CFG changes for non-null operator + some tests

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

@@ -163,7 +163,8 @@ private module ControlFlowGraphImpl {
    * Bind `t` to an exception type that may be thrown during execution of `n`,
    * either because `n` is a `throw` statement, or because it is a call
    * that may throw an exception, or because it is a cast and a
-   * `ClassCastException` is expected.
+   * `ClassCastException` is expected, or because it is a Kotlin not-null check
+   * and a `NullPointerException` is expected.
    */
   private predicate mayThrow(ControlFlowNode n, ThrowableType t) {
     t = n.(ThrowStmt).getThrownExceptionType()
@@ -179,6 +180,11 @@ private module ControlFlowGraphImpl {
       t instanceof TypeClassCastException and
       uncheckedExceptionFromCatch(n, t)
     )
+    or
+    exists(NotNullExpr nn | nn = n |
+      t instanceof TypeNullPointerException and
+      uncheckedExceptionFromCatch(n, t)
+    )
   }
 
   /**
@@ -304,12 +310,12 @@ private module ControlFlowGraphImpl {
     or
     exists(ConditionalStmt condstmt | condstmt.getCondition() = b)
     or
-    exists(WhenBranch whenbranch |
-      whenbranch.getCondition() = b)
+    exists(WhenBranch whenbranch | whenbranch.getCondition() = b)
     or
     exists(WhenExpr whenexpr |
       inBooleanContext(whenexpr) and
-      whenexpr.getBranch(_).getAResult() = b)
+      whenexpr.getBranch(_).getAResult() = b
+    )
   }
 
   /**
@@ -419,7 +425,9 @@ private module ControlFlowGraphImpl {
     exists(WhenExpr whenexpr | whenexpr = result |
       whenexpr.getBranch(_).isElseBranch() and
       forex(WhenBranch whenbranch | whenbranch = whenexpr.getBranch(_) |
-        whenbranch.getRhs() = nonReturningStmt()))
+        whenbranch.getRhs() = nonReturningStmt()
+      )
+    )
   }
 
   /**
@@ -947,9 +955,10 @@ private module ControlFlowGraphImpl {
       or
       // If our last branch condition is false then we are done
       exists(int i |
-             last(whenexpr.getBranch(i), last, BooleanCompletion(false, _)) and
-             completion = NormalCompletion() and
-             not exists(whenexpr.getBranch(i + 1)))
+        last(whenexpr.getBranch(i), last, BooleanCompletion(false, _)) and
+        completion = NormalCompletion() and
+        not exists(whenexpr.getBranch(i + 1))
+      )
       or
       // Any branch getting an abnormal completion is propogated
       last(whenexpr.getBranch(_), last, completion) and
@@ -1249,13 +1258,15 @@ private module ControlFlowGraphImpl {
     or
     // When expressions:
     exists(WhenExpr whenexpr | n = whenexpr |
-      n = whenexpr and result = first(whenexpr.getBranch(0)) and
+      n = whenexpr and
+      result = first(whenexpr.getBranch(0)) and
       completion = NormalCompletion()
       or
       exists(int i |
         last(whenexpr.getBranch(i), n, completion) and
         completion = BooleanCompletion(false, _) and
-        result = first(whenexpr.getBranch(i + 1)))
+        result = first(whenexpr.getBranch(i + 1))
+      )
     )
     or
     // When branches:

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

@@ -104,6 +104,11 @@ class TypeClassCastException extends Class {
   TypeClassCastException() { this.hasQualifiedName("java.lang", "ClassCastException") }
 }
 
