Class can't inherit itself: typechecking error

src/main/java/kc875/ast/visit/TypeCheckVisitor.java

@@ -1040,6 +1040,13 @@ private void collectTauClasses(List<? extends ClassXi> cs) {
         // Initial pass for duplicate classes, fields and methods in this file
         Set<String> classNames = new HashSet<>();
         for (ClassXi c : cs) {
+            // Class can't inherit itself
+            c.getSuperClass().thenDo(sc -> {
+                if (sc.equals(c.getName()))
+                    throw new SemanticError(
+                            "Class can't inherit itself", c.getLocation()
+                    );
+            });
             // Duplicate classes not allowed
             String cName = c.getName();
             if (classNames.contains(cName)) {

tests/pa7-typecheck-tests/a.ixi

@@ -1,5 +1,6 @@
 class A {
     a: int
+    ma()
 }
 
 fa()

tests/pa7-typecheck-tests/class_decl_defn_dont_match_error0.typedsol

@@ -0,0 +1 @@
+3:1 error:Different methods in declaration and definition of class A

tests/pa7-typecheck-tests/class_decl_defn_dont_match_error0.xi

@@ -0,0 +1,8 @@
+use a
+
+// A defines an extra method
+class A {
+    a: int
+    ma() {}
+    extra_method() {}
+}

tests/pa7-typecheck-tests/class_decl_defn_dont_match_error1.typedsol

@@ -0,0 +1 @@
+7:5 error:Function ma already defined

tests/pa7-typecheck-tests/class_decl_defn_dont_match_error1.xi

@@ -0,0 +1,8 @@
+use a
+
+// A provides duplicate methods
+class A {
+    a: int
+    ma() {}
+    ma() {}
+}

tests/pa7-typecheck-tests/class_decl_defn_dont_match_error2.typedsol

@@ -0,0 +1 @@
+6:5 error:Mismatch signatures of overriden function with name ma

tests/pa7-typecheck-tests/class_decl_defn_dont_match_error2.xi

@@ -0,0 +1,7 @@
+use a
+
+// A defines ma with a different signature than the declaration in module a
+class A {
+    a: int
+    ma(p: int) {}
+}

tests/pa7-typecheck-tests/class_decl_defn_dont_match_error3.typedsol

@@ -0,0 +1 @@
+7:1 error:Declaration and definition for class A don't inherit the same class

tests/pa7-typecheck-tests/class_decl_defn_dont_match_error3.xi

@@ -0,0 +1,10 @@
+use a
+
+class B {
+}
+
+// A inherits a class but the declaration doesn't
+class A extends B {
+    a: int
+    ma() {}
+}

tests/pa7-typecheck-tests/class_decl_defn_dont_match_error4.typedsol

@@ -0,0 +1 @@
+7:1 error:Declaration and definition for class B don't inherit the same class

tests/pa7-typecheck-tests/class_decl_defn_dont_match_error4.xi

@@ -0,0 +1,9 @@
+use b
+
+class C {
+}
+
+// B's def inherits C but decl inherits A
+class B extends C {
+    b: int
+}

tests/pa7-typecheck-tests/class_inherit_itself_error.typedsol

@@ -0,0 +1 @@
+1:1 error:Class can't inherit itself

tests/pa7-typecheck-tests/class_inherit_itself_error.xi

@@ -0,0 +1,2 @@
+class B extends B {
+}

tests/pa7-typecheck-tests/class_nested_interface_imports.xi

@@ -13,4 +13,10 @@ fb() {}
 main(args:int[][]) {
     fa()// should've been imported by b
     fb()
+    c: C = new C
+    c.ma()
+    d: D = new D
+    d.ma()
+    a: A = new A
+    a.ma()
 }

tests/pa7-typecheck-tests/xthScript

@@ -36,6 +36,11 @@ xic ("Test --typecheck") "-libpath $(testpath) --typecheck" {
     break_creates_unreachable_stmt.xi;
     break_in_loop_multiple_places.xi;
     break_outside_loop.xi;
+    class_decl_defn_dont_match_error0.xi;
+    class_decl_defn_dont_match_error1.xi;
+    class_decl_defn_dont_match_error2.xi;
+    class_decl_defn_dont_match_error3.xi;
+    class_decl_defn_dont_match_error4.xi;
     class_dup_def.xi;
     class_field_init_by_methods.xi;
     class_field_not_found.xi;
@@ -44,6 +49,7 @@ xic ("Test --typecheck") "-libpath $(testpath) --typecheck" {
     class_implements_interface.xi;
     class_incorrect_override_diff_params.xi;
     class_incorrect_override_diff_ret.xi;
+    class_inherit_itself_error.xi;
     class_method_not_found.xi;
     class_method_shadow_by_method.xi;
     class_method_use_super_method.xi;