Fix #7387: Avoid comparing NoType with other types

nicolasstucki · nicolasstucki · commit 877ad05782b7 · 2019-10-08T18:51:36.000+02:00
diff --git a/compiler/src/dotty/tools/dotc/core/TypeComparer.scala b/compiler/src/dotty/tools/dotc/core/TypeComparer.scala
@@ -1058,7 +1058,7 @@ class TypeComparer(initctx: Context) extends ConstraintHandling[AbsentContext] w
     }
 
     // begin recur
-    if (tp2 eq NoType) false
+    if (tp1.eq(NoType) || tp2.eq(NoType)) false
     else if (tp1 eq tp2) true
     else {
       val saved = constraint
diff --git a/tests/neg/i7387.scala b/tests/neg/i7387.scala
@@ -0,0 +1,2 @@
+type E = A.B { type C = D } // error: Not found: A
+def g = summon[E] // error: no implicit argument of type E

Original file line number	Diff line number	Diff line change
`@@ -1058,7 +1058,7 @@ class TypeComparer(initctx: Context) extends ConstraintHandling[AbsentContext] w`
`1058`	`1058`	`}`
`1059`	`1059`
`1060`	`1060`	`// begin recur`
`1061`		`- if (tp2 eq NoType) false`
	`1061`	`+ if (tp1.eq(NoType) \|\| tp2.eq(NoType)) false`
`1062`	`1062`	`else if (tp1 eq tp2) true`
`1063`	`1063`	`else {`
`1064`	`1064`	`val saved = constraint`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+type E = A.B { type C = D } // error: Not found: A`
	`2`	`+def g = summon[E] // error: no implicit argument of type E`