+/** The class `java.lang.NullPointerException`. */
+class TypeNullPointerException extends Class {
+  TypeNullPointerException() { this.hasQualifiedName("java.lang", "NullPointerException") }
+}
+
 /**
  * The class `java.lang.Class`.
  *

java/ql/test/kotlin/library-tests/controlflow/basic/Test.kt

@@ -78,3 +78,21 @@ TODO
 		return
 	}
 }
+
+fun t1(o: Any): Int {
+	try {
+		val x = o as Int
+		return 1
+	} catch (e: ClassCastException) {
+		return 2
+	}
+}
+
+fun t2(o: Any?): Int {
+	try {
+		val x = o!!
+		return 1
+	} catch (e: NullPointerException) {
+		return 2
+	}
+}

java/ql/test/kotlin/library-tests/controlflow/basic/bbStmts.expected

@@ -105,3 +105,23 @@
 | Test.kt:43:3:43:3 | <Expr>; | 9 | Test.kt:78:3:78:8 | INSTANCE |
 | Test.kt:43:3:43:3 | <Expr>; | 10 | Test.kt:78:3:78:8 | return ... |
 | Test.kt:43:3:43:3 | <Expr>; | 11 | Test.kt:4:2:79:2 | test |
+| Test.kt:82:1:89:1 | t1 | 0 | Test.kt:82:1:89:1 | t1 |
+| Test.kt:82:21:89:1 | { ... } | 0 | Test.kt:82:21:89:1 | { ... } |
+| Test.kt:82:21:89:1 | { ... } | 1 | Test.kt:83:2:88:2 | try ... |
+| Test.kt:82:21:89:1 | { ... } | 2 | Test.kt:83:6:86:2 | { ... } |
+| Test.kt:82:21:89:1 | { ... } | 3 | Test.kt:84:3:84:18 | var ...; |
+| Test.kt:82:21:89:1 | { ... } | 4 | Test.kt:84:11:84:11 | o |
+| Test.kt:82:21:89:1 | { ... } | 5 | Test.kt:84:11:84:18 | (...)... |
+| Test.kt:84:3:84:18 | x | 0 | Test.kt:84:3:84:18 | x |
+| Test.kt:84:3:84:18 | x | 1 | Test.kt:85:10:85:10 | 1 |
+| Test.kt:84:3:84:18 | x | 2 | Test.kt:85:3:85:10 | return ... |
+| Test.kt:91:1:98:1 | t2 | 0 | Test.kt:91:1:98:1 | t2 |
+| Test.kt:91:22:98:1 | { ... } | 0 | Test.kt:91:22:98:1 | { ... } |
+| Test.kt:91:22:98:1 | { ... } | 1 | Test.kt:92:2:97:2 | try ... |
+| Test.kt:91:22:98:1 | { ... } | 2 | Test.kt:92:6:95:2 | { ... } |
+| Test.kt:91:22:98:1 | { ... } | 3 | Test.kt:93:3:93:13 | var ...; |
+| Test.kt:91:22:98:1 | { ... } | 4 | Test.kt:93:11:93:11 | o |
+| Test.kt:91:22:98:1 | { ... } | 5 | Test.kt:93:12:93:13 | ...!! |
+| Test.kt:93:3:93:13 | x | 0 | Test.kt:93:3:93:13 | x |
+| Test.kt:93:3:93:13 | x | 1 | Test.kt:94:10:94:10 | 1 |
+| Test.kt:93:3:93:13 | x | 2 | Test.kt:94:3:94:10 | return ... |

java/ql/test/kotlin/library-tests/controlflow/basic/bbStrictDominance.expected

@@ -14,3 +14,9 @@
 | Test.kt:35:3:35:3 | <Expr>; | Test.kt:43:3:43:3 | <Expr>; |
 | Test.kt:38:9:38:9 | x | Test.kt:38:16:41:3 | { ... } |
 | Test.kt:38:9:38:9 | x | Test.kt:43:3:43:3 | <Expr>; |
+| Test.kt:82:21:89:1 | { ... } | Test.kt:82:1:89:1 | t1 |
+| Test.kt:82:21:89:1 | { ... } | Test.kt:84:3:84:18 | x |
+| Test.kt:82:21:89:1 | { ... } | file://:0:0:0:0 | catch (...) |
+| Test.kt:91:22:98:1 | { ... } | Test.kt:91:1:98:1 | t2 |
+| Test.kt:91:22:98:1 | { ... } | Test.kt:93:3:93:13 | x |
+| Test.kt:91:22:98:1 | { ... } | file://:0:0:0:0 | catch (...) |

