diff --git a/ql/src/codeql_ruby/ast/Call.qll b/ql/src/codeql_ruby/ast/Call.qll
index b38b2b37263..366aab182a1 100644
--- a/ql/src/codeql_ruby/ast/Call.qll
+++ b/ql/src/codeql_ruby/ast/Call.qll
@@ -85,6 +85,21 @@ class MethodCall extends Call, TMethodCall {
    */
   Expr getReceiver() { none() }
 
+  /**
+   * Holds if the receiver is `self` or there is no receiver, which has the same
+   * meaning as an explict `self`. For example:
+   *
+   * ```rb
+   * self.foo
+   * foo
+   * ```
+   */
+  predicate receiverIsSelf() {
+    this.getReceiver() instanceof Self
+    or
+    not exists(this.getReceiver())
+  }
+
   /**
    * Gets the name of the method being called. For example, in:
    *
diff --git a/ql/src/codeql_ruby/ast/Module.qll b/ql/src/codeql_ruby/ast/Module.qll
index d449a576e4a..17661c281ba 100644
--- a/ql/src/codeql_ruby/ast/Module.qll
+++ b/ql/src/codeql_ruby/ast/Module.qll
@@ -8,9 +8,18 @@ private import internal.TreeSitter
  * A representation of a run-time `module` or `class` value.
  */
 class Module extends TModule {
-  /** Get a declaration of this module, if any. */
+  /** Gets a declaration of this module, if any. */
   ModuleBase getADeclaration() { result.getModule() = this }
 
+  /** Gets the super class of this module, if any. */
+  Module getSuperClass() { result = getSuperClass(this) }
+
+  /** Gets a `prepend`ed module. */
+  Module getAPrependedModule() { result = getAPrependedModule(this) }
+
+  /** Gets an `include`d module. */
+  Module getAnIncludedModule() { result = getAnIncludedModule(this) }
+
   /** Gets a textual representation of this module. */
   string toString() {
     this = TResolved(result)
diff --git a/ql/src/codeql_ruby/ast/internal/Module.qll b/ql/src/codeql_ruby/ast/internal/Module.qll
index a1f128d0a08..d7708271e11 100644
--- a/ql/src/codeql_ruby/ast/internal/Module.qll
+++ b/ql/src/codeql_ruby/ast/internal/Module.qll
@@ -34,6 +34,58 @@ private module Cached {
       result = scopeAppend(container, n.getName())
     )
   }
+
+  cached
+  Module getSuperClass(Module cls) {
+    cls = TResolved("Object") and result = TResolved("BasicObject")
+    or
+    cls = TResolved("Module") and result = TResolved("Object")
+    or
+    cls = TResolved("Class") and result = TResolved("Module")
+    or
+    not cls = TResolved(builtin()) and
+    (
+      exists(ClassDeclaration d |
+        d = cls.getADeclaration() and
+        result = resolveScopeExpr(d.getSuperclassExpr())
+      )
+      or
+      result = TResolved("Object") and
+      forex(ClassDeclaration d | d = cls.getADeclaration() |
+        not exists(resolveScopeExpr(d.getSuperclassExpr()))
+      )
+    )
+  }
+
+  cached
+  Module getAnIncludedModule(Module m) {
+    m = TResolved("Object") and result = TResolved("Kernel")
+    or
+    exists(IncludeOrPrependCall c |
+      c.getMethodName() = "include" and
+      (
+        m = resolveScopeExpr(c.getReceiver())
+        or
+        m = enclosingModule(c).getModule() and
+        c.receiverIsSelf()
+      ) and
+      result = resolveScopeExpr(c.getAnArgument())
+    )
+  }
+
+  cached
