Rust: Address comments

Author: paldepind

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

@@ -143,7 +143,11 @@ class NonAliasPathTypeMention extends PathTypeMention {
     )
   }
 
-  private TypeMention getPositionalTypeArgument0(int i) {
+  /**
+   * Gets the positional type argument at index `i` that occurs in this path, if
+   * any.
+   */
+  private TypeMention getPathPositionalTypeArgument(int i) {
     result = this.getSegment().getGenericArgList().getTypeArg(i)
     or
     // `Option::<i32>::Some` is valid in addition to `Option::Some::<i32>`
@@ -155,7 +159,7 @@ class NonAliasPathTypeMention extends PathTypeMention {
    * Gets the type mention that instantiates the implicit `Self` type parameter
    * for this path, if it occurs in the position of a trait bound.
    */
-  private TypeMention getSelfTypeParameter() {
+  private TypeMention getSelfTraitBoundArg() {
     exists(ImplItemNode impl | this = impl.getTraitPath() and result = impl.(Impl).getSelfTy())
     or
     exists(Trait subTrait |
@@ -166,16 +170,10 @@ class NonAliasPathTypeMention extends PathTypeMention {
     exists(TypeParamItemNode tp | this = tp.getABoundPath() and result = tp)
   }
 
-  private Type getPositionalTypeArgument(int i, TypePath path) {
-    result = this.getPositionalTypeArgument0(i).resolveTypeAt(path)
-    or
-    result = this.getDefaultPositionalTypeArgument(i, path)
-  }
-
   private Type getDefaultPositionalTypeArgument(int i, TypePath path) {
     // If a type argument is not given in the path, then we use the default for
     // the type parameter if one exists for the type.
-    not exists(this.getPositionalTypeArgument0(i)) and
+    not exists(this.getPathPositionalTypeArgument(i)) and
     // Defaults only apply to type mentions in type annotations
     this = any(PathTypeRepr ptp).getPath().getQualifier*() and
     exists(Type ty, TypePath prefix |
@@ -187,11 +185,17 @@ class NonAliasPathTypeMention extends PathTypeMention {
         // be substituted for the type that implements the trait.
         exists(TypePath suffix |
           path = prefix.append(suffix) and
-          result = this.getSelfTypeParameter().resolveTypeAt(suffix)
+          result = this.getSelfTraitBoundArg().resolveTypeAt(suffix)
         )
     )
   }
 
+  private Type getPositionalTypeArgument(int i, TypePath path) {
+    result = this.getPathPositionalTypeArgument(i).resolveTypeAt(path)
+    or
+    result = this.getDefaultPositionalTypeArgument(i, path)
+  }
+
   /**
    * Gets the type for this path for the type parameter `tp` at `path`, when the
    * type parameter does not correspond directly to a type mention.
@@ -282,7 +286,7 @@ class NonAliasPathTypeMention extends PathTypeMention {
     // When the path refers to a trait, then the implicit `Self` type parameter
     // should be instantiated from the context.
     exists(TypePath suffix |
-      result = this.getSelfTypeParameter().resolveTypeAt(suffix) and
+      result = this.getSelfTraitBoundArg().resolveTypeAt(suffix) and
       typePath = TypePath::cons(TSelfTypeParameter(resolved), suffix)
     )
   }

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

@@ -5,9 +5,9 @@ multipleCallTargets
 | dereference.rs:184:17:184:30 | ... .foo() |
 | dereference.rs:186:17:186:25 | S.bar(...) |
 | dereference.rs:187:17:187:29 | S.bar(...) |
+| main.rs:2481:13:2481:31 | ...::from(...) |
 | main.rs:2482:13:2482:31 | ...::from(...) |
 | main.rs:2483:13:2483:31 | ...::from(...) |
-| main.rs:2484:13:2484:31 | ...::from(...) |
+| main.rs:2489:13:2489:31 | ...::from(...) |
 | main.rs:2490:13:2490:31 | ...::from(...) |
 | main.rs:2491:13:2491:31 | ...::from(...) |
-| main.rs:2492:13:2492:31 | ...::from(...) |

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

@@ -654,7 +654,6 @@ mod type_parameter_bounds {
 
 mod trait_default_self_type_parameter {
     // A trait with a type parameter that defaults to `Self`.
-    // trait TraitWithSelfTp<A = Self> {
     trait TraitWithSelfTp<A = Option<Self>> {
         // TraitWithSelfTp::get_a
         fn get_a(&self) -> A;