java/ql/test/kotlin/library-tests/controlflow/basic/bbSuccessor.expected

@@ -7,3 +7,11 @@
 | Test.kt:38:9:38:9 | x | Test.kt:38:16:41:3 | { ... } |
 | Test.kt:38:9:38:9 | x | Test.kt:43:3:43:3 | <Expr>; |
 | Test.kt:38:16:41:3 | { ... } | Test.kt:38:9:38:9 | x |
+| Test.kt:82:21:89:1 | { ... } | Test.kt:84:3:84:18 | x |
+| Test.kt:82:21:89:1 | { ... } | file://:0:0:0:0 | catch (...) |
+| Test.kt:84:3:84:18 | x | Test.kt:82:1:89:1 | t1 |
+| Test.kt:91:22:98:1 | { ... } | Test.kt:93:3:93:13 | x |
+| Test.kt:91:22:98:1 | { ... } | file://:0:0:0:0 | catch (...) |
+| Test.kt:93:3:93:13 | x | Test.kt:91:1:98:1 | t2 |
+| file://:0:0:0:0 | catch (...) | Test.kt:82:1:89:1 | t1 |
+| file://:0:0:0:0 | catch (...) | Test.kt:91:1:98:1 | t2 |

java/ql/test/kotlin/library-tests/controlflow/basic/getASuccessor.expected

@@ -130,3 +130,42 @@
 | Test.kt:77:7:77:8 | 40 | IntegerLiteral | Test.kt:77:3:77:3 | ...=... | AssignExpr |
 | Test.kt:78:3:78:8 | INSTANCE | VarAccess | Test.kt:78:3:78:8 | return ... | ReturnStmt |
 | Test.kt:78:3:78:8 | return ... | ReturnStmt | Test.kt:4:2:79:2 | test | Method |
+| Test.kt:82:1:89:1 | t1 | Method | file://:0:0:0:0 | <none> | <none> |
+| Test.kt:82:8:82:13 | o | Parameter | file://:0:0:0:0 | <none> | <none> |
+| Test.kt:82:21:89:1 | { ... } | BlockStmt | Test.kt:83:2:88:2 | try ... | TryStmt |
+| Test.kt:83:2:88:2 | try ... | TryStmt | Test.kt:83:6:86:2 | { ... } | BlockStmt |
+| Test.kt:83:6:86:2 | { ... } | BlockStmt | Test.kt:84:3:84:18 | var ...; | LocalVariableDeclStmt |
+| Test.kt:84:3:84:18 | int x | LocalVariableDecl | file://:0:0:0:0 | <none> | <none> |
+| Test.kt:84:3:84:18 | var ...; | LocalVariableDeclStmt | Test.kt:84:11:84:11 | o | VarAccess |
+| Test.kt:84:3:84:18 | x | LocalVariableDeclExpr | Test.kt:85:10:85:10 | 1 | IntegerLiteral |
+| Test.kt:84:11:84:11 | o | VarAccess | Test.kt:84:11:84:18 | (...)... | CastExpr |
+| Test.kt:84:11:84:18 | (...)... | CastExpr | Test.kt:84:3:84:18 | x | LocalVariableDeclExpr |
+| Test.kt:84:11:84:18 | (...)... | CastExpr | file://:0:0:0:0 | catch (...) | CatchClause |
+| Test.kt:84:11:84:18 | int | TypeAccess | file://:0:0:0:0 | <none> | <none> |
+| Test.kt:85:3:85:10 | return ... | ReturnStmt | Test.kt:82:1:89:1 | t1 | Method |
+| Test.kt:85:10:85:10 | 1 | IntegerLiteral | Test.kt:85:3:85:10 | return ... | ReturnStmt |
