From 84accd1c81846043ea1c42816f36b259ef99de97 Mon Sep 17 00:00:00 2001
From: Simon Friis Vindum <simonfv@gmail.com>
Date: Fri, 20 Jun 2025 16:12:53 +0200
Subject: [PATCH 1/4] Rust: Implement overloaded index expression in type
 inference

---
 .../rust/dataflow/internal/DataFlowImpl.qll   |  6 +-
 .../rust/elements/internal/CallImpl.qll       | 16 ++++
 .../codeql/rust/internal/TypeInference.qll    | 77 ++++++++++---------
 .../test/library-tests/type-inference/main.rs |  8 +-
 .../type-inference/type-inference.expected    | 73 ++----------------
 5 files changed, 69 insertions(+), 111 deletions(-)

diff --git a/rust/ql/lib/codeql/rust/dataflow/internal/DataFlowImpl.qll b/rust/ql/lib/codeql/rust/dataflow/internal/DataFlowImpl.qll
index 59ff2fc24c22..20c9e80b87aa 100644
--- a/rust/ql/lib/codeql/rust/dataflow/internal/DataFlowImpl.qll
+++ b/rust/ql/lib/codeql/rust/dataflow/internal/DataFlowImpl.qll
@@ -959,7 +959,11 @@ private module Cached {
 
   cached
   newtype TDataFlowCall =
-    TCall(CallCfgNode c) { Stages::DataFlowStage::ref() } or
+    TCall(CallCfgNode c) {
+      Stages::DataFlowStage::ref() and
+      // TODO: Handle index expressions as calls in data flow.
+      not c.getCall() instanceof IndexExpr
+    } or
     TSummaryCall(
       FlowSummaryImpl::Public::SummarizedCallable c, FlowSummaryImpl::Private::SummaryNode receiver
     ) {
diff --git a/rust/ql/lib/codeql/rust/elements/internal/CallImpl.qll b/rust/ql/lib/codeql/rust/elements/internal/CallImpl.qll
index f350e88efad8..9cd45ca76709 100644
--- a/rust/ql/lib/codeql/rust/elements/internal/CallImpl.qll
+++ b/rust/ql/lib/codeql/rust/elements/internal/CallImpl.qll
@@ -160,4 +160,20 @@ module Impl {
       pos.asPosition() = 0 and result = super.getOperand(1)
     }
   }
+
+  private class IndexCall extends Call instanceof IndexExpr {
+    override string getMethodName() { result = "index" }
+
+    override Trait getTrait() { result.getCanonicalPath() = "core::ops::index::Index" }
+
+    override predicate implicitBorrowAt(ArgumentPosition pos, boolean certain) {
+      pos.isSelf() and certain = true
+    }
+
+    override Expr getArgument(ArgumentPosition pos) {
+      pos.isSelf() and result = super.getBase()
+      or
+      pos.asPosition() = 0 and result = super.getIndex()
+    }
+  }
 }
diff --git a/rust/ql/lib/codeql/rust/internal/TypeInference.qll b/rust/ql/lib/codeql/rust/internal/TypeInference.qll
index b560ac5ec8c1..04cb6b2c4840 100644
--- a/rust/ql/lib/codeql/rust/internal/TypeInference.qll
+++ b/rust/ql/lib/codeql/rust/internal/TypeInference.qll
@@ -772,45 +772,48 @@ private Type inferCallExprBaseType(AstNode n, TypePath path) {
     n = a.getNodeAt(apos) and
     result = CallExprBaseMatching::inferAccessType(a, apos, path0)
   |
-    (
+    if
       apos.isBorrowed(true)
       or
-      // The desugaring of the unary `*e` is `*Deref::deref(&e)`. To handle the
-      // deref expression after the call we must strip a `&` from the type at
-      // the return position.
-      apos.isReturn() and a instanceof DerefExpr
-    ) and
-    path0.isCons(TRefTypeParameter(), path)
-    or
-    apos.isBorrowed(false) and
-    exists(Type argType | argType = inferType(n) |
-      if argType = TRefType()
+      // The desugaring of the unary `*e` is `*Deref::deref(&e)` and the
+      // desugaring of `a[b]` is `*Index::index(&a, b)`. To handle the deref
+      // expression after the call we must strip a `&` from the type at the
+      // return position.
+      apos.isReturn() and
+      (a instanceof DerefExpr or a instanceof IndexExpr)
+    then path0.isCons(TRefTypeParameter(), path)
+    else
+      if apos.isBorrowed(false)
       then
-        path = path0 and
-        path0.isCons(TRefTypeParameter(), _)
-        or
-        // adjust for implicit deref
-        not path0.isCons(TRefTypeParameter(), _) and
-        not (path0.isEmpty() and result = TRefType()) and
-        path = TypePath::cons(TRefTypeParameter(), path0)
-      else (
-        not (
-          argType.(StructType).asItemNode() instanceof StringStruct and
-          result.(StructType).asItemNode() instanceof Builtins::Str
-        ) and
-        (
-          not path0.isCons(TRefTypeParameter(), _) and
-          not (path0.isEmpty() and result = TRefType()) and
-          path = path0
-          or
-          // adjust for implicit borrow
-          path0.isCons(TRefTypeParameter(), path)
+        exists(Type argType | argType = inferType(n) |
+          if argType = TRefType()
+          then
+            path = path0 and
+            path0.isCons(TRefTypeParameter(), _)
+            or
+            // adjust for implicit deref
+            not path0.isCons(TRefTypeParameter(), _) and
+            not (path0.isEmpty() and result = TRefType()) and
+            path = TypePath::cons(TRefTypeParameter(), path0)
+          else (
+            not (
+              argType.(StructType).asItemNode() instanceof StringStruct and
+              result.(StructType).asItemNode() instanceof Builtins::Str
+            ) and
+            (
+              not path0.isCons(TRefTypeParameter(), _) and
+              not (path0.isEmpty() and result = TRefType()) and
+              path = path0
+              or
+              // adjust for implicit borrow
+              path0.isCons(TRefTypeParameter(), path)
+            )
+          )
         )
+      else (
+        not apos.isBorrowed(_) and
+        path = path0
       )
-    )
-    or
-    not apos.isBorrowed(_) and
-    path = path0
   )
 }
 
@@ -1116,8 +1119,8 @@ private class Vec extends Struct {
  */
 pragma[nomagic]
 private Type inferIndexExprType(IndexExpr ie, TypePath path) {
-  // TODO: Should be implemented as method resolution, using the special
-  // `std::ops::Index` trait.
+  // TODO: Method resolution to the `std::ops::Index` trait can handle the
+  // `Index` instances for slices and arrays.
   exists(TypePath exprPath, Builtins::BuiltinType t |
     TStruct(t) = inferType(ie.getIndex()) and
     (
@@ -1129,8 +1132,6 @@ private Type inferIndexExprType(IndexExpr ie, TypePath path) {
     ) and
     result = inferType(ie.getBase(), exprPath)
   |
-    exprPath.isCons(any(Vec v).getElementTypeParameter(), path)
-    or
     exprPath.isCons(any(ArrayTypeParameter tp), path)
     or
     exists(TypePath path0 |
diff --git a/rust/ql/test/library-tests/type-inference/main.rs b/rust/ql/test/library-tests/type-inference/main.rs
index 109581588a58..a963e2e0edc8 100644
--- a/rust/ql/test/library-tests/type-inference/main.rs
+++ b/rust/ql/test/library-tests/type-inference/main.rs
@@ -1856,21 +1856,21 @@ mod indexers {
 