+  Module getAPrependedModule(Module m) {
+    exists(IncludeOrPrependCall c |
+      c.getMethodName() = "prepend" and
+      (
+        m = resolveScopeExpr(c.getReceiver())
+        or
+        m = enclosingModule(c).getModule() and
+        c.receiverIsSelf()
+      ) and
+      result = resolveScopeExpr(c.getAnArgument())
+    )
+  }
 }
 
 import Cached
@@ -242,3 +294,31 @@ private string qualifiedModuleName(string container, string name) {
     container = "Object" and name = result
   )
 }
+
+private Module getAncestors(Module m) {
+  result = m or
+  result = getAncestors(m.getAnIncludedModule()) or
+  result = getAncestors(m.getAPrependedModule())
+}
+
+Method getMethod(TModule owner, string name) {
+  exists(ModuleBase m | m.getModule() = owner and result = m.getMethod(name))
+}
+
+private Method lookupMethod0(Module m, string name) {
+  result = lookupMethod0(m.getAPrependedModule(), name)
+  or
+  not exists(getMethod(getAncestors(m.getAPrependedModule()), name)) and
+  (
+    result = getMethod(m, name)
+    or
+    not exists(getMethod(m, name)) and result = lookupMethod0(m.getAnIncludedModule(), name)
+  )
+}
+
+Method lookupMethod(Module m, string name) {
+  result = lookupMethod0(m, name)
+  or
+  not exists(lookupMethod0(m, name)) and
+  result = lookupMethod(m.getSuperClass(), name)
+}
diff --git a/ql/src/codeql_ruby/controlflow/internal/Cfg.ql b/ql/src/codeql_ruby/controlflow/internal/Cfg.ql
index ded6b103222..a0b0200b346 100644
--- a/ql/src/codeql_ruby/controlflow/internal/Cfg.ql
+++ b/ql/src/codeql_ruby/controlflow/internal/Cfg.ql
@@ -1,5 +1,6 @@
 /**
  * @kind graph
+ * @id rb/test/cfg
  */
 
 import codeql_ruby.CFG
diff --git a/ql/test/library-tests/ast/Ast.ql b/ql/test/library-tests/ast/Ast.ql
index babafaac548..4cd412f83a0 100644
--- a/ql/test/library-tests/ast/Ast.ql
+++ b/ql/test/library-tests/ast/Ast.ql
@@ -1,5 +1,6 @@
 /**
  * @kind graph
+ * @id rb/test/print-ast
  */
 
 import codeql_ruby.printAst
diff --git a/ql/test/library-tests/ast/modules/modules.expected b/ql/test/library-tests/ast/modules/modules.expected
index f7f52051674..61352f7c78e 100644
--- a/ql/test/library-tests/ast/modules/modules.expected
+++ b/ql/test/library-tests/ast/modules/modules.expected
@@ -101,49 +101,3 @@ modulesInModules
 | modules.rb:95:1:99:3 | IncludeTest2 | modules.rb:97:3:98:5 | Z | Z |
 | modules.rb:101:1:105:3 | PrependTest | modules.rb:103:3:104:5 | Y | Y |
 | modules.rb:107:1:110:3 | MM | modules.rb:108:3:109:5 | MM | MM |
-moduleTypes
-| classes.rb:2:1:56:3 | classes.rb | file://:0:0:0:0 | Object |
-| classes.rb:3:1:4:3 | Foo | modules.rb:4:1:24:3 | Foo |
-| classes.rb:7:1:8:3 | Bar | modules.rb:37:1:46:3 | Bar |
-| classes.rb:11:1:12:3 | Baz | classes.rb:11:1:12:3 | Baz |
-| classes.rb:15:1:15:20 | MyModule | classes.rb:15:1:15:20 | MyModule |
-| classes.rb:16:1:17:3 | MyClass | classes.rb:16:1:17:3 | MyModule::MyClass |
-| classes.rb:20:1:37:3 | Wibble | classes.rb:20:1:37:3 | Wibble |
-| classes.rb:32:3:33:5 | ClassInWibble | classes.rb:32:3:33:5 | Wibble::ClassInWibble |
-| classes.rb:35:3:36:5 | ModuleInWibble | classes.rb:35:3:36:5 | Wibble::ModuleInWibble |
