Kotlin: Towards KotlinType support

java/ql/lib/config/semmlecode.dbscheme

@@ -314,6 +314,18 @@ classes(
   int sourceid: @class ref
 );
 
+kt_nullable_types(
+  unique int id: @kt_nullable_type,
+  int classid: @classorinterface ref
+)
+
+kt_notnull_types(
+  unique int id: @kt_notnull_type,
+  int classid: @classorinterface ref
+)
+
+@kt_type = @kt_nullable_type | @kt_notnull_type
+
 isRecord(
   unique int id: @class ref
 );
@@ -906,7 +918,7 @@ javadocText(
 @type = @primitive | @reftype;
 @callable = @method | @constructor;
 @element = @file | @package | @primitive | @class | @interface | @method | @constructor | @modifier | @param | @exception | @field |
-           @annotation | @boundedtype | @array | @localvar | @expr | @stmt | @import | @fielddecl;
+           @annotation | @boundedtype | @array | @localvar | @expr | @stmt | @import | @fielddecl | @kt_type;
 
 @modifiable = @member_modifiable| @param | @localvar ;
 

java/ql/lib/java.qll

@@ -20,6 +20,7 @@ import semmle.code.java.Javadoc
 import semmle.code.java.JDK
 import semmle.code.java.JDKAnnotations
 import semmle.code.java.JMX
+import semmle.code.java.KotlinType
 import semmle.code.java.Member
 import semmle.code.java.Modifier
 import semmle.code.java.Modules

java/ql/lib/semmle/code/java/KotlinType.qll

@@ -0,0 +1,27 @@
+/**
+ * Provides classes and predicates for working with Kotlin types.
+ */
+
+import java
+
+class KotlinType extends Element, @kt_type {
+}
+
+class KotlinNullableType extends KotlinType, @kt_nullable_type {
+  override string toString() {
+    exists(ClassOrInterface ci |
+           kt_nullable_types(this, ci) and
+           result = "Kotlin nullable " + ci.toString())
+  }
+  override string getAPrimaryQlClass() { result = "KotlinNullableType" }
+}
+
+class KotlinNotnullType extends KotlinType, @kt_notnull_type {
+  override string toString() {
+    exists(ClassOrInterface ci |
+           kt_notnull_types(this, ci) and
+           result = "Kotlin not-null " + ci.toString())
+  }
+  override string getAPrimaryQlClass() { result = "KotlinNotnullType" }
+}
+