         // MyVec::index
         fn index(&self, index: usize) -> &Self::Output {
-            &self.data[index] // $ fieldof=MyVec
+            &self.data[index] // $ fieldof=MyVec method=index
         }
     }
 
     fn analyze_slice(slice: &[S]) {
-        let x = slice[0].foo(); // $ method=foo type=x:S
+        let x = slice[0].foo(); // $ method=foo type=x:S method=index
     }
 
     pub fn f() {
         let mut vec = MyVec::new(); // $ type=vec:T.S
         vec.push(S); // $ method=push
-        vec[0].foo(); // $ MISSING: method=foo -- type inference does not support the `Index` trait yet
+        vec[0].foo(); // $ method=MyVec::index method=foo
 
         let xs: [S; 1] = [S];
-        let x = xs[0].foo(); // $ method=foo type=x:S
+        let x = xs[0].foo(); // $ method=foo type=x:S method=index
 
         analyze_slice(&xs);
     }
diff --git a/rust/ql/test/library-tests/type-inference/type-inference.expected b/rust/ql/test/library-tests/type-inference/type-inference.expected
index 3a628ac5c962..35df5930a5cc 100644
--- a/rust/ql/test/library-tests/type-inference/type-inference.expected
+++ b/rust/ql/test/library-tests/type-inference/type-inference.expected
@@ -31,23 +31,15 @@ inferType
 | dereference.rs:36:14:36:42 | MyIntPointer {...} |  | dereference.rs:4:1:6:1 | MyIntPointer |
 | dereference.rs:36:36:36:40 | 34i64 |  | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:37:9:37:11 | _b2 |  | {EXTERNAL LOCATION} | i64 |
-| dereference.rs:37:9:37:11 | _b2 |  | file://:0:0:0:0 | & |
-| dereference.rs:37:9:37:11 | _b2 | &T | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:37:15:37:17 | * ... |  | {EXTERNAL LOCATION} | i64 |
-| dereference.rs:37:15:37:17 | * ... |  | file://:0:0:0:0 | & |
-| dereference.rs:37:15:37:17 | * ... | &T | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:37:16:37:17 | a2 |  | dereference.rs:4:1:6:1 | MyIntPointer |
 | dereference.rs:40:9:40:10 | a3 |  | dereference.rs:4:1:6:1 | MyIntPointer |
 | dereference.rs:40:14:40:42 | MyIntPointer {...} |  | dereference.rs:4:1:6:1 | MyIntPointer |
 | dereference.rs:40:36:40:40 | 34i64 |  | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:41:9:41:11 | _b3 |  | {EXTERNAL LOCATION} | bool |
 | dereference.rs:41:15:41:19 | (...) |  | {EXTERNAL LOCATION} | i64 |
-| dereference.rs:41:15:41:19 | (...) |  | file://:0:0:0:0 | & |
-| dereference.rs:41:15:41:19 | (...) | &T | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:41:15:41:33 | ... .is_positive() |  | {EXTERNAL LOCATION} | bool |
 | dereference.rs:41:16:41:18 | * ... |  | {EXTERNAL LOCATION} | i64 |
-| dereference.rs:41:16:41:18 | * ... |  | file://:0:0:0:0 | & |
-| dereference.rs:41:16:41:18 | * ... | &T | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:41:17:41:18 | a3 |  | dereference.rs:4:1:6:1 | MyIntPointer |
 | dereference.rs:46:9:46:10 | c1 |  | dereference.rs:17:1:19:1 | MySmartPointer |
 | dereference.rs:46:9:46:10 | c1 | T | {EXTERNAL LOCATION} | char |
@@ -66,11 +58,7 @@ inferType
 | dereference.rs:50:14:50:42 | MySmartPointer {...} | T | {EXTERNAL LOCATION} | char |
 | dereference.rs:50:38:50:40 | 'a' |  | {EXTERNAL LOCATION} | char |
 | dereference.rs:51:9:51:11 | _d2 |  | {EXTERNAL LOCATION} | char |
-| dereference.rs:51:9:51:11 | _d2 |  | file://:0:0:0:0 | & |
-| dereference.rs:51:9:51:11 | _d2 | &T | {EXTERNAL LOCATION} | char |
 | dereference.rs:51:15:51:17 | * ... |  | {EXTERNAL LOCATION} | char |
-| dereference.rs:51:15:51:17 | * ... |  | file://:0:0:0:0 | & |
-| dereference.rs:51:15:51:17 | * ... | &T | {EXTERNAL LOCATION} | char |
 | dereference.rs:51:16:51:17 | c2 |  | dereference.rs:17:1:19:1 | MySmartPointer |
 | dereference.rs:51:16:51:17 | c2 | T | {EXTERNAL LOCATION} | char |
 | dereference.rs:54:9:54:10 | c3 |  | dereference.rs:17:1:19:1 | MySmartPointer |
@@ -80,12 +68,8 @@ inferType
 | dereference.rs:54:38:54:42 | 34i64 |  | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:55:9:55:11 | _d3 |  | {EXTERNAL LOCATION} | bool |
 | dereference.rs:55:15:55:19 | (...) |  | {EXTERNAL LOCATION} | i64 |
-| dereference.rs:55:15:55:19 | (...) |  | file://:0:0:0:0 | & |
-| dereference.rs:55:15:55:19 | (...) | &T | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:55:15:55:33 | ... .is_positive() |  | {EXTERNAL LOCATION} | bool |
 | dereference.rs:55:16:55:18 | * ... |  | {EXTERNAL LOCATION} | i64 |
-| dereference.rs:55:16:55:18 | * ... |  | file://:0:0:0:0 | & |
-| dereference.rs:55:16:55:18 | * ... | &T | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:55:17:55:18 | c3 |  | dereference.rs:17:1:19:1 | MySmartPointer |
 | dereference.rs:55:17:55:18 | c3 | T | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:60:9:60:10 | e1 |  | file://:0:0:0:0 | & |
@@ -107,11 +91,7 @@ inferType
 | dereference.rs:64:14:64:17 | &'a' | &T | {EXTERNAL LOCATION} | char |
 | dereference.rs:64:15:64:17 | 'a' |  | {EXTERNAL LOCATION} | char |
 | dereference.rs:65:9:65:11 | _f2 |  | {EXTERNAL LOCATION} | char |
-| dereference.rs:65:9:65:11 | _f2 |  | file://:0:0:0:0 | & |
-| dereference.rs:65:9:65:11 | _f2 | &T | {EXTERNAL LOCATION} | char |
 | dereference.rs:65:15:65:17 | * ... |  | {EXTERNAL LOCATION} | char |
-| dereference.rs:65:15:65:17 | * ... |  | file://:0:0:0:0 | & |
-| dereference.rs:65:15:65:17 | * ... | &T | {EXTERNAL LOCATION} | char |
