Merge pull request #356 from asger-semmle/parameter-node

Approved by xiemaisi

javascript/ql/src/semmle/javascript/dataflow/DataFlow.qll

@@ -33,6 +33,9 @@ module DataFlow {
        ce.getMethodName() = kind and (kind = "call" or kind = "apply")
      }
   or TThisNode(StmtContainer f) { f.(Function).getThisBinder() = f or f instanceof TopLevel }
+  or TUnusedParameterNode(SimpleParameter p) {
+    not exists (SsaExplicitDefinition ssa | p = ssa.getDef())
+  }
 
   /**
    * A node in the data flow graph.
@@ -671,6 +674,37 @@ module DataFlow {
     override string getPropertyName() { none() }
   }
 
+  /**
+   * A data flow node representing an unused parameter.
+   *
+   * This case exists to ensure all parameters have a corresponding data-flow node.
+   * In most cases, parameters are represented by SSA definitions or destructuring pattern nodes.
+   */
+  private class UnusedParameterNode extends DataFlow::Node, TUnusedParameterNode {
+    SimpleParameter p;
+
+    UnusedParameterNode() {
+      this = TUnusedParameterNode(p)
+    }
+
+    override string toString() {
+      result = p.toString()
+    }
+
+    override ASTNode getAstNode() {
+      result = p
+    }
+
+    override BasicBlock getBasicBlock() {
+      result = p.getBasicBlock()
+    }
+
+    override predicate hasLocationInfo(string filepath, int startline, int startcolumn,
+                                       int endline, int endcolumn) {
+      p.getLocation().hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
+    }
+  }
+
   /**
    * Provides classes representing various kinds of calls.
    *
@@ -866,6 +900,8 @@ module DataFlow {
     )
     or
     nd = TDestructuringPatternNode(p)
+    or
+    nd = TUnusedParameterNode(p)
   }
 
   /**

javascript/ql/test/library-tests/DataFlow/parameters.expected

@@ -0,0 +1,7 @@
+| sources.js:1:6:1:6 | x |
+| sources.js:3:11:3:11 | x |
+| tst.js:16:13:16:13 | a |
+| tst.js:32:12:32:12 | b |
+| tst.js:87:11:87:24 | { p: x, ...o } |
+| tst.js:98:11:98:24 | [ x, ...rest ] |
+| tst.ts:13:39:13:38 | args |

javascript/ql/test/library-tests/DataFlow/parameters.ql

@@ -0,0 +1,4 @@
+import javascript
+
+from DataFlow::ParameterNode param
+select param

javascript/ql/test/library-tests/DataFlow/sources.expected

@@ -25,6 +25,7 @@
 | tst.js:28:2:29:3 | () =>\\n  x |
 | tst.js:32:1:32:0 | this |
 | tst.js:32:1:34:1 | functio ... ables\\n} |
+| tst.js:32:12:32:12 | b |
 | tst.js:35:1:35:7 | g(true) |
 | tst.js:37:9:42:1 | {\\n  x:  ... ;\\n  }\\n} |
 | tst.js:39:4:39:3 | this |

javascript/ql/test/library-tests/Promises/PromiseDefinition_getRejectParameter.expected

@@ -1 +1,4 @@
+| promises.js:3:17:5:4 | new Pro ... );\\n  }) | promises.js:3:48:3:53 | reject |
 | promises.js:10:18:17:4 | new Pro ... );\\n  }) | promises.js:10:36:10:38 | rej |
+| promises.js:33:19:35:6 | new Pro ... \\n    }) | promises.js:33:50:33:55 | reject |
+| promises.js:43:19:45:6 | Q.Promi ... \\n    }) | promises.js:43:48:43:53 | reject |

javascript/ql/test/library-tests/frameworks/ReactJS/ReactComponent_getADirectPropsSource.expected

@@ -5,12 +5,16 @@
 | namedImport.js:3:1:3:28 | class C ... nent {} | namedImport.js:3:27:3:26 | args |
 | namedImport.js:5:1:5:20 | class D extends C {} | namedImport.js:5:19:5:18 | args |
 | plainfn.js:1:1:3:1 | functio ... div>;\\n} | plainfn.js:1:16:1:20 | props |
+| plainfn.js:5:1:7:1 | functio ... iv");\\n} | plainfn.js:5:17:5:21 | props |
+| plainfn.js:9:1:12:1 | functio ... rn x;\\n} | plainfn.js:9:17:9:21 | props |
+| plainfn.js:20:1:24:1 | functio ... n 42;\\n} | plainfn.js:20:28:20:32 | props |
 | preact.js:1:1:7:1 | class H ...     }\\n} | preact.js:1:38:1:37 | args |
 | preact.js:1:1:7:1 | class H ...     }\\n} | preact.js:2:12:2:16 | props |
 | preact.js:9:1:11:1 | class H ... nt {\\n\\n} | preact.js:9:38:9:37 | args |
 | probably-a-component.js:1:1:6:1 | class H ...     }\\n} | probably-a-component.js:1:31:1:30 | args |
 | probably-a-component.js:1:1:6:1 | class H ...     }\\n} | probably-a-component.js:3:9:3:18 | this.props |
 | props.js:2:5:3:5 | class C ... {\\n    } | props.js:2:37:2:36 | args |
+| props.js:26:5:28:5 | functio ... ;\\n    } | props.js:26:16:26:20 | props |
 | statePropertyWrites.js:36:19:45:1 | {\\n  ren ... ;\\n  }\\n} | statePropertyWrites.js:38:24:38:33 | this.props |
 | thisAccesses.js:31:2:36:1 | functio ... iv/>;\\n} | thisAccesses.js:31:12:31:16 | props |
 | thisAccesses.js:47:1:52:1 | class C ...     }\\n} | thisAccesses.js:48:18:48:18 | y |