Fix isPureClass test

Author: odersky

compiler/src/dotty/tools/dotc/cc/CaptureOps.scala

@@ -231,7 +231,11 @@ extension (cls: ClassSymbol)
           && bc.givenSelfType.dealiasKeepAnnots.match
             case CapturingType(_, refs) => refs.isAlwaysEmpty
             case RetainingType(_, refs) => refs.isEmpty
-            case selfType => selfType.exists && selfType.captureSet.isAlwaysEmpty
+            case selfType =>
+              isCaptureChecking  // At Setup we have not processed self types yet, so
+                                 // unless a self type is explicitly given, we can't tell
+                                 // and err on the side of impure.
+              && selfType.exists && selfType.captureSet.isAlwaysEmpty
 
 extension (sym: Symbol)
 

tests/neg-custom-args/captures/exception-definitions.check

@@ -6,8 +6,8 @@
 -- Error: tests/neg-custom-args/captures/exception-definitions.scala:7:12 ----------------------------------------------
 7 |    val x = c  // error
   |            ^
-  |(c : Any^) cannot be referenced here; it is not included in the allowed capture set {} of pure base class class Throwable
--- Error: tests/neg-custom-args/captures/exception-definitions.scala:8:8 -----------------------------------------------
+  |(c : Any^) cannot be referenced here; it is not included in the allowed capture set {} of the self type of class Err2
+-- Error: tests/neg-custom-args/captures/exception-definitions.scala:8:13 ----------------------------------------------
 8 |  class Err3(c: Any^) extends Exception // error
-  |  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  |  reference (Err3.this.c : Any^) is not included in the allowed capture set {} of pure base class class Throwable
+  |             ^
+  |       reference (Err3.this.c : Any^) is not included in the allowed capture set {} of the self type of class Err3

tests/neg-custom-args/captures/leaked-curried.check

@@ -2,10 +2,7 @@
 14 |        () => () => io // error
    |                    ^^
    |(io : Cap^) cannot be referenced here; it is not included in the allowed capture set {} of the self type of class Fuzz
--- [E058] Type Mismatch Error: tests/neg-custom-args/captures/leaked-curried.scala:15:10 -------------------------------
-15 |    class Foo extends Box, Pure: // error
-   |          ^
-   |          illegal inheritance: self type Foo^{io} of class Foo does not conform to self type Pure
-   |          of parent trait Pure
-   |
-   | longer explanation available when compiling with `-explain`
+-- Error: tests/neg-custom-args/captures/leaked-curried.scala:17:20 ----------------------------------------------------
+17 |        () => () => io // error
+   |                    ^^
+   |(io : Cap^) cannot be referenced here; it is not included in the allowed capture set {} of the self type of class Foo

tests/neg-custom-args/captures/leaked-curried.scala

@@ -12,8 +12,8 @@ def main(): Unit =
       self =>
       val get: () ->{} () ->{io} Cap^ =
         () => () => io // error
-    class Foo extends Box, Pure: // error
+    class Foo extends Box, Pure:
       val get: () ->{} () ->{io} Cap^ =
-        () => () => io
+        () => () => io // error
     new Foo
   val bad = leaked.get()().use()  // using a leaked capability