 | dereference.rs:65:16:65:17 | e2 |  | file://:0:0:0:0 | & |
 | dereference.rs:65:16:65:17 | e2 | &T | {EXTERNAL LOCATION} | char |
 | dereference.rs:68:9:68:10 | e3 |  | file://:0:0:0:0 | & |
@@ -121,12 +101,8 @@ inferType
 | dereference.rs:68:15:68:19 | 34i64 |  | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:69:9:69:11 | _f3 |  | {EXTERNAL LOCATION} | bool |
 | dereference.rs:69:15:69:19 | (...) |  | {EXTERNAL LOCATION} | i64 |
-| dereference.rs:69:15:69:19 | (...) |  | file://:0:0:0:0 | & |
-| dereference.rs:69:15:69:19 | (...) | &T | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:69:15:69:33 | ... .is_positive() |  | {EXTERNAL LOCATION} | bool |
 | dereference.rs:69:16:69:18 | * ... |  | {EXTERNAL LOCATION} | i64 |
-| dereference.rs:69:16:69:18 | * ... |  | file://:0:0:0:0 | & |
-| dereference.rs:69:16:69:18 | * ... | &T | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:69:17:69:18 | e3 |  | file://:0:0:0:0 | & |
 | dereference.rs:69:17:69:18 | e3 | &T | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:74:9:74:10 | g1 |  | {EXTERNAL LOCATION} | Box |
@@ -151,11 +127,7 @@ inferType
 | dereference.rs:78:25:78:37 | ...::new(...) | T | {EXTERNAL LOCATION} | char |
 | dereference.rs:78:34:78:36 | 'a' |  | {EXTERNAL LOCATION} | char |
 | dereference.rs:79:9:79:11 | _h2 |  | {EXTERNAL LOCATION} | char |
-| dereference.rs:79:9:79:11 | _h2 |  | file://:0:0:0:0 | & |
-| dereference.rs:79:9:79:11 | _h2 | &T | {EXTERNAL LOCATION} | char |
 | dereference.rs:79:15:79:17 | * ... |  | {EXTERNAL LOCATION} | char |
-| dereference.rs:79:15:79:17 | * ... |  | file://:0:0:0:0 | & |
-| dereference.rs:79:15:79:17 | * ... | &T | {EXTERNAL LOCATION} | char |
 | dereference.rs:79:16:79:17 | g2 |  | {EXTERNAL LOCATION} | Box |
 | dereference.rs:79:16:79:17 | g2 | A | {EXTERNAL LOCATION} | Global |
 | dereference.rs:79:16:79:17 | g2 | T | {EXTERNAL LOCATION} | char |
@@ -168,12 +140,8 @@ inferType
 | dereference.rs:82:33:82:37 | 34i64 |  | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:83:9:83:11 | _h3 |  | {EXTERNAL LOCATION} | bool |
 | dereference.rs:83:15:83:19 | (...) |  | {EXTERNAL LOCATION} | i64 |
-| dereference.rs:83:15:83:19 | (...) |  | file://:0:0:0:0 | & |
-| dereference.rs:83:15:83:19 | (...) | &T | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:83:15:83:33 | ... .is_positive() |  | {EXTERNAL LOCATION} | bool |
 | dereference.rs:83:16:83:18 | * ... |  | {EXTERNAL LOCATION} | i64 |
-| dereference.rs:83:16:83:18 | * ... |  | file://:0:0:0:0 | & |
-| dereference.rs:83:16:83:18 | * ... | &T | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:83:17:83:18 | g3 |  | {EXTERNAL LOCATION} | Box |
 | dereference.rs:83:17:83:18 | g3 | A | {EXTERNAL LOCATION} | Global |
 | dereference.rs:83:17:83:18 | g3 | T | {EXTERNAL LOCATION} | i64 |
@@ -2372,27 +2340,15 @@ inferType
 | main.rs:1109:29:1109:33 | SelfParam | &T | main.rs:1082:5:1085:5 | MyInt |
 | main.rs:1109:29:1109:33 | SelfParam | &T.&T | main.rs:1082:5:1085:5 | MyInt |
 | main.rs:1109:43:1111:9 | { ... } |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1110:13:1110:22 | (...) |  | file://:0:0:0:0 | & |
 | main.rs:1110:13:1110:22 | (...) |  | main.rs:1082:5:1085:5 | MyInt |
-| main.rs:1110:13:1110:22 | (...) | &T | file://:0:0:0:0 | & |
-| main.rs:1110:13:1110:22 | (...) | &T | main.rs:1082:5:1085:5 | MyInt |
-| main.rs:1110:13:1110:22 | (...) | &T.&T | main.rs:1082:5:1085:5 | MyInt |
 | main.rs:1110:13:1110:24 | ... .a |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1110:14:1110:21 | * ... |  | file://:0:0:0:0 | & |
 | main.rs:1110:14:1110:21 | * ... |  | main.rs:1082:5:1085:5 | MyInt |
-| main.rs:1110:14:1110:21 | * ... | &T | file://:0:0:0:0 | & |
-| main.rs:1110:14:1110:21 | * ... | &T | main.rs:1082:5:1085:5 | MyInt |
-| main.rs:1110:14:1110:21 | * ... | &T.&T | main.rs:1082:5:1085:5 | MyInt |
 | main.rs:1110:15:1110:21 | (...) |  | file://:0:0:0:0 | & |
 | main.rs:1110:15:1110:21 | (...) |  | main.rs:1082:5:1085:5 | MyInt |
-| main.rs:1110:15:1110:21 | (...) | &T | file://:0:0:0:0 | & |
 | main.rs:1110:15:1110:21 | (...) | &T | main.rs:1082:5:1085:5 | MyInt |
-| main.rs:1110:15:1110:21 | (...) | &T.&T | main.rs:1082:5:1085:5 | MyInt |
 | main.rs:1110:16:1110:20 | * ... |  | file://:0:0:0:0 | & |
 | main.rs:1110:16:1110:20 | * ... |  | main.rs:1082:5:1085:5 | MyInt |
-| main.rs:1110:16:1110:20 | * ... | &T | file://:0:0:0:0 | & |
 | main.rs:1110:16:1110:20 | * ... | &T | main.rs:1082:5:1085:5 | MyInt |
-| main.rs:1110:16:1110:20 | * ... | &T.&T | main.rs:1082:5:1085:5 | MyInt |
 | main.rs:1110:17:1110:20 | self |  | file://:0:0:0:0 | & |
 | main.rs:1110:17:1110:20 | self | &T | file://:0:0:0:0 | & |
 | main.rs:1110:17:1110:20 | self | &T | main.rs:1082:5:1085:5 | MyInt |
@@ -2400,13 +2356,9 @@ inferType
 | main.rs:1114:33:1114:36 | SelfParam |  | file://:0:0:0:0 | & |
 | main.rs:1114:33:1114:36 | SelfParam | &T | main.rs:1082:5:1085:5 | MyInt |
 | main.rs:1114:46:1116:9 | { ... } |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1115:13:1115:19 | (...) |  | file://:0:0:0:0 | & |
 | main.rs:1115:13:1115:19 | (...) |  | main.rs:1082:5:1085:5 | MyInt |
-| main.rs:1115:13:1115:19 | (...) | &T | main.rs:1082:5:1085:5 | MyInt |
