Update check for secondary constructors

Author: biboudis

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

@@ -341,7 +341,7 @@ object Checking {
       if (!ok && !sym.is(Synthetic))
         fail(i"modifier `$flag` is not allowed for this definition")
 
-    if (sym.is(Inline) && sym.is(ParamAccessor) && sym.owner.isClass)
+    if (sym.is(Inline) && ((sym.is(ParamAccessor) && sym.owner.isClass) || sym.is(TermParam) && sym.owner.isClassConstructor))
       fail(ParamsNoInline(sym.owner))
 
     if (sym.is(ImplicitCommon)) {

tests/neg/i3900.scala

@@ -2,3 +2,6 @@ class Foo(inline val i: Int) // error
 case class Foo2(inline val i: Int) // error
 class Foo3(inline val i: Int) extends AnyVal // error
 trait Foo4(inline val i: Int) // error
+class Foo5() {
+  def this(inline x: Int) = this() // error
+}