-| classes.rb:55:1:56:3 | MyClassInGlobalScope | classes.rb:55:1:56:3 | MyClassInGlobalScope |
-| modules.rb:1:1:2:3 | Empty | modules.rb:1:1:2:3 | Empty |
-| modules.rb:1:1:122:1 | modules.rb | file://:0:0:0:0 | Object |
-| modules.rb:4:1:24:3 | Foo | modules.rb:4:1:24:3 | Foo |
-| modules.rb:5:3:14:5 | Bar | modules.rb:5:3:14:5 | Foo::Bar |
-| modules.rb:6:5:7:7 | ClassInFooBar | modules.rb:6:5:7:7 | Foo::Bar::ClassInFooBar |
-| modules.rb:19:3:20:5 | ClassInFoo | modules.rb:19:3:20:5 | Foo::ClassInFoo |
-| modules.rb:26:1:35:3 | Foo | modules.rb:4:1:24:3 | Foo |
-| modules.rb:30:3:31:5 | ClassInAnotherDefinitionOfFoo | modules.rb:30:3:31:5 | Foo::ClassInAnotherDefinitionOfFoo |
-| modules.rb:37:1:46:3 | Bar | modules.rb:37:1:46:3 | Bar |
-| modules.rb:48:1:57:3 | Bar | modules.rb:5:3:14:5 | Foo::Bar |
-| modules.rb:49:3:50:5 | ClassInAnotherDefinitionOfFooBar | modules.rb:49:3:50:5 | Foo::Bar::ClassInAnotherDefinitionOfFooBar |
-| modules.rb:60:1:61:3 | MyModuleInGlobalScope | modules.rb:60:1:61:3 | MyModuleInGlobalScope |
-| modules.rb:63:1:81:3 | Test | modules.rb:63:1:81:3 | Test |
-| modules.rb:65:3:68:5 | Foo1 | modules.rb:65:3:68:5 | Test::Foo1 |
-| modules.rb:66:5:67:7 | Bar | modules.rb:66:5:67:7 | Test::Foo1::Bar |
-| modules.rb:70:3:74:5 | Foo2 | modules.rb:70:3:74:5 | Test::Foo2 |
-| modules.rb:71:5:71:19 | Foo2 | modules.rb:71:5:71:19 | Test::Foo2::Foo2 |
-| modules.rb:72:5:73:7 | Bar | modules.rb:72:5:73:7 | Test::Foo2::Foo2::Bar |
-| modules.rb:76:3:80:5 | Foo3 | modules.rb:76:3:80:5 | Test::Foo3 |
-| modules.rb:78:5:79:7 | Bar | modules.rb:37:1:46:3 | Bar |
-| modules.rb:83:1:86:3 | Other | modules.rb:83:1:86:3 | Other |
-| modules.rb:84:3:85:5 | Foo1 | modules.rb:84:3:85:5 | Other::Foo1 |
-| modules.rb:88:1:93:3 | IncludeTest | modules.rb:88:1:93:3 | IncludeTest |
-| modules.rb:91:3:92:5 | Y | modules.rb:91:3:92:5 | Test::Foo1::Y |
-| modules.rb:95:1:99:3 | IncludeTest2 | modules.rb:95:1:99:3 | IncludeTest2 |
-| modules.rb:97:3:98:5 | Z | modules.rb:97:3:98:5 | Test::Foo1::Z |
-| modules.rb:101:1:105:3 | PrependTest | modules.rb:101:1:105:3 | PrependTest |
-| modules.rb:103:3:104:5 | Y | modules.rb:103:3:104:5 | Test::Foo2::Y |
-| modules.rb:107:1:110:3 | MM | modules.rb:107:1:110:3 | MM |
-| modules.rb:108:3:109:5 | MM | modules.rb:108:3:109:5 | MM::MM |
-| modules.rb:112:1:113:3 | YY | modules.rb:112:1:113:3 | YY |
-| modules.rb:115:1:118:3 | XX | modules.rb:115:1:118:3 | XX |
-| modules.rb:116:7:117:9 | YY | modules.rb:116:7:117:9 | XX::YY |
-| modules.rb:120:1:121:3 | Baz | modules.rb:120:1:121:3 | Test::Foo1::Bar::Baz |
-| toplevel.rb:1:1:5:23 | toplevel.rb | file://:0:0:0:0 | Object |
diff --git a/ql/test/library-tests/ast/modules/modules.ql b/ql/test/library-tests/ast/modules/modules.ql
index 21adb23e633..9ed9c7b4fa2 100644
--- a/ql/test/library-tests/ast/modules/modules.ql
+++ b/ql/test/library-tests/ast/modules/modules.ql
@@ -23,5 +23,3 @@ query predicate classesInModules(ModuleDeclaration mod, ClassDeclaration klass,
 query predicate modulesInModules(ModuleDeclaration mod, ModuleDeclaration child, string name) {