 | main.rs:1115:13:1115:21 | ... .a |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1115:14:1115:18 | * ... |  | file://:0:0:0:0 | & |
 | main.rs:1115:14:1115:18 | * ... |  | main.rs:1082:5:1085:5 | MyInt |
-| main.rs:1115:14:1115:18 | * ... | &T | main.rs:1082:5:1085:5 | MyInt |
 | main.rs:1115:15:1115:18 | self |  | file://:0:0:0:0 | & |
 | main.rs:1115:15:1115:18 | self | &T | main.rs:1082:5:1085:5 | MyInt |
 | main.rs:1120:13:1120:14 | x1 |  | main.rs:1076:5:1077:19 | S |
@@ -2504,16 +2456,10 @@ inferType
 | main.rs:1143:19:1143:23 | S(...) | T | main.rs:1079:5:1080:14 | S2 |
 | main.rs:1143:21:1143:22 | S2 |  | main.rs:1079:5:1080:14 | S2 |
 | main.rs:1146:18:1146:23 | "{:?}\\n" |  | {EXTERNAL LOCATION} | str |
-| main.rs:1146:26:1146:30 | (...) |  | file://:0:0:0:0 | & |
 | main.rs:1146:26:1146:30 | (...) |  | main.rs:1076:5:1077:19 | S |
-| main.rs:1146:26:1146:30 | (...) | &T | main.rs:1076:5:1077:19 | S |
-| main.rs:1146:26:1146:30 | (...) | &T.T | main.rs:1079:5:1080:14 | S2 |
 | main.rs:1146:26:1146:30 | (...) | T | main.rs:1079:5:1080:14 | S2 |
 | main.rs:1146:26:1146:35 | ... .m1() |  | main.rs:1079:5:1080:14 | S2 |
-| main.rs:1146:27:1146:29 | * ... |  | file://:0:0:0:0 | & |
 | main.rs:1146:27:1146:29 | * ... |  | main.rs:1076:5:1077:19 | S |
-| main.rs:1146:27:1146:29 | * ... | &T | main.rs:1076:5:1077:19 | S |
-| main.rs:1146:27:1146:29 | * ... | &T.T | main.rs:1079:5:1080:14 | S2 |
 | main.rs:1146:27:1146:29 | * ... | T | main.rs:1079:5:1080:14 | S2 |
 | main.rs:1146:28:1146:29 | x6 |  | file://:0:0:0:0 | & |
 | main.rs:1146:28:1146:29 | x6 | &T | main.rs:1076:5:1077:19 | S |
@@ -2739,20 +2685,10 @@ inferType
 | main.rs:1251:15:1251:16 | &x | &T | main.rs:1227:5:1227:13 | S |
 | main.rs:1251:16:1251:16 | x |  | main.rs:1227:5:1227:13 | S |
 | main.rs:1253:13:1253:13 | n |  | {EXTERNAL LOCATION} | bool |
-| main.rs:1253:13:1253:13 | n |  | file://:0:0:0:0 | & |
-| main.rs:1253:13:1253:13 | n | &T | {EXTERNAL LOCATION} | bool |
-| main.rs:1253:13:1253:13 | n | &T | file://:0:0:0:0 | & |
-| main.rs:1253:13:1253:13 | n | &T.&T | {EXTERNAL LOCATION} | bool |
 | main.rs:1253:17:1253:24 | * ... |  | {EXTERNAL LOCATION} | bool |
-| main.rs:1253:17:1253:24 | * ... |  | file://:0:0:0:0 | & |
-| main.rs:1253:17:1253:24 | * ... | &T | {EXTERNAL LOCATION} | bool |
-| main.rs:1253:17:1253:24 | * ... | &T | file://:0:0:0:0 | & |
-| main.rs:1253:17:1253:24 | * ... | &T.&T | {EXTERNAL LOCATION} | bool |
 | main.rs:1253:18:1253:24 | * ... |  | {EXTERNAL LOCATION} | bool |
 | main.rs:1253:18:1253:24 | * ... |  | file://:0:0:0:0 | & |
 | main.rs:1253:18:1253:24 | * ... | &T | {EXTERNAL LOCATION} | bool |
-| main.rs:1253:18:1253:24 | * ... | &T | file://:0:0:0:0 | & |
-| main.rs:1253:18:1253:24 | * ... | &T.&T | {EXTERNAL LOCATION} | bool |
 | main.rs:1253:19:1253:24 | &... |  | file://:0:0:0:0 | & |
 | main.rs:1253:19:1253:24 | &... | &T | {EXTERNAL LOCATION} | bool |
 | main.rs:1253:19:1253:24 | &... | &T | file://:0:0:0:0 | & |
@@ -3863,10 +3799,12 @@ inferType
 | main.rs:1859:14:1859:29 | ...[index] |  | main.rs:1854:10:1854:10 | T |
 | main.rs:1859:24:1859:28 | index |  | {EXTERNAL LOCATION} | usize |
 | main.rs:1863:22:1863:26 | slice |  | file://:0:0:0:0 | & |
+| main.rs:1863:22:1863:26 | slice |  | file://:0:0:0:0 | [] |
 | main.rs:1863:22:1863:26 | slice | &T | file://:0:0:0:0 | [] |
 | main.rs:1863:22:1863:26 | slice | &T.[T] | main.rs:1830:5:1831:13 | S |
 | main.rs:1864:13:1864:13 | x |  | main.rs:1830:5:1831:13 | S |
 | main.rs:1864:17:1864:21 | slice |  | file://:0:0:0:0 | & |
+| main.rs:1864:17:1864:21 | slice |  | file://:0:0:0:0 | [] |
 | main.rs:1864:17:1864:21 | slice | &T | file://:0:0:0:0 | [] |
 | main.rs:1864:17:1864:21 | slice | &T.[T] | main.rs:1830:5:1831:13 | S |
 | main.rs:1864:17:1864:24 | slice[0] |  | main.rs:1830:5:1831:13 | S |
@@ -3881,7 +3819,10 @@ inferType
 | main.rs:1869:18:1869:18 | S |  | main.rs:1830:5:1831:13 | S |
 | main.rs:1870:9:1870:11 | vec |  | main.rs:1839:5:1842:5 | MyVec |
 | main.rs:1870:9:1870:11 | vec | T | main.rs:1830:5:1831:13 | S |
+| main.rs:1870:9:1870:14 | vec[0] |  | main.rs:1830:5:1831:13 | S |
+| main.rs:1870:9:1870:20 | ... .foo() |  | main.rs:1830:5:1831:13 | S |
 | main.rs:1870:13:1870:13 | 0 |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1870:13:1870:13 | 0 |  | {EXTERNAL LOCATION} | usize |
 | main.rs:1872:13:1872:14 | xs |  | file://:0:0:0:0 | [] |
 | main.rs:1872:13:1872:14 | xs |  | file://:0:0:0:0 | [] |
 | main.rs:1872:13:1872:14 | xs | [T;...] | main.rs:1830:5:1831:13 | S |
@@ -3926,11 +3867,7 @@ inferType
 | main.rs:1899:26:1899:30 | value |  | file://:0:0:0:0 | & |
 | main.rs:1899:26:1899:30 | value | &T | {EXTERNAL LOCATION} | i64 |
 | main.rs:1899:47:1901:9 | { ... } |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1899:47:1901:9 | { ... } |  | file://:0:0:0:0 | & |
-| main.rs:1899:47:1901:9 | { ... } | &T | {EXTERNAL LOCATION} | i64 |
 | main.rs:1900:13:1900:18 | * ... |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1900:13:1900:18 | * ... |  | file://:0:0:0:0 | & |
-| main.rs:1900:13:1900:18 | * ... | &T | {EXTERNAL LOCATION} | i64 |
 | main.rs:1900:14:1900:18 | value |  | file://:0:0:0:0 | & |
 | main.rs:1900:14:1900:18 | value | &T | {EXTERNAL LOCATION} | i64 |
 | main.rs:1906:19:1906:23 | SelfParam |  | file://:0:0:0:0 | & |

