Fix core type in try ... with ... body (#1042)

Fixes #1040 by transforming the inferred type from source (instead of
inferring the type of the transformed expression).

Author: marzipankaiser

effekt/shared/src/main/scala/effekt/core/Transformer.scala

@@ -443,7 +443,7 @@ object Transformer extends Phase[Typechecked, CoreTransformed] {
 
       val transformedProg = transform(prog)
 
-      val answerType = transformedProg.tpe
+      val answerType = transform(Context.inferredTypeOf(prog))
 
       // create a fresh prompt, a variable referring to it, and a parameter binding it
       val promptId   = Id("p")

examples/pos/issue1040.check

@@ -0,0 +1 @@
+OK

examples/pos/issue1040.effekt

@@ -0,0 +1,14 @@
+effect hurl(n: String): Unit
+
+def result(): String / {} = {
+  try {
+    do hurl("OK")
+    <{"No return?" }> // <-- Replace '"No return?"' with '<>' and nothing gets printed
+  } with hurl {
+    def hurl(r) = r
+  }
+}
+
+def main() = {
+  println(result())
+}