   child = mod.getModule(name)
 }
-
-query predicate moduleTypes(ModuleBase def, Module type) { type = def.getModule() }
diff --git a/ql/test/library-tests/modules/ancestors.expected b/ql/test/library-tests/modules/ancestors.expected
new file mode 100644
index 00000000000..4d00bf4dd04
--- /dev/null
+++ b/ql/test/library-tests/modules/ancestors.expected
@@ -0,0 +1,96 @@
+#-----| Object
+#-----| include -> Kernel
+#-----| super -> BasicObject
+
+#-----| Class
+#-----| super -> Module
+
+#-----| Kernel
+
+#-----| Module
+#-----| super -> Object
+
+#-----| BasicObject
+
+hello.rb:
+#    1| EnglishWords
+
+#   11| Greeting
+#-----| super -> Object
+#-----| include -> EnglishWords
+
+#   18| HelloWorld
+#-----| super -> Greeting
+
+modules.rb:
+#    1| Empty
+
+#    4| Foo
+
+#   37| Bar
+#-----| super -> Object
+
+#   60| MyModuleInGlobalScope
+
+#   63| Test
+
+#   83| Other
+
+#   88| IncludeTest
+#-----| include -> Test
+
+#   95| IncludeTest2
+#-----| include -> Test
+
+#  101| PrependTest
+#-----| prepend -> Test
+
+#  107| MM
+
+#  112| YY
+#-----| super -> Object
+
+#  115| XX
+
+#    5| Foo::Bar
+
+#   19| Foo::ClassInFoo
+#-----| super -> Object
+
+#   30| Foo::ClassInAnotherDefinitionOfFoo
+#-----| super -> Object
+
+#   65| Test::Foo1
+
+#   70| Test::Foo2
+
+#   76| Test::Foo3
+
+#   84| Other::Foo1
+
+#  116| XX::YY
+#-----| super -> YY
+
+#    6| Foo::Bar::ClassInFooBar
+#-----| super -> Object
+
+#   71| Test::Foo2::Foo2
+
+#  108| MM::MM
+
+#   49| Foo::Bar::ClassInAnotherDefinitionOfFooBar
+#-----| super -> Object
+
+#   66| Test::Foo1::Bar
+#-----| super -> Object
+
+#   91| Test::Foo1::Y
+
+#   97| Test::Foo1::Z
+
+#  103| Test::Foo2::Y
+
+#   72| Test::Foo2::Foo2::Bar
+#-----| super -> Object
+
+#  120| Test::Foo1::Bar::Baz
diff --git a/ql/test/library-tests/modules/ancestors.ql b/ql/test/library-tests/modules/ancestors.ql
new file mode 100644
index 00000000000..897ddf94f35
--- /dev/null
+++ b/ql/test/library-tests/modules/ancestors.ql
@@ -0,0 +1,21 @@
+/**
+ * @kind graph
+ * @id rb/test/ancestors
+ */
+
+import ruby
+
+query predicate nodes(Module node, string key, string value) {
+  key = "semmle.label" and value = node.toString()
+}
+
+query predicate edges(Module source, Module target, string key, string value) {
+  key = "semmle.label" and
+  (
+    target = source.getSuperClass() and value = "super"
+    or
+    target = source.getAPrependedModule() and value = "prepend"
+    or
+    target = source.getAnIncludedModule() and value = "include"
+  )
+}
diff --git a/ql/test/library-tests/modules/hello.rb b/ql/test/library-tests/modules/hello.rb
new file mode 100644
index 00000000000..1cfa0f7e4f3
--- /dev/null
+++ b/ql/test/library-tests/modules/hello.rb
@@ -0,0 +1,22 @@
+module EnglishWords
+    def hello
+        return "hello"
+    end
+    def world
+        return "world"
+    end
+end
+
+
+class Greeting
+    include EnglishWords
+    def message 
+        return hello
+    end
+end
+
+class HelloWorld < Greeting
+    def message
+        return super + " " + world + "!"