+| Test.kt:86:11:86:31 | ClassCastException | TypeAccess | file://:0:0:0:0 | <none> | <none> |
+| Test.kt:86:11:86:31 | ClassCastException e | LocalVariableDecl | file://:0:0:0:0 | <none> | <none> |
+| Test.kt:86:11:86:31 | e | LocalVariableDeclExpr | Test.kt:86:34:88:2 | { ... } | BlockStmt |
+| Test.kt:86:34:88:2 | { ... } | BlockStmt | Test.kt:87:10:87:10 | 2 | IntegerLiteral |
+| Test.kt:87:3:87:10 | return ... | ReturnStmt | Test.kt:82:1:89:1 | t1 | Method |
+| Test.kt:87:10:87:10 | 2 | IntegerLiteral | Test.kt:87:3:87:10 | return ... | ReturnStmt |
+| Test.kt:91:1:98:1 | t2 | Method | file://:0:0:0:0 | <none> | <none> |
+| Test.kt:91:8:91:14 | o | Parameter | file://:0:0:0:0 | <none> | <none> |
+| Test.kt:91:22:98:1 | { ... } | BlockStmt | Test.kt:92:2:97:2 | try ... | TryStmt |
+| Test.kt:92:2:97:2 | try ... | TryStmt | Test.kt:92:6:95:2 | { ... } | BlockStmt |
+| Test.kt:92:6:95:2 | { ... } | BlockStmt | Test.kt:93:3:93:13 | var ...; | LocalVariableDeclStmt |
+| Test.kt:93:3:93:13 | Object x | LocalVariableDecl | file://:0:0:0:0 | <none> | <none> |
+| Test.kt:93:3:93:13 | var ...; | LocalVariableDeclStmt | Test.kt:93:11:93:11 | o | VarAccess |
+| Test.kt:93:3:93:13 | x | LocalVariableDeclExpr | Test.kt:94:10:94:10 | 1 | IntegerLiteral |
+| Test.kt:93:11:93:11 | o | VarAccess | Test.kt:93:12:93:13 | ...!! | NotNullExpr |
+| Test.kt:93:12:93:13 | ...!! | NotNullExpr | Test.kt:93:3:93:13 | x | LocalVariableDeclExpr |
+| Test.kt:93:12:93:13 | ...!! | NotNullExpr | file://:0:0:0:0 | catch (...) | CatchClause |
+| Test.kt:94:3:94:10 | return ... | ReturnStmt | Test.kt:91:1:98:1 | t2 | Method |
+| Test.kt:94:10:94:10 | 1 | IntegerLiteral | Test.kt:94:3:94:10 | return ... | ReturnStmt |
+| Test.kt:95:11:95:33 | NullPointerException | TypeAccess | file://:0:0:0:0 | <none> | <none> |
+| Test.kt:95:11:95:33 | NullPointerException e | LocalVariableDecl | file://:0:0:0:0 | <none> | <none> |
+| Test.kt:95:11:95:33 | e | LocalVariableDeclExpr | Test.kt:95:36:97:2 | { ... } | BlockStmt |
+| Test.kt:95:36:97:2 | { ... } | BlockStmt | Test.kt:96:10:96:10 | 2 | IntegerLiteral |
+| Test.kt:96:3:96:10 | return ... | ReturnStmt | Test.kt:91:1:98:1 | t2 | Method |
+| Test.kt:96:10:96:10 | 2 | IntegerLiteral | Test.kt:96:3:96:10 | return ... | ReturnStmt |

