C#: Move TypeRefs into a separate file and import it privately. Reorder imports into alphabetical order.

csharp/ql/src/semmle/code/csharp/AnnotatedType.qll

@@ -7,6 +7,7 @@
  */
 
 import csharp
+private import TypeRef
 
 private module Annotations {
   newtype TAnnotation =

csharp/ql/src/semmle/code/csharp/Attribute.qll

@@ -4,6 +4,7 @@
 
 import Type
 private import semmle.code.csharp.ExprOrStmtParent
+private import TypeRef
 
 /**
  * An element that can have attributes. Either an assembly (`Assembly`), a field (`Field`),

csharp/ql/src/semmle/code/csharp/Callable.qll

@@ -3,13 +3,14 @@
  * such as methods and operators.
  */
 
-import Type
 import Member
 import Stmt
+import Type
 import exprs.Call
 private import dotnet
 private import semmle.code.csharp.ExprOrStmtParent
 private import semmle.code.csharp.metrics.Complexity
+private import TypeRef
 
 /**
  * An element that can be called.

csharp/ql/src/semmle/code/csharp/Event.qll

@@ -4,6 +4,7 @@
 
 import Member
 import Type
+private import TypeRef
 
 /**
  * An event, for example `E` on line 3 in

csharp/ql/src/semmle/code/csharp/Generics.qll

@@ -16,6 +16,7 @@
 import Location
 import Namespace
 private import dotnet
+private import TypeRef
 
 /**
  * A generic declaration. Either an unbound generic (`UnboundGeneric`) or a

csharp/ql/src/semmle/code/csharp/Member.qll

@@ -1,11 +1,12 @@
 /** Provides classes relating to declarations and type members. */
 
-import Element
-import Variable
 import Callable
+import Element
 import Modifier
-private import Implements
+import Variable
 private import dotnet
+private import Implements
+private import TypeRef
 
 /**
  * A declaration.

csharp/ql/src/semmle/code/csharp/Property.qll

@@ -2,12 +2,13 @@
  * Provides classes for properties, indexers, and accessors.
  */
 
-import Type
 import Member
 import Stmt
-private import semmle.code.csharp.ExprOrStmtParent
-private import dotnet
+import Type
 private import cil
+private import dotnet
+private import semmle.code.csharp.ExprOrStmtParent
+private import TypeRef
 
 /**
  * A declaration that may have accessors. Either an event (`Event`), a property

csharp/ql/src/semmle/code/csharp/Stmt.qll

@@ -4,12 +4,13 @@
  * All statements have the common base class `Stmt`.
  */
 
-import Location
 import Element
+import Location
 import Member
 import exprs.Expr
 private import semmle.code.csharp.Enclosing::Internal
 private import semmle.code.csharp.frameworks.System
+private import TypeRef
 
 /**
  * A statement.

csharp/ql/src/semmle/code/csharp/Type.qll

@@ -1,14 +1,15 @@
 /** Provides classes for types. */
 
-import Location
-import Namespace
 import Callable
-import Property
 import Event
 import Generics
+import Location
+import Namespace
+import Property
 private import Conversion
-private import semmle.code.csharp.metrics.Coupling
 private import dotnet
+private import semmle.code.csharp.metrics.Coupling
+private import TypeRef
 
 /**
  * A type.
@@ -1002,73 +1003,3 @@ class TypeMention extends @type_mention {
   /** Gets the location of this type mention. */
   Location getLocation() { type_mention_location(this, result) }
 }
-
-/**
- * INTERNAL: Do not use.
- * Gets a type reference for a given type `type`.
- * This is used for extensionals that can be supplied
- * as either type references or types.
- */
-@type_or_ref getTypeRef(@type type) {
-  result = type
-  or
-  type = result.(TypeRefs::TypeRef).getCanonicalType()
-}
-
-/**
- * Module for reasoning about typerefs.
- */
-private module TypeRefs {
-  /**
-   * A typeref is a reference to a type in some assembly.
-   * Often, a type can be present in multiple assemblies.
-   */
-  class TypeRef extends @typeref {
-    string getName() { typerefs(this, result) }
-
-    string toString() { result = getName() }
-
-    Type getAType() { typeref_type(this, result) }
-
-    /**
-     * Gets the "canonical type" represented by a typeref.
-     * This is because a typeref can reference multiple types, or a type with the same
-     * fully qualified name can exist in multiple assemblies.
-     * The canonical type is an arbitrarily chosen type from the list of candidate types.
-     */
-    Type getCanonicalType() {
-      result = this.getAType() and
-      isCanonicalType(result)
-    }
-  }
-
-  /** Gets the location of a type. */
-  private Location typeLocation(Type t) {
-    type_location(t, result)
-    or
-    exists(Type decl | constructed_generic(decl, t) and result = typeLocation(decl))
-  }
-
-  /** Gets a "canonical location" for a type. A type has only one canonical location. */
-  private Location canonicalTypeLocation(Type t) {
-    result = typeLocation(t) and
-    not locationIsBetter(result, typeLocation(t))
-  }
-
-  pragma[inline]
-  private predicate locationIsBetter(Location typeLocation, Location betterLocation) {
-    typeLocation.(Assembly).getFullName() < betterLocation.(Assembly).getFullName()
-    or
-    typeLocation instanceof Assembly and betterLocation instanceof SourceLocation
-    or
-    typeLocation.(SourceLocation).getFile().getAbsolutePath() <
-      betterLocation.(SourceLocation).getFile().getAbsolutePath()
-  }
-
-  private predicate isCanonicalType(Type type) {
-    not exists(TypeRef tr |
-      type = tr.getAType() and
-      locationIsBetter(canonicalTypeLocation(type), canonicalTypeLocation(tr.getAType()))
-    )
-  }
-}