+    end
+end
\ No newline at end of file
diff --git a/ql/test/library-tests/modules/methods.expected b/ql/test/library-tests/modules/methods.expected
new file mode 100644
index 00000000000..1a745517cfd
--- /dev/null
+++ b/ql/test/library-tests/modules/methods.expected
@@ -0,0 +1,26 @@
+getMethod
+| hello.rb:1:1:8:3 | EnglishWords | hello | hello.rb:2:5:4:7 | hello |
+| hello.rb:1:1:8:3 | EnglishWords | world | hello.rb:5:5:7:7 | world |
+| hello.rb:11:1:16:3 | Greeting | message | hello.rb:13:5:15:7 | message |
+| hello.rb:18:1:22:3 | HelloWorld | message | hello.rb:19:5:21:7 | message |
+| modules.rb:4:1:24:3 | Foo | method_in_another_definition_of_foo | modules.rb:27:3:28:5 | method_in_another_definition_of_foo |
+| modules.rb:4:1:24:3 | Foo | method_in_foo | modules.rb:16:3:17:5 | method_in_foo |
+| modules.rb:5:3:14:5 | Foo::Bar | method_in_another_definition_of_foo_bar | modules.rb:52:3:53:5 | method_in_another_definition_of_foo_bar |
+| modules.rb:5:3:14:5 | Foo::Bar | method_in_foo_bar | modules.rb:9:5:10:7 | method_in_foo_bar |
+| modules.rb:37:1:46:3 | Bar | method_a | modules.rb:38:3:39:5 | method_a |
+| modules.rb:37:1:46:3 | Bar | method_b | modules.rb:41:3:42:5 | method_b |
+lookupMethod
+| hello.rb:1:1:8:3 | EnglishWords | hello | hello.rb:2:5:4:7 | hello |
+| hello.rb:1:1:8:3 | EnglishWords | world | hello.rb:5:5:7:7 | world |
+| hello.rb:11:1:16:3 | Greeting | hello | hello.rb:2:5:4:7 | hello |
+| hello.rb:11:1:16:3 | Greeting | message | hello.rb:13:5:15:7 | message |
+| hello.rb:11:1:16:3 | Greeting | world | hello.rb:5:5:7:7 | world |
+| hello.rb:18:1:22:3 | HelloWorld | hello | hello.rb:2:5:4:7 | hello |
+| hello.rb:18:1:22:3 | HelloWorld | message | hello.rb:19:5:21:7 | message |
+| hello.rb:18:1:22:3 | HelloWorld | world | hello.rb:5:5:7:7 | world |
+| modules.rb:4:1:24:3 | Foo | method_in_another_definition_of_foo | modules.rb:27:3:28:5 | method_in_another_definition_of_foo |
+| modules.rb:4:1:24:3 | Foo | method_in_foo | modules.rb:16:3:17:5 | method_in_foo |
+| modules.rb:5:3:14:5 | Foo::Bar | method_in_another_definition_of_foo_bar | modules.rb:52:3:53:5 | method_in_another_definition_of_foo_bar |
+| modules.rb:5:3:14:5 | Foo::Bar | method_in_foo_bar | modules.rb:9:5:10:7 | method_in_foo_bar |
+| modules.rb:37:1:46:3 | Bar | method_a | modules.rb:38:3:39:5 | method_a |
+| modules.rb:37:1:46:3 | Bar | method_b | modules.rb:41:3:42:5 | method_b |
diff --git a/ql/test/library-tests/modules/methods.ql b/ql/test/library-tests/modules/methods.ql
new file mode 100644
index 00000000000..323a4c61476
--- /dev/null
+++ b/ql/test/library-tests/modules/methods.ql
@@ -0,0 +1,6 @@
+import ruby
+import codeql_ruby.ast.internal.Module as M
+
+query MethodBase getMethod(Module m, string name) { result = M::getMethod(m, name) }
+
+query MethodBase lookupMethod(Module m, string name) { result = M::lookupMethod(m, name) }
diff --git a/ql/test/library-tests/modules/modules.expected b/ql/test/library-tests/modules/modules.expected
new file mode 100644
index 00000000000..fc802f224d7
--- /dev/null
+++ b/ql/test/library-tests/modules/modules.expected
@@ -0,0 +1,100 @@
+getModule
+| file://:0:0:0:0 | BasicObject |
+| file://:0:0:0:0 | Class |
+| file://:0:0:0:0 | Kernel |
+| file://:0:0:0:0 | Module |
+| file://:0:0:0:0 | Object |
