wip

Author: hvitved

rust/ql/lib/codeql/rust/internal/TypeInference.qll

@@ -2593,21 +2593,32 @@ private Type inferMethodCallTypeSelf(
     apos.isSelf()
   )
   or
+  // adjust for implicit borrow
   exists(TypePath path0, BorrowKind borrow0 |
     result = inferMethodCallTypeSelf(n, derefChain, borrow0, path0) and
-    // adjust for implicit borrow
     path0.isCons(borrow0.getRefType().getPositionalTypeParameter(0), path) and
     borrow.isNoBorrow()
   )
   or
-  exists(TypePath path0 |
-    result = inferMethodCallTypeSelf(n, derefChain, borrow, path0) and
+  // adjust for implicit deref
+  exists(
+    DerefChain derefChain0, Type t0, TypePath path0, DerefImplItemNode impl, Type selfType,
+    TypePath selfPath
+  |
+    t0 = inferMethodCallTypeSelf(n, derefChain0, borrow, path0) and
+    derefChain0.isCons(impl, derefChain) and
     borrow.isNoBorrow() and
-    // adjust for implicit deref
-    exists(DerefImplItemNode impl |
-      impl.isRefImpl() and
-      derefChain = DerefChain::singleton(impl) and
-      path = TypePath::cons(getRefTypeParameter(), path0)
+    selfType = impl.resolveSelfParamTypeStrippedAt(selfPath)
+  |
+    result = selfType and
+    path = selfPath and
+    not result instanceof TypeParameter
+    or
+    exists(TypeParameter tp, TypePath pathToTypeParam, TypePath suffix |
+      impl.returnTypeStrippedMentionsTypeParameterAt(tp, pathToTypeParam) and
+      path0 = pathToTypeParam.appendInverse(suffix) and
+      result = t0 and
+      path = selfPath.append(suffix)
     )
   )
 }

rust/ql/lib/codeql/rust/internal/typeinference/DerefChain.qll

@@ -2,6 +2,9 @@
 
 private import rust
 private import codeql.rust.internal.PathResolution
+private import codeql.rust.internal.Type
+private import codeql.rust.internal.TypeInference
+private import codeql.rust.internal.TypeMention
 private import codeql.rust.elements.internal.generated.Raw
 private import codeql.rust.elements.internal.generated.Synth
 private import codeql.rust.frameworks.stdlib.Stdlib
@@ -27,6 +30,35 @@ class DerefImplItemNode extends ImplItemNode {
    */
   predicate isRefImpl() { this.resolveSelfTyBuiltin() instanceof Builtins::RefType }
 
+  /** Gets the `deref` function in this `Deref` impl block. */
+  Function getDerefFunction() { result = this.getAssocItem("deref") }
+
+  private SelfParam getSelfParam() { result = this.getDerefFunction().getSelfParam() }
+
+  /**
+   * Resolves the type of of the `self` parameter inside the `deref` function,
+   * stripped of the leading `&`.
+   */
+  pragma[nomagic]
+  Type resolveSelfParamTypeStrippedAt(TypePath path) {
+    exists(TypePath path0 |
+      result = getSelfParamTypeMention(this.getSelfParam()).resolveTypeAt(path0) and
+      path0.isCons(getRefSharedTypeParameter(), path)
+    )
+  }
+
+  /**
+   * Holds if the return type of the `deref` function, stripped of the leading `&`,
+   * mentions type parameter `tp` at `path`.
+   */
+  pragma[nomagic]
+  predicate returnTypeStrippedMentionsTypeParameterAt(TypeParameter tp, TypePath path) {
+    exists(TypePath path0 |
+      tp = getReturnTypeMention(this.getDerefFunction()).resolveTypeAt(path0) and
+      path0.isCons(getRefSharedTypeParameter(), path)
+    )
+  }
+
   /** Gets an internal unique ID used to identify this block amongst all `Deref` impl blocks. */
   int getId() { idOfRaw(Synth::convertAstNodeToRaw(this), result) }
 }

rust/ql/test/library-tests/type-inference/dereference.rs

@@ -111,7 +111,7 @@ fn implicit_dereference() {
     let z = MySmartPointer { value: S(0i64) };
     let z_ = z.foo(); // $ target=foo type=z_:TRef.i64
 
-    let v = Vec::new(); // $ target=new $ MISSING: type=v:T.i32
+    let v = Vec::new(); // $ target=new type=v:T.i32
     let mut x = MySmartPointer { value: v };
     x.push(0); // $ target=push
 }

rust/ql/test/library-tests/type-inference/type-inference.expected

@@ -5285,19 +5285,25 @@ inferType
 | dereference.rs:112:14:112:20 | z.foo() | TRef | {EXTERNAL LOCATION} | i64 |
 | dereference.rs:114:9:114:9 | v |  | {EXTERNAL LOCATION} | Vec |
 | dereference.rs:114:9:114:9 | v | A | {EXTERNAL LOCATION} | Global |
+| dereference.rs:114:9:114:9 | v | T | {EXTERNAL LOCATION} | i32 |
 | dereference.rs:114:13:114:22 | ...::new(...) |  | {EXTERNAL LOCATION} | Vec |
 | dereference.rs:114:13:114:22 | ...::new(...) | A | {EXTERNAL LOCATION} | Global |
+| dereference.rs:114:13:114:22 | ...::new(...) | T | {EXTERNAL LOCATION} | i32 |
 | dereference.rs:115:13:115:13 | x |  | dereference.rs:18:1:20:1 | MySmartPointer |
 | dereference.rs:115:13:115:13 | x | T | {EXTERNAL LOCATION} | Vec |
 | dereference.rs:115:13:115:13 | x | T.A | {EXTERNAL LOCATION} | Global |
+| dereference.rs:115:13:115:13 | x | T.T | {EXTERNAL LOCATION} | i32 |
 | dereference.rs:115:17:115:43 | MySmartPointer {...} |  | dereference.rs:18:1:20:1 | MySmartPointer |
 | dereference.rs:115:17:115:43 | MySmartPointer {...} | T | {EXTERNAL LOCATION} | Vec |
 | dereference.rs:115:17:115:43 | MySmartPointer {...} | T.A | {EXTERNAL LOCATION} | Global |
+| dereference.rs:115:17:115:43 | MySmartPointer {...} | T.T | {EXTERNAL LOCATION} | i32 |
 | dereference.rs:115:41:115:41 | v |  | {EXTERNAL LOCATION} | Vec |
 | dereference.rs:115:41:115:41 | v | A | {EXTERNAL LOCATION} | Global |
+| dereference.rs:115:41:115:41 | v | T | {EXTERNAL LOCATION} | i32 |
 | dereference.rs:116:5:116:5 | x |  | dereference.rs:18:1:20:1 | MySmartPointer |
 | dereference.rs:116:5:116:5 | x | T | {EXTERNAL LOCATION} | Vec |
 | dereference.rs:116:5:116:5 | x | T.A | {EXTERNAL LOCATION} | Global |
+| dereference.rs:116:5:116:5 | x | T.T | {EXTERNAL LOCATION} | i32 |
 | dereference.rs:116:5:116:13 | x.push(...) |  | {EXTERNAL LOCATION} | () |
 | dereference.rs:116:12:116:12 | 0 |  | {EXTERNAL LOCATION} | i32 |
 | dereference.rs:143:19:151:5 | { ... } |  | {EXTERNAL LOCATION} | () |