csharp/ql/src/semmle/code/csharp/TypeRef.qll

@@ -0,0 +1,73 @@
+/**
+ * INTERNAL: Do not use.
+ * Provides support for type-references.
+ */
+
+import csharp
+
+/**
+ * INTERNAL: Do not use.
+ * Gets a type reference for a given type `type`.
+ * This is used for extensionals that can be supplied
+ * as either type references or types.
+ */
+@type_or_ref getTypeRef(@type type) {
+  result = type
+  or
+  type = result.(TypeRefs::TypeRef).getCanonicalType()
+}
+
+private module TypeRefs {
+  /**
+   * A typeref is a reference to a type in some assembly.
+   * Often, a type can be present in multiple assemblies.
+   */
+  class TypeRef extends @typeref {
+    string getName() { typerefs(this, result) }
+
+    string toString() { result = getName() }
+
+    Type getAType() { typeref_type(this, result) }
+
+    /**
+     * Gets the "canonical type" represented by a typeref.
+     * This is because a typeref can reference multiple types, or a type with the same
+     * fully qualified name can exist in multiple assemblies.
+     * The canonical type is an arbitrarily chosen type from the list of candidate types.
+     */
+    Type getCanonicalType() {
+      result = this.getAType() and
+      isCanonicalType(result)
+    }
+  }
+
+  /** Gets a location of a type. */
+  private Location typeLocation(Type t) {
+    type_location(t, result)
+    or
+    exists(Type decl | constructed_generic(decl, t) and result = typeLocation(decl))
+  }
+
+  /** Gets the "canonical location" for a type. A type has only one canonical location. */
+  private Location canonicalTypeLocation(Type t) {
+    result = typeLocation(t) and
+    not locationIsBetter(result, typeLocation(t))
+  }
+
+  pragma[inline]
+  private predicate locationIsBetter(Location typeLocation, Location betterLocation) {
+    typeLocation.(Assembly).getFullName() < betterLocation.(Assembly).getFullName()
+    or
+    typeLocation instanceof Assembly and betterLocation instanceof SourceLocation
+    or
+    typeLocation.(SourceLocation).getFile().getAbsolutePath() <
+      betterLocation.(SourceLocation).getFile().getAbsolutePath()
+  }
+
+  private predicate isCanonicalType(Type type) {
+    not exists(TypeRef tr |
+      type = tr.getAType() and
+      locationIsBetter(canonicalTypeLocation(type), canonicalTypeLocation(tr.getAType()))
+    )
+  }
+}

csharp/ql/src/semmle/code/csharp/Using.qll

@@ -5,6 +5,7 @@
  */
 
 import Element
+private import TypeRef
 
 /**
  * A `using` directive. Either a namespace `using` directive

csharp/ql/src/semmle/code/csharp/Variable.qll

@@ -3,12 +3,13 @@
  * constants.
  */
 
-import Element
-import Callable
-import Type
 import Assignable
+import Callable
+import Element
+import Type
 private import dotnet
 private import semmle.code.csharp.ExprOrStmtParent
+private import TypeRef
 
 /**
  * A variable. Either a variable with local scope (`LocalScopeVariable`) or a field (`Field`).

csharp/ql/src/semmle/code/csharp/exprs/Expr.qll

@@ -4,10 +4,6 @@
  * All expressions have the common base class `Expr`.
  */
 
-import semmle.code.csharp.Location
-import semmle.code.csharp.Stmt
-import semmle.code.csharp.Callable
-import semmle.code.csharp.Type
 import Access
 import ArithmeticOperation
 import Assignment
@@ -19,9 +15,14 @@ import Dynamic
 import Literal
 import LogicalOperation
 import semmle.code.csharp.controlflow.ControlFlowElement
+import semmle.code.csharp.Callable
+import semmle.code.csharp.Location
+import semmle.code.csharp.Stmt
+import semmle.code.csharp.Type
+private import dotnet
 private import semmle.code.csharp.Enclosing::Internal
 private import semmle.code.csharp.frameworks.System
-private import dotnet
+private import semmle.code.csharp.TypeRef
 
 /**
  * An expression. Either an access (`Access`), a call (`Call`), an object or