From 33b807f3bb2dedef59e9d1760de4bd2bd1a27725 Mon Sep 17 00:00:00 2001
From: Chris Smowton <smowton@github.com>
Date: Wed, 13 Mar 2024 16:52:06 +0000
Subject: [PATCH] Parameters and local variables: add `isAnonymous` predicate

---
 java/ql/lib/semmle/code/java/Expr.qll     | 7 ++++++-
 java/ql/lib/semmle/code/java/Variable.qll | 7 +++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/java/ql/lib/semmle/code/java/Expr.qll b/java/ql/lib/semmle/code/java/Expr.qll
index 3442855a91a..315b4d19b9b 100644
--- a/java/ql/lib/semmle/code/java/Expr.qll
+++ b/java/ql/lib/semmle/code/java/Expr.qll
@@ -1691,6 +1691,9 @@ class LocalVariableDeclExpr extends Expr, @localvariabledeclexpr {
   /** Gets the name of the variable declared by this local variable declaration expression. */
   string getName() { result = this.getVariable().getName() }
 
+  /** Holds if this is an anonymous local variable, `_` */
+  predicate isAnonymous() { this.getName() = "" }
+
   /**
    * Gets the switch statement or expression whose pattern declares this identifier, if any.
    */
@@ -1763,7 +1766,9 @@ class LocalVariableDeclExpr extends Expr, @localvariabledeclexpr {
   }
 
   /** Gets a printable representation of this expression. */
-  override string toString() { result = this.getName() }
+  override string toString() {
+    if this.getName() = "" then result = "<anonymous local variable>" else result = this.getName()
+  }
 
   override string getAPrimaryQlClass() { result = "LocalVariableDeclExpr" }
 }
diff --git a/java/ql/lib/semmle/code/java/Variable.qll b/java/ql/lib/semmle/code/java/Variable.qll
index 8ed650d5f16..f28e378c233 100644
--- a/java/ql/lib/semmle/code/java/Variable.qll
+++ b/java/ql/lib/semmle/code/java/Variable.qll
@@ -117,4 +117,11 @@ class Parameter extends Element, @param, LocalScopeVariable {
   }
 
   override string getAPrimaryQlClass() { result = "Parameter" }
+
+  override string toString() {
+    if this.getName() = "" then result = "<anonymous parameter>" else result = super.toString()
+  }
+
+  /** Holds if this is an anonymous parameter, `_` */
+  predicate isAnonymous() { this.getName() = "" }
 }