Added tests with two superclasses.

#KT-2776 in progress

compiler/testData/loadJava/kotlinSignature/propagation/return/TwoSuperclassesReturnJavaSubtype.java

@@ -0,0 +1,19 @@
+package test;
+
+import org.jetbrains.annotations.NotNull;
+import java.lang.CharSequence;
+
+import jet.runtime.typeinfo.KotlinSignature;
+
+public interface TwoSuperclassesReturnJavaSubtype {
+    public CharSequence foo();
+
+    public interface Other {
+        @NotNull
+        public CharSequence foo();
+    }
+
+    public interface Sub extends TwoSuperclassesReturnJavaSubtype, Other {
+        public String foo();
+    }
+}

compiler/testData/loadJava/kotlinSignature/propagation/return/TwoSuperclassesReturnJavaSubtype.kt

@@ -0,0 +1,15 @@
+package test
+
+import org.jetbrains.annotations.NotNull
+
+public trait TwoSuperclassesReturnJavaSubtype: Object {
+    public fun foo(): CharSequence?
+
+    public trait Other: Object {
+        public fun foo(): CharSequence
+    }
+
+    public trait Sub: TwoSuperclassesReturnJavaSubtype, Other {
+        override fun foo(): String
+    }
+}

compiler/testData/loadJava/kotlinSignature/propagation/return/TwoSuperclassesReturnJavaSubtype.txt

@@ -0,0 +1,11 @@
+namespace test
+
+public abstract trait test.TwoSuperclassesReturnJavaSubtype : java.lang.Object {
+    public abstract fun foo(): jet.CharSequence?
+    public abstract trait test.TwoSuperclassesReturnJavaSubtype.Other : java.lang.Object {
+        public abstract fun foo(): jet.CharSequence
+    }
+    public abstract trait test.TwoSuperclassesReturnJavaSubtype.Sub : test.TwoSuperclassesReturnJavaSubtype, test.TwoSuperclassesReturnJavaSubtype.Other {
+        public abstract override /*2*/ fun foo(): jet.String
+    }
+}

compiler/testData/loadJava/kotlinSignature/propagation/return/TwoSuperclassesReturnSameJavaType.java

@@ -0,0 +1,19 @@
+package test;
+
+import org.jetbrains.annotations.NotNull;
+import java.lang.CharSequence;
+
+import jet.runtime.typeinfo.KotlinSignature;
+
+public interface TwoSuperclassesReturnSameJavaType {
+    public CharSequence foo();
+
+    public interface Other {
+        @NotNull
+        public CharSequence foo();
+    }
+
+    public interface Sub extends TwoSuperclassesReturnSameJavaType, Other {
+        public CharSequence foo();
+    }
+}

compiler/testData/loadJava/kotlinSignature/propagation/return/TwoSuperclassesReturnSameJavaType.kt

@@ -0,0 +1,15 @@
+package test
+
+import org.jetbrains.annotations.NotNull
+
+public trait TwoSuperclassesReturnSameJavaType: Object {
+    public fun foo(): CharSequence?
+
+    public trait Other: Object {
+        public fun foo(): CharSequence
+    }
+
+    public trait Sub: TwoSuperclassesReturnSameJavaType, Other {
+        override fun foo(): CharSequence
+    }
+}

compiler/testData/loadJava/kotlinSignature/propagation/return/TwoSuperclassesReturnSameJavaType.txt

@@ -0,0 +1,11 @@
+namespace test
+
+public abstract trait test.TwoSuperclassesReturnSameJavaType : java.lang.Object {
+    public abstract fun foo(): jet.CharSequence?
+    public abstract trait test.TwoSuperclassesReturnSameJavaType.Other : java.lang.Object {
+        public abstract fun foo(): jet.CharSequence
+    }
+    public abstract trait test.TwoSuperclassesReturnSameJavaType.Sub : test.TwoSuperclassesReturnSameJavaType, test.TwoSuperclassesReturnSameJavaType.Other {
+        public abstract override /*2*/ fun foo(): jet.CharSequence
+    }
+}