From 4fb138a1a3c899e5083648b81800c423f311cbce Mon Sep 17 00:00:00 2001
From: Tom Hvitved <hvitved@github.com>
Date: Mon, 31 Mar 2025 14:37:02 +0200
Subject: [PATCH] Rust: Make `Element.toString` non-recursive

---
 misc/codegen/templates/ql_class.mustache      |  6 +++++-
 rust/ql/.generated.list                       |  2 +-
 .../rust/elements/internal/ElementImpl.qll    |  1 +
 .../rust/elements/internal/ModuleImpl.qll     |  2 +-
 .../codeql/rust/elements/internal/UseImpl.qll |  2 +-
 .../rust/elements/internal/UseTreeImpl.qll    | 20 ++++++++++++++++---
 .../elements/internal/generated/Element.qll   |  6 +++++-
 7 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/misc/codegen/templates/ql_class.mustache b/misc/codegen/templates/ql_class.mustache
index 39aba2b1ef4..e80e0b0eebd 100644
--- a/misc/codegen/templates/ql_class.mustache
+++ b/misc/codegen/templates/ql_class.mustache
@@ -30,7 +30,11 @@ module Generated {
      * Gets the string representation of this element.
      */
     cached
-    final string toString() { result = this.toStringImpl() }
+    final string toString() {
+      result = this.toStringImpl() and
+      // recursion guard to prevent `toString` from being defined recursively
+      (exists(any(Element e).toStringImpl()) implies any())
+    }
 
     /**
      * INTERNAL: Do not use.
diff --git a/rust/ql/.generated.list b/rust/ql/.generated.list
index 61529b8b6cc..0bd2931256e 100644
--- a/rust/ql/.generated.list
+++ b/rust/ql/.generated.list
@@ -506,7 +506,7 @@ lib/codeql/rust/elements/internal/generated/ConstParam.qll 310342603959a4d521418
 lib/codeql/rust/elements/internal/generated/ContinueExpr.qll e2010feb14fb6edeb83a991d9357e50edb770172ddfde2e8670b0d3e68169f28 48d09d661e1443002f6d22b8710e22c9c36d9daa9cde09c6366a61e960d717cb
 lib/codeql/rust/elements/internal/generated/Crate.qll d245f24e9da4f180c526a6d092f554a9577bae7225c81c36a391947c0865eeb3 c95dbb32b2ce4d9664be56c95b19fcd01c2d3244385e55151f9b06b07f04ce9b
 lib/codeql/rust/elements/internal/generated/DynTraitTypeRepr.qll a9d540717af1f00dbea1c683fd6b846cddfb2968c7f3e021863276f123337787 1972efb9bca7aae9a9708ca6dcf398e5e8c6d2416a07d525dba1649b80fbe4d1
-lib/codeql/rust/elements/internal/generated/Element.qll 69ce882811f2bef7e0a93c0a24494dd16120a108ba4180d455344e29144a98c4 7781bc5c69b5b08775902fcb97cb23f85359ef2303545afe9d44301b19024b3a
+lib/codeql/rust/elements/internal/generated/Element.qll d56d22c060fa929464f837b1e16475a4a2a2e42d68235a014f7369bcb48431db 0e48426ca72179f675ac29aa49bbaadb8b1d27b08ad5cbc72ec5a005c291848e
 lib/codeql/rust/elements/internal/generated/Enum.qll 4f4cbc9cd758c20d476bc767b916c62ba434d1750067d0ffb63e0821bb95ec86 3da735d54022add50cec0217bbf8ec4cf29b47f4851ee327628bcdd6454989d0
 lib/codeql/rust/elements/internal/generated/Expr.qll 5fa34f2ed21829a1509417440dae42d416234ff43433002974328e7aabb8f30f 46f3972c7413b7db28a3ea8acb5a50a74b6dd9b658e8725f6953a8829ac912f8
 lib/codeql/rust/elements/internal/generated/ExprStmt.qll d1112230015fbeb216b43407a268dc2ccd0f9e0836ab2dca4800c51b38fa1d7d 4a80562dcc55efa5e72c6c3b1d6747ab44fe494e76faff2b8f6e9f10a4b08b5b
diff --git a/rust/ql/lib/codeql/rust/elements/internal/ElementImpl.qll b/rust/ql/lib/codeql/rust/elements/internal/ElementImpl.qll
index 75de7703df0..7a464a378d1 100644
--- a/rust/ql/lib/codeql/rust/elements/internal/ElementImpl.qll
+++ b/rust/ql/lib/codeql/rust/elements/internal/ElementImpl.qll
@@ -20,6 +20,7 @@ module Impl {
      * Returns a string suitable to be inserted into the name of the parent. Typically `"..."`,
      * but may be overridden by subclasses.
      */
+    pragma[nomagic]
     string toAbbreviatedString() { result = "..." }
 
