Fix #7296: Don't flag setter names as operator names

Author: odersky

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

@@ -278,11 +278,12 @@ object Checking {
   def checkValidOperator(sym: Symbol)(implicit ctx: Context): Unit =
     sym.name.toTermName match {
       case name: SimpleName
-      if name.exists(isOperatorPart) &&
-        !sym.getAnnotation(defn.AlphaAnnot).isDefined &&
-        !sym.is(Synthetic) &&
-        !name.isConstructorName &&
-        ctx.settings.strict.value =>
+      if name.exists(isOperatorPart)
+         && !name.isSetterName
+         && !name.isConstructorName
+         && !sym.getAnnotation(defn.AlphaAnnot).isDefined
+         && !sym.is(Synthetic)
+         && ctx.settings.strict.value =>
         ctx.deprecationWarning(
           i"$sym has an operator name; it should come with an @alpha annotation", sym.sourcePos)
       case _ =>

compiler/test/dotty/tools/dotc/CompilationTests.scala

@@ -57,7 +57,8 @@ class CompilationTests extends ParallelTesting {
         defaultOptions.and("-nowarn", "-Xfatal-warnings")
       ),
       compileFile("tests/pos-special/typeclass-scaling.scala", defaultOptions.and("-Xmax-inlines", "40")),
-      compileFile("tests/pos-special/indent-colons.scala", defaultOptions.and("-Yindent-colons"))
+      compileFile("tests/pos-special/indent-colons.scala", defaultOptions.and("-Yindent-colons")),
+      compileFile("tests/pos-special/i7296.scala", defaultOptions.and("-strict", "-deprecation", "-Xfatal-warnings"))
     ).checkCompile()
   }
 

tests/pos-special/i7296.scala

@@ -0,0 +1,2 @@
+class Foo
+  private var blah: Double = 0L