Test for #6804

compiler-java/test/src/com/redhat/ceylon/compiler/java/test/structure/StructureTests.java

@@ -480,6 +480,11 @@ public void testKlsBug6157(){
         compareWithJavaSource("klass/Bug6157");
     }
 
+    @Test
+    public void testKlsIterableSequence(){
+        compareWithJavaSource("klass/IterableSequence");
+    }
+
     //
     // Methods
 

compiler-java/test/src/com/redhat/ceylon/compiler/java/test/structure/klass/IterableSequence.ceylon

@@ -0,0 +1,143 @@
+interface IterableSequence <out Element=Anything, 
+                          out Absent=Null>
+        given Absent satisfies Null {
+    @nailed:"Sequential<? extends Element>"
+    shared default [Element+] | []&Iterable<Element,Absent> sequence()
+        => nothing;
+}
+// check mixin
+class IterableSequenceMixin<out Element,out Absent=Null>() 
+        satisfies IterableSequence<Element> 
+        given Absent satisfies Null {
+}
+// check overriding
+class IterableSequenceOverride<out Element,out Absent=Null>() 
+        satisfies IterableSequence<Element> 
+        given Absent satisfies Null {
+    shared actual [Element+] | []&Iterable<Element,Absent> sequence()
+        => nothing;
+}
+// check overriding+return type refinement
+class IterableSequenceRefine<out Element,out Absent=Null>()
+        satisfies IterableSequence<Element> 
+        given Absent satisfies Null {
+    shared actual [Element,Element] sequence()
+            => nothing;
+}
+void iterableSequence<Element>() {
+    // callsites
+    IterableSequence<Element,Null> possEmpty = nothing;
+    IterableSequence<Element,Nothing> defNonempty = nothing;
+    IterableSequence<Nothing,Nothing> defEmpty1 = nothing;
+    IterableSequence<Nothing,Null> defEmpty2 = nothing;
+
+    // positional args call sites
+    []|[Element+] x1 = possEmpty.sequence();
+    [Element+] x2 = defNonempty.sequence();
+    [] x3 = defEmpty1.sequence();
+    [] x4 = defEmpty2.sequence();
+
+    // name args call sites
+    []|[Element+] y1 = possEmpty.sequence{};
+    [Element+] y2 = defNonempty.sequence{};
+    [] y3 = defEmpty1.sequence{};
+    [] y4 = defEmpty2.sequence{};
+
+    // method ref
+    <[]|[Element+]>() z1 = possEmpty.sequence;
+    [Element+]() z2 = defNonempty.sequence;
+    []() z3 = defEmpty1.sequence;
+    []() z4 = defEmpty2.sequence;
+    []|[Element+] z1c = z1();
+    [Element+] z2c = z2();
+    [] z3c = z3();
+    [] z4c = z4();
+
+    // static ref callsites
+    <[Element+]|[]>()(IterableSequence<Element,Null>) a1 = IterableSequence<Element,Null>.sequence;
+    [Element+]()(IterableSequence<Element,Nothing>) a2 = IterableSequence<Element,Nothing>.sequence;
+    [Nothing+]()(IterableSequence<Nothing,Nothing>) a3 = IterableSequence<Nothing,Nothing>.sequence;
+    []()(IterableSequence<Nothing,Null>) a4 = IterableSequence<Nothing,Null>.sequence;
+    [Element+]|[] a1c = a1(possEmpty)();
+    [Element+] a2c = a2(defNonempty)();
+    [] a3c = a3(defEmpty1)();
+    [] a4c = a4(defEmpty2)();
+
+    // TODO metamodel refs
+
+    // TODO plus subclasses (with and without refinement)
+}
+void iterableSequenceOverride<Element>() {
+    // callsites
+    IterableSequenceOverride<Element,Null> possEmpty = nothing;
+    IterableSequenceOverride<Element,Nothing> defNonempty = nothing;
+    IterableSequenceOverride<Nothing,Nothing> defEmpty1 = nothing;
+    IterableSequenceOverride<Nothing,Null> defEmpty2 = nothing;
+
+    // positional args call sites
+    []|[Element+] x1 = possEmpty.sequence();
+    [Element+] x2 = defNonempty.sequence();
+    [] x3 = defEmpty1.sequence();
+    [] x4 = defEmpty2.sequence();
+
+    // name args call sites
+    []|[Element+] y1 = possEmpty.sequence{};
+    [Element+] y2 = defNonempty.sequence{};
+    [] y3 = defEmpty1.sequence{};
+    [] y4 = defEmpty2.sequence{};
+
+    // method ref
+            <[]|[Element+]>() z1 = possEmpty.sequence;
+    [Element+]() z2 = defNonempty.sequence;
+    []() z3 = defEmpty1.sequence;
+    []() z4 = defEmpty2.sequence;
+
+    // static ref callsites
+    <[Element+]|[]>()(IterableSequenceOverride<Element,Null>) a1 = IterableSequenceOverride<Element,Null>.sequence;
+    [Element+]()(IterableSequenceOverride<Element,Nothing>) a2 = IterableSequenceOverride<Element,Nothing>.sequence;
+    [Nothing+]()(IterableSequenceOverride<Nothing,Nothing>) a3 = IterableSequenceOverride<Nothing,Nothing>.sequence;
+    []()(IterableSequenceOverride<Nothing,Null>) a4 = IterableSequenceOverride<Nothing,Null>.sequence;
+
+    // TODO metamodel refs
+
+    // TODO plus subclasses (with and without refinement)
+}
+void iterableSequenceRefine<Element>() {
+    // callsites
+    IterableSequenceRefine<Element,Null> possEmpty = nothing;
+    IterableSequenceRefine<Element,Nothing> defNonempty = nothing;
+    IterableSequenceRefine<Nothing,Nothing> defEmpty1 = nothing;
+    IterableSequenceRefine<Nothing,Null> defEmpty2 = nothing;
+
+    // positional args call sites
+    []|[Element+] x1 = possEmpty.sequence();
+    [Element+] x2 = defNonempty.sequence();
+    [] x3 = defEmpty1.sequence();
+    [] x4 = defEmpty2.sequence();
+
+    // name args call sites
+    []|[Element+] y1 = possEmpty.sequence{};
+    [Element+] y2 = defNonempty.sequence{};
+    [] y3 = defEmpty1.sequence{};
+    [] y4 = defEmpty2.sequence{};
+
+    // method ref
+    <[]|[Element+]>() z1 = possEmpty.sequence;
+    [Element+]() z2 = defNonempty.sequence;
+    []() z3 = defEmpty1.sequence;
+    []() z4 = defEmpty2.sequence;
+
+    // static ref callsites
+    <[Element+]|[]>()(IterableSequenceRefine<Element,Null>) a1 = IterableSequenceRefine<Element,Null>.sequence;
+    [Element+]()(IterableSequenceRefine<Element,Nothing>) a2 = IterableSequenceRefine<Element,Nothing>.sequence;
+    [Nothing+]()(IterableSequenceRefine<Nothing,Nothing>) a3 = IterableSequenceRefine<Nothing,Nothing>.sequence;
+    []()(IterableSequenceRefine<Nothing,Null>) a4 = IterableSequenceRefine<Nothing,Null>.sequence;
+
+    // TODO metamodel refs
+
+    // TODO plus subclasses (with and without refinement)
+}
+
+abstract class IterableSequenceAbstract() 
+        satisfies IterableSequence<Character> {
+}