methods without a parameter list and by-name params can not be converted to functions as `m _`, write a function literal `() => m` instead [quickfixable]
-  val t7 = m1 _ // error: eta-expanding a nullary method
-           ^
 t7187-deprecation.scala:24: warning: Auto-application to `()` is deprecated. Supply the empty argument list `()` explicitly to invoke method m2,
 or remove the empty argument list from its definition (Java-defined methods are exempt).
 In Scala 3, an unapplied method like this will be eta-expanded into a function. [quickfixable]
   val t5 = m2 // warn: apply, ()-insertion
            ^
+t7187-deprecation.scala:31: error: Methods without a parameter list and by-name params can no longer be converted to functions as `m _`, write a function literal `() => m` instead [quickfixable]
+Scala 3 migration messages are errors under -Xsource:3. Use -Wconf / @nowarn to filter them or add -Xmigration to demote them to warnings.
+Applicable -Wconf / @nowarn filters for this fatal warning: msg=<part of the message>, cat=scala3-migration, site=EtaExpand214.t7
+  val t7 = m1 _ // error: eta-expanding a nullary method
+           ^
 t7187-deprecation.scala:40: warning: Auto-application to `()` is deprecated. Supply the empty argument list `()` explicitly to invoke method boom,
 or remove the empty argument list from its definition (Java-defined methods are exempt).
 In Scala 3, an unapplied method like this will be eta-expanded into a function. [quickfixable]

diff --git a/test/files/pos/t12851c/ScalaNumber.java b/test/files/pos/t12851c/ScalaNumber.java
@@ -0,0 +1,20 @@
+/*
+ * Scala (https://www.scala-lang.org)
+ *
+ * Copyright EPFL and Lightbend, Inc.
+ *
+ * Licensed under Apache License 2.0
+ * (http://www.apache.org/licenses/LICENSE-2.0).
+ *
+ * See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
+ */
+
+package scala.math;
+
+/** A marker class for Number types introduced by Scala
+ */
+public abstract class ScalaNumber extends java.lang.Number {
+  protected abstract boolean isWhole();
+  public abstract Object underlying();
+}
diff --git a/test/files/pos/t12851c/ScalaNumericConversions.scala b/test/files/pos/t12851c/ScalaNumericConversions.scala
@@ -0,0 +1,30 @@
+//> using option -Werror
+/*
+ * Scala (https://www.scala-lang.org)
+ *
+ * Copyright EPFL and Lightbend, Inc.
+ *
+ * Licensed under Apache License 2.0
+ * (http://www.apache.org/licenses/LICENSE-2.0).
+ *
+ * See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
+ */
+
+package scala
+package math
+
+/** A slightly more specific conversion trait for classes which
+ *  extend ScalaNumber (which excludes value classes.)
+ */
+trait ScalaNumericConversions extends ScalaNumber with ScalaNumericAnyConversions {
+  def underlying: Object
+}
+
+/** Conversions which present a consistent conversion interface
+ *  across all the numeric types, suitable for use in value classes.
+ */
+trait ScalaNumericAnyConversions extends Any {
+  /** @return `'''true'''` if this number has no decimal component, `'''false'''` otherwise. */
+  def isWhole: Boolean
+}