From 846ef9ad5a2ff76ef6cac17c775e0342b1ac71b2 Mon Sep 17 00:00:00 2001
From: Simon Friis Vindum <simonfv@gmail.com>
Date: Fri, 20 Jun 2025 16:18:05 +0200
Subject: [PATCH 2/4] Rust: Document spurious type

---
 .../test/library-tests/type-inference/main.rs |   8 +-
 .../type-inference/type-inference.expected    | 214 +++++++++---------
 2 files changed, 114 insertions(+), 108 deletions(-)

diff --git a/rust/ql/test/library-tests/type-inference/main.rs b/rust/ql/test/library-tests/type-inference/main.rs
index a963e2e0edc8..18af89be3ab7 100644
--- a/rust/ql/test/library-tests/type-inference/main.rs
+++ b/rust/ql/test/library-tests/type-inference/main.rs
@@ -1861,7 +1861,13 @@ mod indexers {
     }
 
     fn analyze_slice(slice: &[S]) {
-        let x = slice[0].foo(); // $ method=foo type=x:S method=index
+        // NOTE: `slice` gets the spurious type `[]` because the desugaring of
+        // the index expression adds an implicit borrow. `&slice` has the type
+        // `&&[S]`, but the `index` methods takes a `&[S]`, so Rust adds an
+        // implicit dereference. We cannot currently handle a position that is
+        // both implicitly dereferenced and implicitly borrowed, so the extra
+        // type sneaks in.
+        let x = slice[0].foo(); // $ method=foo type=x:S method=index SPURIOUS: type=slice:[]
     }
 