+| hello.rb:1:1:8:3 | EnglishWords |
+| hello.rb:11:1:16:3 | Greeting |
+| hello.rb:18:1:22:3 | HelloWorld |
+| modules.rb:1:1:2:3 | Empty |
+| modules.rb:4:1:24:3 | Foo |
+| modules.rb:5:3:14:5 | Foo::Bar |
+| modules.rb:6:5:7:7 | Foo::Bar::ClassInFooBar |
+| modules.rb:19:3:20:5 | Foo::ClassInFoo |
+| modules.rb:30:3:31:5 | Foo::ClassInAnotherDefinitionOfFoo |
+| modules.rb:37:1:46:3 | Bar |
+| modules.rb:49:3:50:5 | Foo::Bar::ClassInAnotherDefinitionOfFooBar |
+| modules.rb:60:1:61:3 | MyModuleInGlobalScope |
+| modules.rb:63:1:81:3 | Test |
+| modules.rb:65:3:68:5 | Test::Foo1 |
+| modules.rb:66:5:67:7 | Test::Foo1::Bar |
+| modules.rb:70:3:74:5 | Test::Foo2 |
+| modules.rb:71:5:71:19 | Test::Foo2::Foo2 |
+| modules.rb:72:5:73:7 | Test::Foo2::Foo2::Bar |
+| modules.rb:76:3:80:5 | Test::Foo3 |
+| modules.rb:83:1:86:3 | Other |
+| modules.rb:84:3:85:5 | Other::Foo1 |
+| modules.rb:88:1:93:3 | IncludeTest |
+| modules.rb:91:3:92:5 | Test::Foo1::Y |
+| modules.rb:95:1:99:3 | IncludeTest2 |
+| modules.rb:97:3:98:5 | Test::Foo1::Z |
+| modules.rb:101:1:105:3 | PrependTest |
+| modules.rb:103:3:104:5 | Test::Foo2::Y |
+| modules.rb:107:1:110:3 | MM |
+| modules.rb:108:3:109:5 | MM::MM |
+| modules.rb:112:1:113:3 | YY |
+| modules.rb:115:1:118:3 | XX |
+| modules.rb:116:7:117:9 | XX::YY |
+| modules.rb:120:1:121:3 | Test::Foo1::Bar::Baz |
+getADeclaration
+| file://:0:0:0:0 | Object | hello.rb:1:1:22:3 | hello.rb |
+| file://:0:0:0:0 | Object | modules.rb:1:1:122:1 | modules.rb |
+| hello.rb:1:1:8:3 | EnglishWords | hello.rb:1:1:8:3 | EnglishWords |
+| hello.rb:11:1:16:3 | Greeting | hello.rb:11:1:16:3 | Greeting |
+| hello.rb:18:1:22:3 | HelloWorld | hello.rb:18:1:22:3 | HelloWorld |
+| modules.rb:1:1:2:3 | Empty | modules.rb:1:1:2:3 | Empty |
+| modules.rb:4:1:24:3 | Foo | modules.rb:4:1:24:3 | Foo |
+| modules.rb:4:1:24:3 | Foo | modules.rb:26:1:35:3 | Foo |
+| modules.rb:5:3:14:5 | Foo::Bar | modules.rb:5:3:14:5 | Bar |
+| modules.rb:5:3:14:5 | Foo::Bar | modules.rb:48:1:57:3 | Bar |
+| modules.rb:6:5:7:7 | Foo::Bar::ClassInFooBar | modules.rb:6:5:7:7 | ClassInFooBar |
+| modules.rb:19:3:20:5 | Foo::ClassInFoo | modules.rb:19:3:20:5 | ClassInFoo |
+| modules.rb:30:3:31:5 | Foo::ClassInAnotherDefinitionOfFoo | modules.rb:30:3:31:5 | ClassInAnotherDefinitionOfFoo |
+| modules.rb:37:1:46:3 | Bar | modules.rb:37:1:46:3 | Bar |
+| modules.rb:37:1:46:3 | Bar | modules.rb:78:5:79:7 | Bar |
+| modules.rb:49:3:50:5 | Foo::Bar::ClassInAnotherDefinitionOfFooBar | modules.rb:49:3:50:5 | ClassInAnotherDefinitionOfFooBar |
+| modules.rb:60:1:61:3 | MyModuleInGlobalScope | modules.rb:60:1:61:3 | MyModuleInGlobalScope |
+| modules.rb:63:1:81:3 | Test | modules.rb:63:1:81:3 | Test |
+| modules.rb:65:3:68:5 | Test::Foo1 | modules.rb:65:3:68:5 | Foo1 |
+| modules.rb:66:5:67:7 | Test::Foo1::Bar | modules.rb:66:5:67:7 | Bar |
+| modules.rb:70:3:74:5 | Test::Foo2 | modules.rb:70:3:74:5 | Foo2 |
+| modules.rb:71:5:71:19 | Test::Foo2::Foo2 | modules.rb:71:5:71:19 | Foo2 |
+| modules.rb:72:5:73:7 | Test::Foo2::Foo2::Bar | modules.rb:72:5:73:7 | Bar |
+| modules.rb:76:3:80:5 | Test::Foo3 | modules.rb:76:3:80:5 | Foo3 |
+| modules.rb:83:1:86:3 | Other | modules.rb:83:1:86:3 | Other |
+| modules.rb:84:3:85:5 | Other::Foo1 | modules.rb:84:3:85:5 | Foo1 |
