Check trivial trait args

som-snytt · som-snytt · commit 720c1cd4b33a · 2025-03-30T23:32:14.000-07:00
diff --git a/src/compiler/scala/tools/nsc/ast/TreeBrowsers.scala b/src/compiler/scala/tools/nsc/ast/TreeBrowsers.scala
@@ -189,7 +189,7 @@ abstract class TreeBrowsers {
         }
       }
 
-      jTree.addTreeSelectionListener(new javax.swing.event.TreeSelectionListener() {
+      jTree.addTreeSelectionListener(new javax.swing.event.TreeSelectionListener {
         def valueChanged(e: javax.swing.event.TreeSelectionEvent): Unit = {
           textArea.setText(e.getPath().getLastPathComponent().toString)
           infoPanel.update(e.getPath().getLastPathComponent())
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -1587,7 +1587,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
       val decodedtpt = app.callee
       val argssAreTrivial = argss == Nil || argss == ListOfNil
 
-      // we cannot avoid cyclic references with `initialize` here, because when type macros arrive,
+      // we cannot avoid cyclic references with `initialize` here, because when type macros arrive [sic],
       // we'll have to check the probe for isTypeMacro anyways.
       // therefore I think it's reasonable to trade a more specific "inherits itself" error
       // for a generic, yet understandable "cyclic reference" error
@@ -1599,7 +1599,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
 
       def cookIfNeeded(tpt: Tree) = if (context.unit.isJava) tpt modifyType rawToExistential else tpt
       cookIfNeeded(if (probe.isTrait || inMixinPosition) {
-        if (!argssAreTrivial) {
+        if (!argss.isEmpty) {
           if (probe.isTrait) ConstrArgsInParentWhichIsTraitError(encodedtpt, probe)
           else () // a class in a mixin position - this warrants an error in `validateParentClasses`
                   // therefore here we do nothing, e.g. don't check that the # of ctor arguments
diff --git a/test/files/neg/t6805.check b/test/files/neg/t6805.check
@@ -0,0 +1,16 @@
+t6805.scala:4: error: trait T is a trait; does not take constructor arguments
+class C extends T() // error
+                ^
+t6805.scala:7: error: trait T is a trait; does not take constructor arguments
+class Y extends X with T() // error
+                       ^
+t6805.scala:10: error: trait T is a trait; does not take constructor arguments
+  def t: T = new T() {} // error
+                 ^
+t6805.scala:11: error: trait T is abstract; cannot be instantiated
+  def u: T = new T()  // error
+             ^
+t6805.scala:12: error: trait T is a trait; does not take constructor arguments
+  def v: T = new X with T()  // error
+                        ^
+5 errors
diff --git a/test/files/neg/t6805.scala b/test/files/neg/t6805.scala
@@ -0,0 +1,13 @@
+
+trait T
+
+class C extends T() // error
+
+class X
+class Y extends X with T() // error
+
+object funcs {
+  def t: T = new T() {} // error
+  def u: T = new T()  // error
+  def v: T = new X with T()  // error
+}

Original file line number	Diff line number	Diff line change
`@@ -189,7 +189,7 @@ abstract class TreeBrowsers {`
`189`	`189`	`}`
`190`	`190`	`}`
`191`	`191`
`192`		`- jTree.addTreeSelectionListener(new javax.swing.event.TreeSelectionListener() {`
	`192`	`+ jTree.addTreeSelectionListener(new javax.swing.event.TreeSelectionListener {`
`193`	`193`	`def valueChanged(e: javax.swing.event.TreeSelectionEvent): Unit = {`
`194`	`194`	`textArea.setText(e.getPath().getLastPathComponent().toString)`
`195`	`195`	`infoPanel.update(e.getPath().getLastPathComponent())`