C#: Simplify TypeRef.qll

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

@@ -1,67 +1,29 @@
 /**
  * INTERNAL: Do not use.
+ *
  * Provides support for type-references.
  */
 
 import csharp
 
+/** A typeref is a reference to a type in some assembly. */
+private class TypeRef extends @typeref {
+  string getName() { typerefs(this, result) }
+
+  string toString() { result = this.getName() }
+
+  Type getReferencedType() { typeref_type(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.
  */
-cached
-@type_or_ref getTypeRef(@type type) {
+@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
-      not locationIsBetter(canonicalTypeLocation(result), canonicalTypeLocation(this.getAType()))
-    }
-  }
-
-  /** 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()
-  }
+  result.(TypeRef).getReferencedType() = type
 }