+| modules.rb:88:1:93:3 | IncludeTest | modules.rb:88:1:93:3 | IncludeTest |
+| modules.rb:91:3:92:5 | Test::Foo1::Y | modules.rb:91:3:92:5 | Y |
+| modules.rb:95:1:99:3 | IncludeTest2 | modules.rb:95:1:99:3 | IncludeTest2 |
+| modules.rb:97:3:98:5 | Test::Foo1::Z | modules.rb:97:3:98:5 | Z |
+| modules.rb:101:1:105:3 | PrependTest | modules.rb:101:1:105:3 | PrependTest |
+| modules.rb:103:3:104:5 | Test::Foo2::Y | modules.rb:103:3:104:5 | Y |
+| modules.rb:107:1:110:3 | MM | modules.rb:107:1:110:3 | MM |
+| modules.rb:108:3:109:5 | MM::MM | modules.rb:108:3:109:5 | MM |
+| modules.rb:112:1:113:3 | YY | modules.rb:112:1:113:3 | YY |
+| modules.rb:115:1:118:3 | XX | modules.rb:115:1:118:3 | XX |
+| modules.rb:116:7:117:9 | XX::YY | modules.rb:116:7:117:9 | YY |
+| modules.rb:120:1:121:3 | Test::Foo1::Bar::Baz | modules.rb:120:1:121:3 | Baz |
+getSuperClass
+| file://:0:0:0:0 | Class | file://:0:0:0:0 | Module |
+| file://:0:0:0:0 | Module | file://:0:0:0:0 | Object |
+| file://:0:0:0:0 | Object | file://:0:0:0:0 | BasicObject |
+| hello.rb:11:1:16:3 | Greeting | file://:0:0:0:0 | Object |
+| hello.rb:18:1:22:3 | HelloWorld | hello.rb:11:1:16:3 | Greeting |
+| modules.rb:6:5:7:7 | Foo::Bar::ClassInFooBar | file://:0:0:0:0 | Object |
+| modules.rb:19:3:20:5 | Foo::ClassInFoo | file://:0:0:0:0 | Object |
+| modules.rb:30:3:31:5 | Foo::ClassInAnotherDefinitionOfFoo | file://:0:0:0:0 | Object |
+| modules.rb:37:1:46:3 | Bar | file://:0:0:0:0 | Object |
+| modules.rb:49:3:50:5 | Foo::Bar::ClassInAnotherDefinitionOfFooBar | file://:0:0:0:0 | Object |
+| modules.rb:66:5:67:7 | Test::Foo1::Bar | file://:0:0:0:0 | Object |
+| modules.rb:72:5:73:7 | Test::Foo2::Foo2::Bar | file://:0:0:0:0 | Object |
+| modules.rb:112:1:113:3 | YY | file://:0:0:0:0 | Object |
+| modules.rb:116:7:117:9 | XX::YY | modules.rb:112:1:113:3 | YY |
+getAPrependedModule
+| modules.rb:101:1:105:3 | PrependTest | modules.rb:63:1:81:3 | Test |
+getAnIncludedModule
+| file://:0:0:0:0 | Object | file://:0:0:0:0 | Kernel |
+| hello.rb:11:1:16:3 | Greeting | hello.rb:1:1:8:3 | EnglishWords |
+| modules.rb:88:1:93:3 | IncludeTest | modules.rb:63:1:81:3 | Test |
+| modules.rb:95:1:99:3 | IncludeTest2 | modules.rb:63:1:81:3 | Test |
diff --git a/ql/test/library-tests/modules/modules.ql b/ql/test/library-tests/modules/modules.ql
new file mode 100644
index 00000000000..a29d2e93756
--- /dev/null
+++ b/ql/test/library-tests/modules/modules.ql
@@ -0,0 +1,11 @@
+import ruby
+
+query Module getModule() { any() }
+
+query ModuleBase getADeclaration(Module m) { result = m.getADeclaration() }
+
+query Module getSuperClass(Module m) { result = m.getSuperClass() }
+
+query Module getAPrependedModule(Module m) { result = m.getAPrependedModule() }
+
+query Module getAnIncludedModule(Module m) { result = m.getAnIncludedModule() }
diff --git a/ql/test/library-tests/modules/modules.rb b/ql/test/library-tests/modules/modules.rb
new file mode 100644
index 00000000000..8287b0a1bc4
--- /dev/null
+++ b/ql/test/library-tests/modules/modules.rb
@@ -0,0 +1,122 @@
+module Empty
+end
+
+module Foo
+  module Bar
+    class ClassInFooBar
+    end
+
+    def method_in_foo_bar
+    end
+
+    puts 'module Foo::Bar'
+    $global_var = 0
+  end
+
+  def method_in_foo
+  end
+
