Change 'is abstract; cannot be instantiated' to Message

3 files changed, 13 insertions, 2 deletions

diff --git a/compiler/src/dotty/tools/dotc/reporting/diagnostic/ErrorMessageID.java b/compiler/src/dotty/tools/dotc/reporting/diagnostic/ErrorMessageID.java
index c74130b44..2bf15cb7c 100644
--- a/compiler/src/dotty/tools/dotc/reporting/diagnostic/ErrorMessageID.java
+++ b/compiler/src/dotty/tools/dotc/reporting/diagnostic/ErrorMessageID.java
@@ -49,7 +49,9 @@ public enum ErrorMessageID {
     OverridesNothingButNameExistsID,
     ForwardReferenceExtendsOverDefinitionID,
     ExpectedTokenButFoundID,
-    MixedLeftAndRightAssociativeOpsID;
+    MixedLeftAndRightAssociativeOpsID,
+    CantInstantiateAbstractClassOrTraitID,
+    ;
 
     public int errorNumber() {
         return ordinal() - 2;
diff --git a/compiler/src/dotty/tools/dotc/reporting/diagnostic/messages.scala b/compiler/src/dotty/tools/dotc/reporting/diagnostic/messages.scala
index 7fccebef9..1ad606076 100644
--- a/compiler/src/dotty/tools/dotc/reporting/diagnostic/messages.scala
+++ b/compiler/src/dotty/tools/dotc/reporting/diagnostic/messages.scala
@@ -1127,4 +1127,12 @@ object messages {
           |""".stripMargin
   }
 
+  case class CantInstantiateAbstractClassOrTrait(cls: Symbol, isTrait: Boolean)(implicit ctx: Context)
+  extends Message(CantInstantiateAbstractClassOrTraitID) {
+    val kind = "Usage"
+    private val traitOrAbstract = if (isTrait) hl"a trait" else hl"abstract"
+    val msg = hl"""${cls.name} is ${traitOrAbstract}; it cannot be instantiated"""
+    val explanation = ""
+  }
+
 }
diff --git a/compiler/src/dotty/tools/dotc/typer/Checking.scala b/compiler/src/dotty/tools/dotc/typer/Checking.scala
index fb0497c2b..48f9243f7 100644
--- a/compiler/src/dotty/tools/dotc/typer/Checking.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Checking.scala
@@ -29,6 +29,7 @@ import ErrorReporting.{err, errorType}
 import config.Printers.typr
 import collection.mutable
 import SymDenotations.NoCompleter
+import dotty.tools.dotc.reporting.diagnostic.messages.CantInstantiateAbstractClassOrTrait
 import dotty.tools.dotc.transform.ValueClasses._
 
 object Checking {
@@ -103,7 +104,7 @@ object Checking {
       case tref: TypeRef =>
         val cls = tref.symbol
         if (cls.is(AbstractOrTrait))
-          ctx.error(em"$cls is abstract; cannot be instantiated", pos)
+          ctx.error(CantInstantiateAbstractClassOrTrait(cls, isTrait = cls.is(Trait)), pos)
         if (!cls.is(Module)) {
           // Create a synthetic singleton type instance, and check whether
           // it conforms to the self type of the class as seen from that instance.