     pub fn f() {
diff --git a/rust/ql/test/library-tests/type-inference/type-inference.expected b/rust/ql/test/library-tests/type-inference/type-inference.expected
index 35df5930a5cc..0ae35aba9171 100644
--- a/rust/ql/test/library-tests/type-inference/type-inference.expected
+++ b/rust/ql/test/library-tests/type-inference/type-inference.expected
@@ -3802,113 +3802,113 @@ inferType
 | main.rs:1863:22:1863:26 | slice |  | file://:0:0:0:0 | [] |
 | main.rs:1863:22:1863:26 | slice | &T | file://:0:0:0:0 | [] |
 | main.rs:1863:22:1863:26 | slice | &T.[T] | main.rs:1830:5:1831:13 | S |
-| main.rs:1864:13:1864:13 | x |  | main.rs:1830:5:1831:13 | S |
-| main.rs:1864:17:1864:21 | slice |  | file://:0:0:0:0 | & |
-| main.rs:1864:17:1864:21 | slice |  | file://:0:0:0:0 | [] |
-| main.rs:1864:17:1864:21 | slice | &T | file://:0:0:0:0 | [] |
-| main.rs:1864:17:1864:21 | slice | &T.[T] | main.rs:1830:5:1831:13 | S |
-| main.rs:1864:17:1864:24 | slice[0] |  | main.rs:1830:5:1831:13 | S |
-| main.rs:1864:17:1864:30 | ... .foo() |  | main.rs:1830:5:1831:13 | S |
-| main.rs:1864:23:1864:23 | 0 |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1868:13:1868:19 | mut vec |  | main.rs:1839:5:1842:5 | MyVec |
-| main.rs:1868:13:1868:19 | mut vec | T | main.rs:1830:5:1831:13 | S |
-| main.rs:1868:23:1868:34 | ...::new(...) |  | main.rs:1839:5:1842:5 | MyVec |
-| main.rs:1868:23:1868:34 | ...::new(...) | T | main.rs:1830:5:1831:13 | S |
-| main.rs:1869:9:1869:11 | vec |  | main.rs:1839:5:1842:5 | MyVec |
-| main.rs:1869:9:1869:11 | vec | T | main.rs:1830:5:1831:13 | S |
-| main.rs:1869:18:1869:18 | S |  | main.rs:1830:5:1831:13 | S |
-| main.rs:1870:9:1870:11 | vec |  | main.rs:1839:5:1842:5 | MyVec |
-| main.rs:1870:9:1870:11 | vec | T | main.rs:1830:5:1831:13 | S |
-| main.rs:1870:9:1870:14 | vec[0] |  | main.rs:1830:5:1831:13 | S |
-| main.rs:1870:9:1870:20 | ... .foo() |  | main.rs:1830:5:1831:13 | S |
-| main.rs:1870:13:1870:13 | 0 |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1870:13:1870:13 | 0 |  | {EXTERNAL LOCATION} | usize |
-| main.rs:1872:13:1872:14 | xs |  | file://:0:0:0:0 | [] |
-| main.rs:1872:13:1872:14 | xs |  | file://:0:0:0:0 | [] |
-| main.rs:1872:13:1872:14 | xs | [T;...] | main.rs:1830:5:1831:13 | S |
-| main.rs:1872:13:1872:14 | xs | [T] | main.rs:1830:5:1831:13 | S |
-| main.rs:1872:21:1872:21 | 1 |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1872:26:1872:28 | [...] |  | file://:0:0:0:0 | [] |
-| main.rs:1872:26:1872:28 | [...] |  | file://:0:0:0:0 | [] |
-| main.rs:1872:26:1872:28 | [...] | [T;...] | main.rs:1830:5:1831:13 | S |
-| main.rs:1872:26:1872:28 | [...] | [T] | main.rs:1830:5:1831:13 | S |
-| main.rs:1872:27:1872:27 | S |  | main.rs:1830:5:1831:13 | S |
-| main.rs:1873:13:1873:13 | x |  | main.rs:1830:5:1831:13 | S |
-| main.rs:1873:17:1873:18 | xs |  | file://:0:0:0:0 | [] |
-| main.rs:1873:17:1873:18 | xs |  | file://:0:0:0:0 | [] |
-| main.rs:1873:17:1873:18 | xs | [T;...] | main.rs:1830:5:1831:13 | S |
-| main.rs:1873:17:1873:18 | xs | [T] | main.rs:1830:5:1831:13 | S |
-| main.rs:1873:17:1873:21 | xs[0] |  | main.rs:1830:5:1831:13 | S |
-| main.rs:1873:17:1873:27 | ... .foo() |  | main.rs:1830:5:1831:13 | S |
-| main.rs:1873:20:1873:20 | 0 |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1875:23:1875:25 | &xs |  | file://:0:0:0:0 | & |
-| main.rs:1875:23:1875:25 | &xs | &T | file://:0:0:0:0 | [] |
-| main.rs:1875:23:1875:25 | &xs | &T | file://:0:0:0:0 | [] |
-| main.rs:1875:23:1875:25 | &xs | &T.[T;...] | main.rs:1830:5:1831:13 | S |
-| main.rs:1875:23:1875:25 | &xs | &T.[T] | main.rs:1830:5:1831:13 | S |
-| main.rs:1875:24:1875:25 | xs |  | file://:0:0:0:0 | [] |
-| main.rs:1875:24:1875:25 | xs |  | file://:0:0:0:0 | [] |
-| main.rs:1875:24:1875:25 | xs | [T;...] | main.rs:1830:5:1831:13 | S |
-| main.rs:1875:24:1875:25 | xs | [T] | main.rs:1830:5:1831:13 | S |
-| main.rs:1881:25:1881:35 | "Hello, {}" |  | {EXTERNAL LOCATION} | str |
-| main.rs:1881:25:1881:45 | ...::format(...) |  | {EXTERNAL LOCATION} | String |
-| main.rs:1881:25:1881:45 | { ... } |  | {EXTERNAL LOCATION} | String |
-| main.rs:1881:38:1881:45 | "World!" |  | {EXTERNAL LOCATION} | str |
-| main.rs:1887:19:1887:23 | SelfParam |  | file://:0:0:0:0 | & |
-| main.rs:1887:19:1887:23 | SelfParam | &T | main.rs:1886:5:1888:5 | Self [trait MyAdd] |
-| main.rs:1887:26:1887:30 | value |  | main.rs:1886:17:1886:17 | T |
-| main.rs:1892:19:1892:23 | SelfParam |  | file://:0:0:0:0 | & |
-| main.rs:1892:19:1892:23 | SelfParam | &T | {EXTERNAL LOCATION} | i64 |
-| main.rs:1892:26:1892:30 | value |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1892:46:1894:9 | { ... } |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1893:13:1893:17 | value |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1899:19:1899:23 | SelfParam |  | file://:0:0:0:0 | & |
-| main.rs:1899:19:1899:23 | SelfParam | &T | {EXTERNAL LOCATION} | i64 |
-| main.rs:1899:26:1899:30 | value |  | file://:0:0:0:0 | & |
-| main.rs:1899:26:1899:30 | value | &T | {EXTERNAL LOCATION} | i64 |
-| main.rs:1899:47:1901:9 | { ... } |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1900:13:1900:18 | * ... |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1900:14:1900:18 | value |  | file://:0:0:0:0 | & |
-| main.rs:1900:14:1900:18 | value | &T | {EXTERNAL LOCATION} | i64 |
-| main.rs:1906:19:1906:23 | SelfParam |  | file://:0:0:0:0 | & |
-| main.rs:1906:19:1906:23 | SelfParam | &T | {EXTERNAL LOCATION} | i64 |
-| main.rs:1906:26:1906:30 | value |  | {EXTERNAL LOCATION} | bool |
-| main.rs:1906:47:1912:9 | { ... } |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1906:47:1912:9 | { ... } |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1907:13:1911:13 | if value {...} else {...} |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1907:13:1911:13 | if value {...} else {...} |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1907:16:1907:20 | value |  | {EXTERNAL LOCATION} | bool |
-| main.rs:1907:22:1909:13 | { ... } |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1907:22:1909:13 | { ... } |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1908:17:1908:17 | 1 |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1908:17:1908:17 | 1 |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1909:20:1911:13 | { ... } |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1909:20:1911:13 | { ... } |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1910:17:1910:17 | 0 |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1910:17:1910:17 | 0 |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1916:13:1916:13 | x |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1916:13:1916:13 | x |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1916:22:1916:23 | 73 |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1916:22:1916:23 | 73 |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1917:9:1917:9 | x |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1917:9:1917:9 | x |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1917:9:1917:22 | x.my_add(...) |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1917:18:1917:21 | 5i64 |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1918:9:1918:9 | x |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1918:9:1918:9 | x |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1918:9:1918:23 | x.my_add(...) |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1918:18:1918:22 | &5i64 |  | file://:0:0:0:0 | & |
-| main.rs:1918:18:1918:22 | &5i64 | &T | {EXTERNAL LOCATION} | i64 |
-| main.rs:1918:19:1918:22 | 5i64 |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1919:9:1919:9 | x |  | {EXTERNAL LOCATION} | i32 |
-| main.rs:1919:9:1919:9 | x |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1919:9:1919:22 | x.my_add(...) |  | {EXTERNAL LOCATION} | i64 |
-| main.rs:1919:18:1919:21 | true |  | {EXTERNAL LOCATION} | bool |
-| main.rs:1927:5:1927:20 | ...::f(...) |  | main.rs:72:5:72:21 | Foo |
-| main.rs:1928:5:1928:60 | ...::g(...) |  | main.rs:72:5:72:21 | Foo |
