Update tests and more info for errors

Author: liufengyun

compiler/src/dotty/tools/dotc/transform/init/ParamOverridingCheck.scala

@@ -134,6 +134,9 @@ object ParamOverridingCheck:
             val args = evalArgs(argss.flatten, thisV, cls)
             thisV.callConstructor(ref.symbol, args)
 
+          case _ =>
+            report.error("Unexpected rhs = " + ddef.rhs.show, ddef.rhs)
+
     }
   end extension
 

tests/init/neg/override16.scala

@@ -8,11 +8,11 @@ class B(val a: A) {
   val b = a.f
 }
 
-class C(override val a: A) extends B(new A(10))  // ok
+class C(override val a: A) extends B(new A(10))  // error: overriding with different value
 
 class M(val a: A)
 
-class N(override val a: A) extends M(new A(10))
+class N(override val a: A) extends M(new A(10))  // error: overriding with different value
 
 class X(val a: A) {
   a.f