illTyped vs c.eval

c.eval()

scala> def snc_impl(c: blackbox.Context)(s: c.Expr[String]): c.Tree = {
     |   import c.universe._
     |   val Literal(Constant(code:String)) = s.tree; val wrapped = q""" { lazy val ignore = { ${c.parse(code)} }; () } """
     |   val err = try { c.eval(c.Expr[Unit](wrapped)); None } catch { case e: Throwable => Some(e) }
     |   err match {
     |     case Some(e) => c.info(NoPosition, e.getMessage, true); q"()"
     |     case None => c.abort(NoPosition, "unexpected success")
     |   }
     | }
snc_impl: (c: scala.reflect.macros.blackbox.Context)(s: c.Expr[String])c.Tree

scala> def snc(s: String): Unit = macro snc_impl
defined term macro snc: (s: String)Unit

scala> snc ( """ class Bah { type R; def foo(r: AnyRef) = ???; def foo(r: R) = ??? } """ )
reflective compilation has failed:

double definition:
def foo(r: Object): Nothing at line 1 and
def foo(r: Bah.this.R): Nothing at line 1
have same type after erasure: (r: Object)Nothing

scala> snc ( """ class Bah { type R; def foo(r: AnyRef) = ??? } """ )
<console>:15: error: unexpected success
       snc ( """ class Bah { type R; def foo(r: AnyRef) = ??? } """ )
           ^
           
scala> snc ( """ { class Boo  { type R; def foo(r: AnyRef) = ???; def foo(r: R) = ??? } ; throw new Error("") } """ )
reflective compilation has failed:

double definition:
def foo(r: Object): Nothing at line 1 and
def foo(r: Boo.this.R): Nothing at line 1
have same type after erasure: (r: Object)Nothing

illTyped

scala> class Bah { type R; def foo(r: AnyRef) = ???; def foo(r: R) = ??? }
<console>:42: error: double definition:
def foo(r: AnyRef): Nothing at line 42 and
def foo(r: Bah.this.R): Nothing at line 42
have same type after erasure: (r: Object)Nothing
       class Bah { type R; def foo(r: AnyRef) = ???; def foo(r: R) = ??? }
                                                         ^

scala> import shapeless.test.illTyped
import shapeless.test.illTyped

scala> illTyped("""class Bah { type R; def foo(r: AnyRef) = ???; def foo(r: R) = ??? }""")
<console>:44: error: Type-checking succeeded unexpectedly.
Expected some error.
       illTyped("""class Bah { type R; def foo(r: AnyRef) = ???; def foo(r: R) = ??? }""")
               ^