+  class ClassInFoo
+  end
+
+  puts 'module Foo'
+  $global_var = 1
+end
+
+module Foo
+  def method_in_another_definition_of_foo
+  end
+
+  class ClassInAnotherDefinitionOfFoo
+  end
+
+  puts 'module Foo again'
+  $global_var = 2
+end
+
+module Bar
+  def method_a
+  end
+
+  def method_b
+  end
+
+  puts 'module Bar'
+  $global_var = 3
+end
+
+module Foo::Bar
+  class ClassInAnotherDefinitionOfFooBar
+  end
+
+  def method_in_another_definition_of_foo_bar
+  end
+
+  puts 'module Foo::Bar again'
+  $global_var = 4
+end
+
+# a module where the name is a scope resolution using the global scope
+module ::MyModuleInGlobalScope
+end
+
+module Test
+
+  module Foo1
+    class Foo1::Bar
+    end
+  end
+
+  module Foo2
+    module Foo2 end
+    class Foo2::Bar
+    end
+  end
+  
+  module Foo3
+    Foo3 = Object
+    class Foo3::Bar
+    end
+  end
+end
+
+module Other
+  module Foo1
+  end
+end
+
+module IncludeTest
+  include ::Test
+  Object.module_eval { prepend Other }
+  module Foo1::Y
+  end
+end
+
+module IncludeTest2
+  include Test
+  module Foo1::Z
+  end
+end
+
+module PrependTest
+  prepend ::Test
+  module Foo2::Y
+  end
+end
+
+module MM
+  module MM::MM
+  end
+end
+
+class YY
+end
+
+module XX
+      class YY < YY
+      end
+end
+
+module Test::Foo1::Bar::Baz
+end
+
diff --git a/ql/test/library-tests/modules/superclasses.expected b/ql/test/library-tests/modules/superclasses.expected
new file mode 100644
index 00000000000..38c127ff92b
--- /dev/null
+++ b/ql/test/library-tests/modules/superclasses.expected
@@ -0,0 +1,91 @@
+#-----| Object
+#-----|  -> BasicObject
+
+#-----| Class
+#-----|  -> Module
+
+#-----| Kernel
+
+#-----| Module
+#-----|  -> Object
+
+#-----| BasicObject
+
+hello.rb:
+#    1| EnglishWords
+
+#   11| Greeting
+#-----|  -> Object
+
+#   18| HelloWorld
+#-----|  -> Greeting
+
+modules.rb:
+#    1| Empty
+
+#    4| Foo
+
+#   37| Bar
+#-----|  -> Object
+
+#   60| MyModuleInGlobalScope
+
+#   63| Test
+
+#   83| Other
+
+#   88| IncludeTest
+
+#   95| IncludeTest2
+
+#  101| PrependTest
+
+#  107| MM
+
+#  112| YY
+#-----|  -> Object
+
+#  115| XX
+
+#    5| Foo::Bar
+
+#   19| Foo::ClassInFoo
+#-----|  -> Object
+
+#   30| Foo::ClassInAnotherDefinitionOfFoo
+#-----|  -> Object
+
+#   65| Test::Foo1
+
+#   70| Test::Foo2
+
+#   76| Test::Foo3
+
+#   84| Other::Foo1
+
+#  116| XX::YY
+#-----|  -> YY
+
+#    6| Foo::Bar::ClassInFooBar
+#-----|  -> Object
+
+#   71| Test::Foo2::Foo2
+
+#  108| MM::MM
+
+#   49| Foo::Bar::ClassInAnotherDefinitionOfFooBar
+#-----|  -> Object
+
+#   66| Test::Foo1::Bar
+#-----|  -> Object
+
+#   91| Test::Foo1::Y
+
+#   97| Test::Foo1::Z
+
+#  103| Test::Foo2::Y
+
+#   72| Test::Foo2::Foo2::Bar
+#-----|  -> Object
+
+#  120| Test::Foo1::Bar::Baz
diff --git a/ql/test/library-tests/modules/superclasses.ql b/ql/test/library-tests/modules/superclasses.ql
new file mode 100644
index 00000000000..d2141aa38ff
--- /dev/null
+++ b/ql/test/library-tests/modules/superclasses.ql
@@ -0,0 +1,12 @@
+/**
+ * @kind graph
+ * @id rb/test/supertypes
+ */
+
+import ruby
+
+query predicate nodes(Module node, string key, string value) {
+  key = "semmle.label" and value = node.toString()
+}
+
+query predicate edges(Module source, Module target) { target = source.getSuperClass() }