-| main.rs:1928:20:1928:38 | ...::Foo {...} |  | main.rs:72:5:72:21 | Foo |
-| main.rs:1928:41:1928:59 | ...::Foo {...} |  | main.rs:72:5:72:21 | Foo |
-| main.rs:1944:5:1944:15 | ...::f(...) |  | {EXTERNAL LOCATION} | trait Future |
+| main.rs:1870:13:1870:13 | x |  | main.rs:1830:5:1831:13 | S |
+| main.rs:1870:17:1870:21 | slice |  | file://:0:0:0:0 | & |
+| main.rs:1870:17:1870:21 | slice |  | file://:0:0:0:0 | [] |
+| main.rs:1870:17:1870:21 | slice | &T | file://:0:0:0:0 | [] |
+| main.rs:1870:17:1870:21 | slice | &T.[T] | main.rs:1830:5:1831:13 | S |
+| main.rs:1870:17:1870:24 | slice[0] |  | main.rs:1830:5:1831:13 | S |
+| main.rs:1870:17:1870:30 | ... .foo() |  | main.rs:1830:5:1831:13 | S |
+| main.rs:1870:23:1870:23 | 0 |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1874:13:1874:19 | mut vec |  | main.rs:1839:5:1842:5 | MyVec |
+| main.rs:1874:13:1874:19 | mut vec | T | main.rs:1830:5:1831:13 | S |
+| main.rs:1874:23:1874:34 | ...::new(...) |  | main.rs:1839:5:1842:5 | MyVec |
+| main.rs:1874:23:1874:34 | ...::new(...) | T | main.rs:1830:5:1831:13 | S |
+| main.rs:1875:9:1875:11 | vec |  | main.rs:1839:5:1842:5 | MyVec |
+| main.rs:1875:9:1875:11 | vec | T | main.rs:1830:5:1831:13 | S |
+| main.rs:1875:18:1875:18 | S |  | main.rs:1830:5:1831:13 | S |
+| main.rs:1876:9:1876:11 | vec |  | main.rs:1839:5:1842:5 | MyVec |
+| main.rs:1876:9:1876:11 | vec | T | main.rs:1830:5:1831:13 | S |
+| main.rs:1876:9:1876:14 | vec[0] |  | main.rs:1830:5:1831:13 | S |
+| main.rs:1876:9:1876:20 | ... .foo() |  | main.rs:1830:5:1831:13 | S |
+| main.rs:1876:13:1876:13 | 0 |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1876:13:1876:13 | 0 |  | {EXTERNAL LOCATION} | usize |
+| main.rs:1878:13:1878:14 | xs |  | file://:0:0:0:0 | [] |
+| main.rs:1878:13:1878:14 | xs |  | file://:0:0:0:0 | [] |
+| main.rs:1878:13:1878:14 | xs | [T;...] | main.rs:1830:5:1831:13 | S |
+| main.rs:1878:13:1878:14 | xs | [T] | main.rs:1830:5:1831:13 | S |
+| main.rs:1878:21:1878:21 | 1 |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1878:26:1878:28 | [...] |  | file://:0:0:0:0 | [] |
+| main.rs:1878:26:1878:28 | [...] |  | file://:0:0:0:0 | [] |
+| main.rs:1878:26:1878:28 | [...] | [T;...] | main.rs:1830:5:1831:13 | S |
+| main.rs:1878:26:1878:28 | [...] | [T] | main.rs:1830:5:1831:13 | S |
+| main.rs:1878:27:1878:27 | S |  | main.rs:1830:5:1831:13 | S |
+| main.rs:1879:13:1879:13 | x |  | main.rs:1830:5:1831:13 | S |
+| main.rs:1879:17:1879:18 | xs |  | file://:0:0:0:0 | [] |
+| main.rs:1879:17:1879:18 | xs |  | file://:0:0:0:0 | [] |
+| main.rs:1879:17:1879:18 | xs | [T;...] | main.rs:1830:5:1831:13 | S |
+| main.rs:1879:17:1879:18 | xs | [T] | main.rs:1830:5:1831:13 | S |
+| main.rs:1879:17:1879:21 | xs[0] |  | main.rs:1830:5:1831:13 | S |
+| main.rs:1879:17:1879:27 | ... .foo() |  | main.rs:1830:5:1831:13 | S |
+| main.rs:1879:20:1879:20 | 0 |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1881:23:1881:25 | &xs |  | file://:0:0:0:0 | & |
+| main.rs:1881:23:1881:25 | &xs | &T | file://:0:0:0:0 | [] |
+| main.rs:1881:23:1881:25 | &xs | &T | file://:0:0:0:0 | [] |
+| main.rs:1881:23:1881:25 | &xs | &T.[T;...] | main.rs:1830:5:1831:13 | S |
+| main.rs:1881:23:1881:25 | &xs | &T.[T] | main.rs:1830:5:1831:13 | S |
+| main.rs:1881:24:1881:25 | xs |  | file://:0:0:0:0 | [] |
+| main.rs:1881:24:1881:25 | xs |  | file://:0:0:0:0 | [] |
+| main.rs:1881:24:1881:25 | xs | [T;...] | main.rs:1830:5:1831:13 | S |
+| main.rs:1881:24:1881:25 | xs | [T] | main.rs:1830:5:1831:13 | S |
+| main.rs:1887:25:1887:35 | "Hello, {}" |  | {EXTERNAL LOCATION} | str |
+| main.rs:1887:25:1887:45 | ...::format(...) |  | {EXTERNAL LOCATION} | String |
+| main.rs:1887:25:1887:45 | { ... } |  | {EXTERNAL LOCATION} | String |
+| main.rs:1887:38:1887:45 | "World!" |  | {EXTERNAL LOCATION} | str |
+| main.rs:1893:19:1893:23 | SelfParam |  | file://:0:0:0:0 | & |
+| main.rs:1893:19:1893:23 | SelfParam | &T | main.rs:1892:5:1894:5 | Self [trait MyAdd] |
+| main.rs:1893:26:1893:30 | value |  | main.rs:1892:17:1892:17 | T |
+| main.rs:1898:19:1898:23 | SelfParam |  | file://:0:0:0:0 | & |
+| main.rs:1898:19:1898:23 | SelfParam | &T | {EXTERNAL LOCATION} | i64 |
+| main.rs:1898:26:1898:30 | value |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1898:46:1900:9 | { ... } |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1899:13:1899:17 | value |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1905:19:1905:23 | SelfParam |  | file://:0:0:0:0 | & |
+| main.rs:1905:19:1905:23 | SelfParam | &T | {EXTERNAL LOCATION} | i64 |
+| main.rs:1905:26:1905:30 | value |  | file://:0:0:0:0 | & |
+| main.rs:1905:26:1905:30 | value | &T | {EXTERNAL LOCATION} | i64 |
+| main.rs:1905:47:1907:9 | { ... } |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1906:13:1906:18 | * ... |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1906:14:1906:18 | value |  | file://:0:0:0:0 | & |
+| main.rs:1906:14:1906:18 | value | &T | {EXTERNAL LOCATION} | i64 |
+| main.rs:1912:19:1912:23 | SelfParam |  | file://:0:0:0:0 | & |
+| main.rs:1912:19:1912:23 | SelfParam | &T | {EXTERNAL LOCATION} | i64 |
+| main.rs:1912:26:1912:30 | value |  | {EXTERNAL LOCATION} | bool |
+| main.rs:1912:47:1918:9 | { ... } |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1912:47:1918:9 | { ... } |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1913:13:1917:13 | if value {...} else {...} |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1913:13:1917:13 | if value {...} else {...} |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1913:16:1913:20 | value |  | {EXTERNAL LOCATION} | bool |
+| main.rs:1913:22:1915:13 | { ... } |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1913:22:1915:13 | { ... } |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1914:17:1914:17 | 1 |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1914:17:1914:17 | 1 |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1915:20:1917:13 | { ... } |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1915:20:1917:13 | { ... } |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1916:17:1916:17 | 0 |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1916:17:1916:17 | 0 |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1922:13:1922:13 | x |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1922:13:1922:13 | x |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1922:22:1922:23 | 73 |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1922:22:1922:23 | 73 |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1923:9:1923:9 | x |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1923:9:1923:9 | x |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1923:9:1923:22 | x.my_add(...) |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1923:18:1923:21 | 5i64 |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1924:9:1924:9 | x |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1924:9:1924:9 | x |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1924:9:1924:23 | x.my_add(...) |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1924:18:1924:22 | &5i64 |  | file://:0:0:0:0 | & |
+| main.rs:1924:18:1924:22 | &5i64 | &T | {EXTERNAL LOCATION} | i64 |
+| main.rs:1924:19:1924:22 | 5i64 |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1925:9:1925:9 | x |  | {EXTERNAL LOCATION} | i32 |
+| main.rs:1925:9:1925:9 | x |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1925:9:1925:22 | x.my_add(...) |  | {EXTERNAL LOCATION} | i64 |
+| main.rs:1925:18:1925:21 | true |  | {EXTERNAL LOCATION} | bool |
+| main.rs:1933:5:1933:20 | ...::f(...) |  | main.rs:72:5:72:21 | Foo |
+| main.rs:1934:5:1934:60 | ...::g(...) |  | main.rs:72:5:72:21 | Foo |
+| main.rs:1934:20:1934:38 | ...::Foo {...} |  | main.rs:72:5:72:21 | Foo |
+| main.rs:1934:41:1934:59 | ...::Foo {...} |  | main.rs:72:5:72:21 | Foo |
+| main.rs:1950:5:1950:15 | ...::f(...) |  | {EXTERNAL LOCATION} | trait Future |
 testFailures
 | main.rs:2:5:2:20 | f.write_str(...) | Unexpected result: method=write_str |
 | main.rs:5:5:5:20 | f.debug_struct(...) | Unexpected result: method=debug_struct |

