call it declaration consistently

Author: Jendrik Wenke

compiler/src/dotty/tools/dotc/reporting/diagnostic/messages.scala

@@ -2080,18 +2080,18 @@ object messages {
     val explanation = ""
   }
 
-  case class DoubleDeclaration(decl: Symbol, previousSymbol: Symbol)(implicit ctx: Context) extends Message(DoubleDeclarationID) {
+  case class DoubleDeclaration(decl: Symbol, previousDecl: Symbol)(implicit ctx: Context) extends Message(DoubleDeclarationID) {
     val kind = "Duplicate Symbol"
     val msg = {
-      val details = if (decl.isRealMethod && previousSymbol.isRealMethod) {
+      val details = if (decl.isRealMethod && previousDecl.isRealMethod) {
         // compare the signatures when both symbols represent methods
-        decl.asTerm.signature.matchDegree(previousSymbol.asTerm.signature) match {
+        decl.asTerm.signature.matchDegree(previousDecl.asTerm.signature) match {
           case Signature.NoMatch => ""
           case Signature.ParamMatch => "\nOverloads with equal parameter types but different return types are not allowed."
           case Signature.FullMatch => "\nThe definitions have the same signature after erasure."
         }
       } else ""
-      hl"${decl.showLocated} is already defined as ${previousSymbol.showDcl} in line ${previousSymbol.pos.line + 1}." + details
+      hl"${decl.showLocated} is already defined as ${previousDecl.showDcl} in line ${previousDecl.pos.line + 1}." + details
     }
     val explanation = ""
   }

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

@@ -611,12 +611,12 @@ trait Checking {
       }
     }
 
-  /** Check that class does not define same symbol twice */
-  def checkNoDoubleDefs(cls: Symbol)(implicit ctx: Context): Unit = {
+  /** Check that class does not declare same symbol twice */
+  def checkNoDoubleDeclaration(cls: Symbol)(implicit ctx: Context): Unit = {
     val seen = new mutable.HashMap[Name, List[Symbol]] {
       override def default(key: Name) = Nil
     }
-    typr.println(i"check no double defs $cls")
+    typr.println(i"check no double declarations $cls")
 
     def checkDecl(decl: Symbol): Unit = {
       for (other <- seen(decl.name)) {
@@ -866,7 +866,7 @@ trait NoChecking extends ReChecking {
   override def checkImplicitParamsNotSingletons(vparamss: List[List[ValDef]])(implicit ctx: Context): Unit = ()
   override def checkFeasibleParent(tp: Type, pos: Position, where: => String = "")(implicit ctx: Context): Type = tp
   override def checkInlineConformant(tree: Tree, what: => String)(implicit ctx: Context) = ()
-  override def checkNoDoubleDefs(cls: Symbol)(implicit ctx: Context): Unit = ()
+  override def checkNoDoubleDeclaration(cls: Symbol)(implicit ctx: Context): Unit = ()
   override def checkParentCall(call: Tree, caller: ClassSymbol)(implicit ctx: Context) = ()
   override def checkSimpleKinded(tpt: Tree)(implicit ctx: Context): Tree = tpt
   override def checkNotSingleton(tpt: Tree, where: String)(implicit ctx: Context): Tree = tpt

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

@@ -1506,7 +1506,7 @@ class Typer extends Namer
       // Expand comments and type usecases
       cookComments(body1.map(_.symbol), self1.symbol)(ctx.localContext(cdef, cls).setNewScope)
 
-      checkNoDoubleDefs(cls)
+      checkNoDoubleDeclaration(cls)
       val impl1 = cpy.Template(impl)(constr1, parents1, self1, body1)
         .withType(dummy.termRef)
       checkVariance(impl1)