Extract not-null expression

java/ql/lib/config/semmlecode.dbscheme

@@ -695,6 +695,7 @@ case @expr.kind of
 | 79  = @stmtexpr
 | 80  = @stringtemplateexpr
 | 81  = @varargexpr
+| 82  = @notnullexpr
 ;
 
 /** Holds if this `when` expression was written as an `if` expression. */
@@ -771,7 +772,8 @@ when_branch_else(unique int id: @whenbranch ref);
              | @minusexpr
              | @plusexpr
              | @bitnotexpr
-             | @lognotexpr;
+             | @lognotexpr
+             | @notnullexpr;
 
 @caller =  @classinstancexpr
          | @methodaccess

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

@@ -1463,9 +1463,7 @@ class InstanceOfExpr extends Expr, @instanceofexpr {
 /** An `instanceof` expression. */
 class NotInstanceOfExpr extends Expr, @notinstanceofexpr {
   /** Gets the expression on the left-hand side of the `!is` operator. */
-  Expr getExpr() {
-    result.isNthChildOf(this, 0)
-  }
+  Expr getExpr() { result.isNthChildOf(this, 0) }
 
   /** Gets the access to the type on the right-hand side of the `!is` operator. */
   Expr getTypeName() { result.isNthChildOf(this, 1) }
@@ -2195,19 +2193,13 @@ class WhenBranch extends Top, @whenbranch {
   Expr getCondition() { result.isNthChildOf(this, 0) }
 
   /** Gets the result of this branch. */
-  Stmt getRhs() {
-    result.isNthChildOf(this, 1)
-  }
+  Stmt getRhs() { result.isNthChildOf(this, 1) }
 
   /** Gets a result expression of this `when` branch. */
-  Expr getAResult() {
-    result = getAResult(this.getRhs())
-  }
+  Expr getAResult() { result = getAResult(this.getRhs()) }
 
   /** Holds if this is an `else` branch. */
-  predicate isElseBranch() {
-    when_branch_else(this)
-  }
+  predicate isElseBranch() { when_branch_else(this) }
 
   override string toString() { result = "... -> ..." }
 
@@ -2290,3 +2282,10 @@ class VarArgExpr extends Expr, @varargexpr {
 
   override string getAPrimaryQlClass() { result = "VarArgExpr" }
 }
+
+/** A Kotlin not-null expression. For example, `expr!!`. */
+class NotNullExpr extends UnaryExpr, @notnullexpr {
+  override string toString() { result = "...!!" }
+
+  override string getAPrimaryQlClass() { result = "NotNullExpr" }
+}

java/ql/test/kotlin/library-tests/exprs/exprs.expected

@@ -534,6 +534,9 @@
 | exprs.kt:193:31:193:37 | ... + ... | exprs.kt:192:16:194:9 | <obinit> | AddExpr |
 | exprs.kt:193:36:193:37 | a2 | exprs.kt:192:16:194:9 | <obinit> | VarAccess |
 | exprs.kt:193:40:193:49 | toString(...) | exprs.kt:192:16:194:9 | <obinit> | MethodAccess |
+| exprs.kt:199:5:199:20 | y | exprs.kt:198:1:200:1 | notNullAssertion | LocalVariableDeclExpr |
+| exprs.kt:199:18:199:18 | x | exprs.kt:198:1:200:1 | notNullAssertion | VarAccess |
+| exprs.kt:199:19:199:20 | ...!! | exprs.kt:198:1:200:1 | notNullAssertion | NotNullExpr |
 | file://:0:0:0:0 | C | exprs.kt:146:5:146:33 | foo | TypeAccess |
 | file://:0:0:0:0 | Color | exprs.kt:175:6:179:1 | Color | TypeAccess |
 | file://:0:0:0:0 | Direction | exprs.kt:171:6:173:1 | Direction | TypeAccess |

java/ql/test/kotlin/library-tests/exprs/exprs.kt

@@ -194,3 +194,7 @@ class Class1 {
         }
     }
 }
+
+fun notNullAssertion(x: Any?) {
+    val y: Any = x!!
+}

java/ql/test/kotlin/library-tests/exprs/unaryOp.expected

@@ -0,0 +1 @@
+| exprs.kt:199:19:199:20 | ...!! | exprs.kt:199:18:199:18 | x |

java/ql/test/kotlin/library-tests/exprs/unaryOp.ql

@@ -0,0 +1,36 @@
+import java
+
+newtype TMaybeElement =
+  TElement(Element e) or
+  TNoElement()
+
+class MaybeElement extends TMaybeElement {
+  abstract string toString();
+
+  abstract Location getLocation();
+}
+
+class YesMaybeElement extends MaybeElement {
+  Element e;
+
+  YesMaybeElement() { this = TElement(e) }
+
+  override string toString() { result = e.toString() }
+
+  override Location getLocation() { result = e.getLocation() }
+}
+
+class NoMaybeElement extends MaybeElement {
+  NoMaybeElement() { this = TNoElement() }
+
+  override string toString() { result = "<none>" }
+
+  override Location getLocation() { none() }
+}
+
+MaybeElement op(UnaryExpr e) {
+  if exists(e.getExpr()) then result = TElement(e.getExpr()) else result = TNoElement()
+}
+
+from Expr e
+select e, op(e)