java/ql/test/kotlin/library-tests/controlflow/basic/strictDominance.expected

@@ -368,5 +368,55 @@
 | Test.kt:73:3:73:3 | <Expr>; | Test.kt:77:3:77:3 | <Expr>; |
 | Test.kt:73:3:73:3 | <Expr>; | Test.kt:78:3:78:8 | return ... |
 | Test.kt:77:3:77:3 | <Expr>; | Test.kt:78:3:78:8 | return ... |
+| Test.kt:82:21:89:1 | { ... } | Test.kt:83:2:88:2 | try ... |
+| Test.kt:82:21:89:1 | { ... } | Test.kt:83:6:86:2 | { ... } |
+| Test.kt:82:21:89:1 | { ... } | Test.kt:84:3:84:18 | var ...; |
+| Test.kt:82:21:89:1 | { ... } | Test.kt:85:3:85:10 | return ... |
+| Test.kt:82:21:89:1 | { ... } | Test.kt:86:34:88:2 | { ... } |
+| Test.kt:82:21:89:1 | { ... } | Test.kt:87:3:87:10 | return ... |
+| Test.kt:82:21:89:1 | { ... } | file://:0:0:0:0 | catch (...) |
+| Test.kt:83:2:88:2 | try ... | Test.kt:83:6:86:2 | { ... } |
+| Test.kt:83:2:88:2 | try ... | Test.kt:84:3:84:18 | var ...; |
+| Test.kt:83:2:88:2 | try ... | Test.kt:85:3:85:10 | return ... |
+| Test.kt:83:2:88:2 | try ... | Test.kt:86:34:88:2 | { ... } |
+| Test.kt:83:2:88:2 | try ... | Test.kt:87:3:87:10 | return ... |
+| Test.kt:83:2:88:2 | try ... | file://:0:0:0:0 | catch (...) |
+| Test.kt:83:6:86:2 | { ... } | Test.kt:84:3:84:18 | var ...; |
+| Test.kt:83:6:86:2 | { ... } | Test.kt:85:3:85:10 | return ... |
+| Test.kt:83:6:86:2 | { ... } | Test.kt:86:34:88:2 | { ... } |
+| Test.kt:83:6:86:2 | { ... } | Test.kt:87:3:87:10 | return ... |
+| Test.kt:83:6:86:2 | { ... } | file://:0:0:0:0 | catch (...) |
+| Test.kt:84:3:84:18 | var ...; | Test.kt:85:3:85:10 | return ... |
+| Test.kt:84:3:84:18 | var ...; | Test.kt:86:34:88:2 | { ... } |
+| Test.kt:84:3:84:18 | var ...; | Test.kt:87:3:87:10 | return ... |
+| Test.kt:84:3:84:18 | var ...; | file://:0:0:0:0 | catch (...) |
+| Test.kt:86:34:88:2 | { ... } | Test.kt:87:3:87:10 | return ... |
+| Test.kt:91:22:98:1 | { ... } | Test.kt:92:2:97:2 | try ... |
+| Test.kt:91:22:98:1 | { ... } | Test.kt:92:6:95:2 | { ... } |
+| Test.kt:91:22:98:1 | { ... } | Test.kt:93:3:93:13 | var ...; |
+| Test.kt:91:22:98:1 | { ... } | Test.kt:94:3:94:10 | return ... |
+| Test.kt:91:22:98:1 | { ... } | Test.kt:95:36:97:2 | { ... } |
+| Test.kt:91:22:98:1 | { ... } | Test.kt:96:3:96:10 | return ... |
+| Test.kt:91:22:98:1 | { ... } | file://:0:0:0:0 | catch (...) |
+| Test.kt:92:2:97:2 | try ... | Test.kt:92:6:95:2 | { ... } |
+| Test.kt:92:2:97:2 | try ... | Test.kt:93:3:93:13 | var ...; |
+| Test.kt:92:2:97:2 | try ... | Test.kt:94:3:94:10 | return ... |
+| Test.kt:92:2:97:2 | try ... | Test.kt:95:36:97:2 | { ... } |
+| Test.kt:92:2:97:2 | try ... | Test.kt:96:3:96:10 | return ... |
+| Test.kt:92:2:97:2 | try ... | file://:0:0:0:0 | catch (...) |
+| Test.kt:92:6:95:2 | { ... } | Test.kt:93:3:93:13 | var ...; |
+| Test.kt:92:6:95:2 | { ... } | Test.kt:94:3:94:10 | return ... |
+| Test.kt:92:6:95:2 | { ... } | Test.kt:95:36:97:2 | { ... } |
+| Test.kt:92:6:95:2 | { ... } | Test.kt:96:3:96:10 | return ... |
+| Test.kt:92:6:95:2 | { ... } | file://:0:0:0:0 | catch (...) |
+| Test.kt:93:3:93:13 | var ...; | Test.kt:94:3:94:10 | return ... |
+| Test.kt:93:3:93:13 | var ...; | Test.kt:95:36:97:2 | { ... } |
+| Test.kt:93:3:93:13 | var ...; | Test.kt:96:3:96:10 | return ... |
+| Test.kt:93:3:93:13 | var ...; | file://:0:0:0:0 | catch (...) |
+| Test.kt:95:36:97:2 | { ... } | Test.kt:96:3:96:10 | return ... |
+| file://:0:0:0:0 | catch (...) | Test.kt:86:34:88:2 | { ... } |
+| file://:0:0:0:0 | catch (...) | Test.kt:87:3:87:10 | return ... |
+| file://:0:0:0:0 | catch (...) | Test.kt:95:36:97:2 | { ... } |
+| file://:0:0:0:0 | catch (...) | Test.kt:96:3:96:10 | return ... |
 | file://:0:0:0:0 | var ...; | Test.kt:40:4:40:4 | <Expr>; |
 | file://:0:0:0:0 | var ...; | Test.kt:40:4:40:6 | <Expr>; |