     predicate isUnknown() { none() } // compatibility with test generation, to be fixed
diff --git a/rust/ql/lib/codeql/rust/elements/internal/ModuleImpl.qll b/rust/ql/lib/codeql/rust/elements/internal/ModuleImpl.qll
index 0fb9690d2d1..19f63f0790f 100644
--- a/rust/ql/lib/codeql/rust/elements/internal/ModuleImpl.qll
+++ b/rust/ql/lib/codeql/rust/elements/internal/ModuleImpl.qll
@@ -24,6 +24,6 @@ module Impl {
    * ```
    */
   class Module extends Generated::Module {
-    override string toStringImpl() { result = "mod " + this.getName() }
+    override string toStringImpl() { result = "mod " + this.getName().getText() }
   }
 }
diff --git a/rust/ql/lib/codeql/rust/elements/internal/UseImpl.qll b/rust/ql/lib/codeql/rust/elements/internal/UseImpl.qll
index 5c2567fc3d7..7b99c609a46 100644
--- a/rust/ql/lib/codeql/rust/elements/internal/UseImpl.qll
+++ b/rust/ql/lib/codeql/rust/elements/internal/UseImpl.qll
@@ -19,6 +19,6 @@ module Impl {
    * ```
    */
   class Use extends Generated::Use {
-    override string toStringImpl() { result = "use " + this.getUseTree() }
+    override string toStringImpl() { result = "use " + this.getUseTree().toAbbreviatedString() }
   }
 }
diff --git a/rust/ql/lib/codeql/rust/elements/internal/UseTreeImpl.qll b/rust/ql/lib/codeql/rust/elements/internal/UseTreeImpl.qll
index ef1be77ef78..7e917268a72 100644
--- a/rust/ql/lib/codeql/rust/elements/internal/UseTreeImpl.qll
+++ b/rust/ql/lib/codeql/rust/elements/internal/UseTreeImpl.qll
@@ -26,14 +26,28 @@ module Impl {
       result = strictconcat(int i | | this.toStringPart(i) order by i)
     }
 
-    private string toStringPart(int index) {
-      result = this.getPath().toStringImpl() and index = 0
-      or
+    private string toStringPartCommon(int index) {
       result = "::{...}" and this.hasUseTreeList() and index = 1
       or
       result = "::*" and this.isGlob() and index = 2
       or
       result = " as " + this.getRename().getName().getText() and index = 3
     }
+
+    private string toStringPart(int index) {
+      result = this.getPath().toStringImpl() and index = 0
+      or
+      result = this.toStringPartCommon(index)
+    }
+
+    override string toAbbreviatedString() {
+      result = strictconcat(int i | | this.toAbbreviatedStringPart(i) order by i)
+    }
+
+    private string toAbbreviatedStringPart(int index) {
+      result = this.getPath().toAbbreviatedString() and index = 0
+      or
+      result = this.toStringPartCommon(index)
+    }
   }
 }
diff --git a/rust/ql/lib/codeql/rust/elements/internal/generated/Element.qll b/rust/ql/lib/codeql/rust/elements/internal/generated/Element.qll
index f8a5f4b24b2..9e3db0fe8b6 100644
--- a/rust/ql/lib/codeql/rust/elements/internal/generated/Element.qll
+++ b/rust/ql/lib/codeql/rust/elements/internal/generated/Element.qll
@@ -24,7 +24,11 @@ module Generated {
      * Gets the string representation of this element.
      */
     cached
-    final string toString() { result = this.toStringImpl() }
+    final string toString() {
+      result = this.toStringImpl() and
+      // recursion guard to prevent `toString` from being defined recursively
+      (exists(any(Element e).toStringImpl()) implies any())
+    }
 
     /**
      * INTERNAL: Do not use.