TS: Support readonly type expressions

Author: asger-semmle

javascript/extractor/src/com/semmle/js/extractor/TypeExprKinds.java

@@ -66,6 +66,7 @@ public class TypeExprKinds {
   private static final int optionalTypeExpr = 33;
   private static final int restTypeExpr = 34;
   private static final int bigintLiteralTypeExpr = 35;
+  private static final int readonlyTypeExpr = 36;
 
   public static int getTypeExprKind(final INode type, final IdContext idcontext) {
     Integer kind =
@@ -127,7 +128,11 @@ public Integer visit(TupleTypeExpr nd, Void c) {
 
               @Override
               public Integer visit(UnaryTypeExpr nd, Void c) {
-                return keyofTypeExpr;
+                switch (nd.getKind()) {
+                  case Keyof: return keyofTypeExpr;
+                  case Readonly: return readonlyTypeExpr;
+                }
+                throw new CatastrophicError("Unhandled UnaryTypeExpr kind: " + nd.getKind());
               }
 
               @Override

javascript/extractor/src/com/semmle/js/parser/TypeScriptASTConverter.java

@@ -2132,6 +2132,9 @@ private Node convertTypeOperator(JsonObject node, SourceLocation loc) throws Par
     if (operator.equals("KeyOfKeyword")) {
       return new UnaryTypeExpr(loc, UnaryTypeExpr.Kind.Keyof, convertChildAsType(node, "type"));
     }
+    if (operator.equals("ReadonlyKeyword")) {
+      return new UnaryTypeExpr(loc, UnaryTypeExpr.Kind.Readonly, convertChildAsType(node, "type"));
+    }
     if (operator.equals("UniqueKeyword")) {
       return new KeywordTypeExpr(loc, "unique symbol");
     }

javascript/ql/src/semmle/javascript/TypeScript.qll

@@ -970,6 +970,14 @@ class RestTypeExpr extends @resttypeexpr, TypeExpr {
   TypeExpr getElementType() { result = getArrayType().(ArrayTypeExpr).getElementType() }
 }
 
+/**
+ * A type of form `readonly T`, such as `readonly number[]`.
+ */
+class ReadonlyTypeExpr extends @readonlytypeexpr, TypeExpr {
+  /** Gets the type `T` in `readonly T`. */
+  TypeExpr getElementType() { result = getChildTypeExpr(0) }
+}
+
 /**
  * A possibly qualified name that refers to a variable from inside a type.
  *

javascript/ql/src/semmlecode.javascript.dbscheme

@@ -573,6 +573,7 @@ case @typeexpr.kind of
 | 33 = @optionaltypeexpr
 | 34 = @resttypeexpr
 | 35 = @bigintliteraltypeexpr
+| 36 = @readonlytypeexpr
 ;
 
 @typeref = @typeaccess | @typedecl;

javascript/ql/test/library-tests/TypeScript/ArrayTypes/ArrayTypes.expected

@@ -1,16 +1,20 @@
 | (T \| ConcatArray<T>)[] | `T \| ConcatArray<T>` |
 | (number \| ConcatArray<number>)[] | `number \| ConcatArray<number>` |
+| (number[] \| ConcatArray<number[]>)[] | `number[] \| ConcatArray<number[]>` |
 | (string \| number \| ConcatArray<string \| number>)[] | `string \| number \| ConcatArray<string \| number>` |
 | (string \| number)[] | `string \| number` |
 | ConcatArray<T>[] | `ConcatArray<T>` |
 | ConcatArray<number>[] | `ConcatArray<number>` |
+| ConcatArray<number[]>[] | `ConcatArray<number[]>` |
 | ConcatArray<string \| number>[] | `ConcatArray<string \| number>` |
 | S[] | `S` |
 | T[] | `T` |
 | U[] | `U` |
 | [number, string] | `string \| number` |
 | any[] | `any` |
 | number[] | `number` |
+| number[][] | `number[]` |
 | readonly T[] | `T` |
 | readonly number[] | `number` |
+| readonly number[][] | `number[]` |
 | string[] | `string` |

javascript/ql/test/library-tests/TypeScript/ArrayTypes/NumberIndexTypes.expected

@@ -1,9 +1,11 @@
 | (T \| ConcatArray<T>)[] | T \| ConcatArray<T> |
 | (number \| ConcatArray<number>)[] | number \| ConcatArray<number> |
+| (number[] \| ConcatArray<number[]>)[] | number[] \| ConcatArray<number[]> |
 | (string \| number \| ConcatArray<string \| number>)[] | string \| number \| ConcatArray<string \| number> |
 | (string \| number)[] | string \| number |
 | ConcatArray<T>[] | ConcatArray<T> |
 | ConcatArray<number>[] | ConcatArray<number> |
+| ConcatArray<number[]>[] | ConcatArray<number[]> |
 | ConcatArray<string \| number>[] | ConcatArray<string \| number> |
 | NumberIndexable | object |
 | S[] | S |
@@ -12,7 +14,9 @@
 | [number, string] | string \| number |
 | any[] | any |
 | number[] | number |
+| number[][] | number[] |
 | readonly T[] | T |
 | readonly number[] | number |
+| readonly number[][] | number[] |
 | string | string |
 | string[] | string |

javascript/ql/test/library-tests/TypeScript/ArrayTypes/tst.ts

@@ -1,5 +1,5 @@
 let plain: number[];
-let radonly: ReadonlyArray<number>;
+let readonly: ReadonlyArray<number>;
 let tuple: [number, string];
 
 interface NumberIndexable {
@@ -14,3 +14,6 @@ interface StringIndexable {
 
 let numberIndexable: NumberIndexable;
 let stringIndexable: StringIndexable;
+
+let readonlySyntax: readonly number[];
+let readonlySyntax2: readonly number[][];