java/ql/test/kotlin/library-tests/controlflow/basic/strictPostDominance.expected

@@ -280,6 +280,24 @@
 | Test.kt:78:3:78:8 | return ... | Test.kt:73:3:73:3 | <Expr>; |
 | Test.kt:78:3:78:8 | return ... | Test.kt:77:3:77:3 | <Expr>; |
 | Test.kt:78:3:78:8 | return ... | file://:0:0:0:0 | var ...; |
+| Test.kt:83:2:88:2 | try ... | Test.kt:82:21:89:1 | { ... } |
+| Test.kt:83:6:86:2 | { ... } | Test.kt:82:21:89:1 | { ... } |
+| Test.kt:83:6:86:2 | { ... } | Test.kt:83:2:88:2 | try ... |
+| Test.kt:84:3:84:18 | var ...; | Test.kt:82:21:89:1 | { ... } |
+| Test.kt:84:3:84:18 | var ...; | Test.kt:83:2:88:2 | try ... |
+| Test.kt:84:3:84:18 | var ...; | Test.kt:83:6:86:2 | { ... } |
+| Test.kt:86:34:88:2 | { ... } | file://:0:0:0:0 | catch (...) |
+| Test.kt:87:3:87:10 | return ... | Test.kt:86:34:88:2 | { ... } |
+| Test.kt:87:3:87:10 | return ... | file://:0:0:0:0 | catch (...) |
+| Test.kt:92:2:97:2 | try ... | Test.kt:91:22:98:1 | { ... } |
+| Test.kt:92:6:95:2 | { ... } | Test.kt:91:22:98:1 | { ... } |
+| Test.kt:92:6:95:2 | { ... } | Test.kt:92:2:97:2 | try ... |
+| Test.kt:93:3:93:13 | var ...; | Test.kt:91:22:98:1 | { ... } |
+| Test.kt:93:3:93:13 | var ...; | Test.kt:92:2:97:2 | try ... |
+| Test.kt:93:3:93:13 | var ...; | Test.kt:92:6:95:2 | { ... } |
+| Test.kt:95:36:97:2 | { ... } | file://:0:0:0:0 | catch (...) |
+| Test.kt:96:3:96:10 | return ... | Test.kt:95:36:97:2 | { ... } |
+| Test.kt:96:3:96:10 | return ... | file://:0:0:0:0 | catch (...) |
 | file://:0:0:0:0 | var ...; | Test.kt:38:16:41:3 | { ... } |
 | file://:0:0:0:0 | var ...; | Test.kt:39:4:39:4 | <Expr>; |
 | file://:0:0:0:0 | var ...; | Test.kt:40:4:40:6 | <Expr>; |