From 326c7de521b116f85d51fce73c10b8e906d66050 Mon Sep 17 00:00:00 2001
From: Simon Friis Vindum <simonfv@gmail.com>
Date: Sat, 21 Jun 2025 13:16:40 +0200
Subject: [PATCH 3/4] Rust: Ensure index expressions are not handled as calls
 yet in data flow

---
 .../lib/codeql/rust/dataflow/internal/DataFlowImpl.qll | 10 +++++++---
 rust/ql/lib/codeql/rust/dataflow/internal/Node.qll     |  6 +++++-
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/rust/ql/lib/codeql/rust/dataflow/internal/DataFlowImpl.qll b/rust/ql/lib/codeql/rust/dataflow/internal/DataFlowImpl.qll
index 20c9e80b87aa..fb3a46d78663 100644
--- a/rust/ql/lib/codeql/rust/dataflow/internal/DataFlowImpl.qll
+++ b/rust/ql/lib/codeql/rust/dataflow/internal/DataFlowImpl.qll
@@ -145,9 +145,13 @@ final class ArgumentPosition extends ParameterPosition {
  * as the synthetic `ReceiverNode` is the argument for the `self` parameter.
  */
 predicate isArgumentForCall(ExprCfgNode arg, CallCfgNode call, ParameterPosition pos) {
-  call.getPositionalArgument(pos.getPosition()) = arg
-  or
-  call.getReceiver() = arg and pos.isSelf() and not call.getCall().receiverImplicitlyBorrowed()
+  // TODO: Handle index expressions as calls in data flow.
+  not call.getCall() instanceof IndexExpr and
+  (
+    call.getPositionalArgument(pos.getPosition()) = arg
+    or
+    call.getReceiver() = arg and pos.isSelf() and not call.getCall().receiverImplicitlyBorrowed()
+  )
 }
 
 /** Provides logic related to SSA. */
diff --git a/rust/ql/lib/codeql/rust/dataflow/internal/Node.qll b/rust/ql/lib/codeql/rust/dataflow/internal/Node.qll
index 51343c1eb40a..b18ccbacbd6a 100644
--- a/rust/ql/lib/codeql/rust/dataflow/internal/Node.qll
+++ b/rust/ql/lib/codeql/rust/dataflow/internal/Node.qll
@@ -472,7 +472,11 @@ newtype TNode =
         getPostUpdateReverseStep(any(PostUpdateNode n).getPreUpdateNode().asExpr(), _)
       ]
   } or
-  TReceiverNode(CallCfgNode mc, Boolean isPost) { mc.getCall().receiverImplicitlyBorrowed() } or
+  TReceiverNode(CallCfgNode mc, Boolean isPost) {
+    mc.getCall().receiverImplicitlyBorrowed() and
+    // TODO: Handle index expressions as calls in data flow.
+    not mc.getCall() instanceof IndexExpr
+  } or
   TSsaNode(SsaImpl::DataFlowIntegration::SsaNode node) or
   TFlowSummaryNode(FlowSummaryImpl::Private::SummaryNode sn) or
   TClosureSelfReferenceNode(CfgScope c) { lambdaCreationExpr(c, _) } or

From 153e91bebbf8c458c76708148441bd1facdf078b Mon Sep 17 00:00:00 2001
From: Simon Friis Vindum <simonfv@gmail.com>
Date: Tue, 24 Jun 2025 09:30:23 +0200
Subject: [PATCH 4/4] Rust: Re-enable special casing in indexing for `Vec`

---
 rust/ql/lib/codeql/rust/internal/TypeInference.qll | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/rust/ql/lib/codeql/rust/internal/TypeInference.qll b/rust/ql/lib/codeql/rust/internal/TypeInference.qll
index 04cb6b2c4840..2052f3f74d9d 100644
--- a/rust/ql/lib/codeql/rust/internal/TypeInference.qll
+++ b/rust/ql/lib/codeql/rust/internal/TypeInference.qll
@@ -1132,6 +1132,8 @@ private Type inferIndexExprType(IndexExpr ie, TypePath path) {
     ) and
     result = inferType(ie.getBase(), exprPath)
   |
+    exprPath.isCons(any(Vec v).getElementTypeParameter(), path)
+    or
     exprPath.isCons(any(ArrayTypeParameter tp), path)
     or
     exists(TypePath path0 |