add support for the new assign expression in TypeScript 4

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

@@ -77,6 +77,9 @@ public class ExprKinds {
     binOpKinds.put("**", 87);
     binOpKinds.put("**=", 88);
     binOpKinds.put("??", 107);
+    binOpKinds.put("&&=", 116);
+    binOpKinds.put("||=", 117);
+    binOpKinds.put("??=", 118);
   }
 
   private static final Map<String, Integer> unOpKinds = new LinkedHashMap<String, Integer>();

javascript/ql/src/semmle/javascript/Expr.qll

@@ -1851,7 +1851,7 @@ class AssignExpr extends @assignexpr, Assignment {
 private class TCompoundAssignExpr =
   @assignaddexpr or @assignsubexpr or @assignmulexpr or @assigndivexpr or @assignmodexpr or
       @assignexpexpr or @assignlshiftexpr or @assignrshiftexpr or @assignurshiftexpr or
-      @assignorexpr or @assignxorexpr or @assignandexpr;
+      @assignorexpr or @assignxorexpr or @assignandexpr or @assignlogandexpr or @assignlogorexpr or @assignnullishcoalescingexpr;
 
 /**
  * A compound assign expression.
@@ -1997,6 +1997,39 @@ class AssignXOrExpr extends @assignxorexpr, CompoundAssignExpr { }
  */
 class AssignAndExpr extends @assignandexpr, CompoundAssignExpr { }
 
+/**
+ * A logical-'or'-assign expression.
+ *
+ * Example:
+ *
+ * ```
+ * x ||= y
+ * ```
+ */
+class AssignLogOrExpr extends @assignlogandexpr, CompoundAssignExpr { }
+
+/**
+ * A logical-'and'-assign expression.
+ *
+ * Example:
+ *
+ * ```
+ * x &&= y
+ * ```
+ */
+class AssignLogAndExpr extends @assignlogorexpr, CompoundAssignExpr { }
+
+/**
+ * A 'nullish-coalescing'-assign expression.
+ *
+ * Example:
+ *
+ * ```
+ * x ??= y
+ * ```
+ */
+class AssignNullishCoalescingExpr extends @assignnullishcoalescingexpr, CompoundAssignExpr { }
+
 /**
  * An update expression, that is, an increment or decrement expression.
  *

javascript/ql/src/semmlecode.javascript.dbscheme

@@ -351,6 +351,9 @@ case @expr.kind of
 | 113 = @e4x_xml_dynamic_qualident
 | 114 = @e4x_xml_dotdotexpr
 | 115 = @importmetaexpr
+| 116 = @assignlogandexpr
+| 117 = @assignlogorexpr
+| 118 = @assignnullishcoalescingexpr
 ;
 
 @varaccess = @proper_varaccess | @export_varaccess;
@@ -372,7 +375,7 @@ case @expr.kind of
 
 @binaryexpr = @comparison | @lshiftexpr | @rshiftexpr | @urshiftexpr | @addexpr | @subexpr | @mulexpr | @divexpr | @modexpr | @expexpr | @bitorexpr | @xorexpr | @bitandexpr | @inexpr | @instanceofexpr | @logandexpr | @logorexpr | @nullishcoalescingexpr;
 
-@assignment = @assignexpr | @assignaddexpr | @assignsubexpr | @assignmulexpr | @assigndivexpr | @assignmodexpr | @assignexpexpr | @assignlshiftexpr | @assignrshiftexpr | @assignurshiftexpr | @assignorexpr | @assignxorexpr | @assignandexpr;
+@assignment = @assignexpr | @assignaddexpr | @assignsubexpr | @assignmulexpr | @assigndivexpr | @assignmodexpr | @assignexpexpr | @assignlshiftexpr | @assignrshiftexpr | @assignurshiftexpr | @assignorexpr | @assignxorexpr | @assignandexpr | @assignlogandexpr | @assignlogorexpr | @assignnullishcoalescingexpr;
 
 @updateexpr = @preincexpr | @postincexpr | @predecexpr | @postdecexpr;
 

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

@@ -113,6 +113,9 @@ test_VariableTypes
 | tst.ts:164:56:164:59 | arr2 | arr2 | tst.ts:164:62:164:62 | U |
 | tst.ts:169:31:169:31 | x | x | tst.ts:169:34:169:64 | [first: ... number] |
 | tst.ts:180:5:180:7 | foo | foo | tst.ts:180:10:180:21 | StrStrNumNum |
+| tst.ts:184:7:184:8 | a1 | a1 | tst.ts:184:12:184:17 | number |
+| tst.ts:185:7:185:8 | a2 | a2 | tst.ts:185:12:185:17 | number |
+| tst.ts:186:7:186:8 | a3 | a3 | tst.ts:186:12:186:17 | number |
 test_QualifiedTypeAccess
 | tst.ts:63:19:63:21 | N.I | tst.ts:63:19:63:19 | N | tst.ts:63:21:63:21 | I |
 | tst.ts:64:20:64:24 | N.M.I | tst.ts:64:20:64:22 | N.M | tst.ts:64:24:64:24 | I |

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

@@ -177,4 +177,13 @@ type Numbers = [number, number];
 
 // [string, string, number, number]
 type StrStrNumNum = [...Strings, ...Numbers];
-var foo: StrStrNumNum;
+var foo: StrStrNumNum;
+
+// Short-Circuiting Assignment Operators
+function shortAssignment() {
+  let a1 : number = parseInt("foo");
+  let a2 : number = parseInt("bar");
+  let a3 : number = a1 ||= a2;
+  let a4 = a2 &&= a3;
+  let a5 = a3 ??= a4;
+}