Compiler incorrectly tries to invoke context function passed as argument #10825
Description
Minimized code
trait A { def apply():Int } trait B { def apply():Int } class MWE2 { type Op = (A, B) ?=> Int def doOp(op:Op):Int = { implicit val a:A = new A{ def apply():Int = 2} implicit val b:B = new B{ def apply():Int = 3} op } def main(args:Array[String]):Unit = { val op:Op = { summon[A]() + summon[B]() } implicit val a:A = new A{ def apply():Int = 6} implicit val b:B = new B{ def apply():Int = 7} Console.println(doOp(op)) } }Output
[error] 17 | summon[A]() + summon[B]() [error] | ^ [error] |ambiguous implicit arguments: both value evidence$1 and value a match type A of parameter x of method summon in object Predef [error] -- Error: src/main/scala/MWE2.scala:21:27 [error] 21 | Console.println(doOp(op)) [error] | ^ [error] |ambiguous implicit arguments: both value evidence$5 and value a match type A of parameter of MWE2.this.Op [error] |which is an alias of: (A, B) ?=> Int [error] two errors found [error] (Compile / compileIncremental) Compilation failed [error] Total time: 8 s, completed Dec 16, 2020 5:48:13 PMExpectation
op should not be invoked in main but should instead be passed to doOp.
Additionally, if the compiler is supposed to invoke it in main (which would be very surprising), the result should be a type error (found Int, required Op).
Further a should not be ambiguous with some anonymous evidence when I'm not even using any context bounds or anything else implicits / givens related that would be generating evidence.