Restore error checking

Author: Jentsch

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

@@ -1445,6 +1445,10 @@ trait Applications extends Compatibility {
             })
             unapplyPatterns += typed(term, argTypes.head)
             argTypes = argTypes.tail
+        } else {
+          // Check for positional arguments
+          if (argTypes != Nil || bunchedArgs != Nil)
+            report.error(UnapplyInvalidNumberOfArguments(qual, argTypes), tree.srcPos)
         }
 
         val result = assignType(cpy.UnApply(tree)(unapplyFn, unapplyImplicits(unapplyApp), unapplyPatterns.result), ownType)

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

@@ -34,6 +34,7 @@ class NamedPatternMatching {
     implicit val testGroup: TestGroup = TestGroup("compileNeg")
     aggregateTests(
       compileFile("tests/neg/negNamedPatternMatching.scala", defaultOptions),
+      compileFile("tests/neg/bad-unapplies.scala", defaultOptions),
     ).checkExpectedErrors()
   }