Merge pull request #19372 from paldepind/rust-ti-implementing-type-method

Rust: Support non-universal `impl` blocks

Author: paldepind

rust/ql/lib/codeql/rust/elements/internal/MethodCallExprImpl.qll

@@ -14,7 +14,13 @@ private import codeql.rust.internal.TypeInference
  * be referenced directly.
  */
 module Impl {
-  private predicate isImplFunction(Function f) { f = any(ImplItemNode impl).getAnAssocItem() }
+  private predicate isInherentImplFunction(Function f) {
+    f = any(Impl impl | not impl.hasTrait()).(ImplItemNode).getAnAssocItem()
+  }
+
+  private predicate isTraitImplFunction(Function f) {
+    f = any(Impl impl | impl.hasTrait()).(ImplItemNode).getAnAssocItem()
+  }
 
   // the following QLdoc is generated: if you need to edit it, do it in the schema file
   /**
@@ -25,23 +31,39 @@ module Impl {
    * ```
    */
   class MethodCallExpr extends Generated::MethodCallExpr {
-    override Function getStaticTarget() {
+    private Function getStaticTargetFrom(boolean fromSource) {
       result = resolveMethodCallExpr(this) and
+      (if result.fromSource() then fromSource = true else fromSource = false) and
       (
-        // prioritize `impl` methods first
-        isImplFunction(result)
+        // prioritize inherent implementation methods first
+        isInherentImplFunction(result)
         or
-        not isImplFunction(resolveMethodCallExpr(this)) and
+        not isInherentImplFunction(resolveMethodCallExpr(this)) and
         (
-          // then trait methods with default implementations
-          result.hasBody()
+          // then trait implementation methods
+          isTraitImplFunction(result)
           or
-          // and finally trait methods without default implementations
-          not resolveMethodCallExpr(this).hasBody()
+          not isTraitImplFunction(resolveMethodCallExpr(this)) and
+          (
+            // then trait methods with default implementations
+            result.hasBody()
+            or
+            // and finally trait methods without default implementations
+            not resolveMethodCallExpr(this).hasBody()
+          )
         )
       )
     }
 
+    override Function getStaticTarget() {
+      // Functions in source code also gets extracted as library code, due to
+      // this duplication we prioritize functions from source code.
+      result = this.getStaticTargetFrom(true)
+      or
+      not exists(this.getStaticTargetFrom(true)) and
+      result = this.getStaticTargetFrom(false)
+    }
+
     private string toStringPart(int index) {
       index = 0 and
       result = this.getReceiver().toAbbreviatedString()

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

@@ -446,61 +446,6 @@ class ImplItemNode extends ImplOrTraitItemNode instanceof Impl {
 
   TraitItemNode resolveTraitTy() { result = resolvePathFull(this.getTraitPath()) }
 
-  pragma[nomagic]
-  private TypeRepr getASelfTyArg() {
-    result =
-      this.getSelfPath().getSegment().getGenericArgList().getAGenericArg().(TypeArg).getTypeRepr()
-  }
-
-  /**
-   * Holds if this `impl` block is not fully parametric. That is, the implementing
-   * type is generic and the implementation is not parametrically polymorphic in all
-   * the implementing type's arguments.
-   *
-   * Examples:
-   *
-   * ```rust
-   * impl Foo { ... } // fully parametric
-   *
-   * impl<T> Foo<T> { ... } // fully parametric
-   *
-   * impl Foo<i64> { ... } // not fully parametric
-   *
-   * impl<T> Foo<Foo<T>> { ... } // not fully parametric
-   *
-   * impl<T: Trait> Foo<T> { ... } // not fully parametric
-   *
-   * impl<T> Foo<T> where T: Trait { ... } // not fully parametric
-   * ```
-   */
-  pragma[nomagic]
-  predicate isNotFullyParametric() {
-    exists(TypeRepr arg | arg = this.getASelfTyArg() |
-      not exists(resolveTypeParamPathTypeRepr(arg))
-      or
-      resolveTypeParamPathTypeRepr(arg).hasTraitBound()
-    )
-  }
-
-  /**
-   * Holds if this `impl` block is fully parametric. Examples:
-   *
-   * ```rust
-   * impl Foo { ... } // fully parametric
-   *
-   * impl<T> Foo<T> { ... } // fully parametric
-   *
-   * impl Foo<i64> { ... } // not fully parametric
-   *
-   * impl<T> Foo<Foo<T>> { ... } // not fully parametric
-   *
-   * impl<T: Trait> Foo<T> { ... } // not fully parametric
-   *
-   * impl<T> Foo<T> where T: Trait { ... } // not fully parametric
-   * ```
-   */
-  predicate isFullyParametric() { not this.isNotFullyParametric() }
-
   override AssocItemNode getAnAssocItem() { result = super.getAssocItemList().getAnAssocItem() }
 
   override string getName() { result = "(impl)" }

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

@@ -27,10 +27,6 @@ newtype TType =
  * types, such as traits and implementation blocks.
  */
 abstract class Type extends TType {
-  /** Gets the method `name` belonging to this type, if any. */
-  pragma[nomagic]
-  abstract Function getMethod(string name);
-
   /** Gets the struct field `name` belonging to this type, if any. */
   pragma[nomagic]
   abstract StructField getStructField(string name);
@@ -45,25 +41,6 @@ abstract class Type extends TType {
   /** Gets a type parameter of this type. */
   final TypeParameter getATypeParameter() { result = this.getTypeParameter(_) }
 
-  /**
-   * Gets an AST node that mentions a base type of this type, if any.
-   *
-   * Although Rust doesn't have traditional OOP-style inheritance, we model trait
-   * bounds and `impl` blocks as base types. Example:
-   *
-   * ```rust
-   * trait T1 {}
-   *
-   * trait T2 {}
-   *
-   * trait T3 : T1, T2 {}
-   * //    ^^ `this`
-   * //         ^^ `result`
-   * //             ^^ `result`
-   * ```
-   */
-  abstract TypeMention getABaseTypeMention();
-
   /** Gets a textual representation of this type. */
   abstract string toString();
 
@@ -73,21 +50,6 @@ abstract class Type extends TType {
 
 abstract private class StructOrEnumType extends Type {
   abstract ItemNode asItemNode();
-
-  final override Function getMethod(string name) {
-    result = this.asItemNode().getASuccessor(name) and
-    exists(ImplOrTraitItemNode impl | result = impl.getAnAssocItem() |
-      impl instanceof Trait
-      or
-      impl.(ImplItemNode).isFullyParametric()
-    )
-  }
-
-  /** Gets all of the fully parametric `impl` blocks that target this type. */
-  final override ImplMention getABaseTypeMention() {
-    this.asItemNode() = result.resolveSelfTy() and
-    result.isFullyParametric()
-  }
 }
 
 /** A struct type. */
@@ -138,8 +100,6 @@ class TraitType extends Type, TTrait {
 
   TraitType() { this = TTrait(trait) }
 
-  override Function getMethod(string name) { result = trait.(ItemNode).getASuccessor(name) }
-
   override StructField getStructField(string name) { none() }
 
   override TupleField getTupleField(int i) { none() }
@@ -151,14 +111,6 @@ class TraitType extends Type, TTrait {
       any(AssociatedTypeTypeParameter param | param.getTrait() = trait and param.getIndex() = i)
   }
 
-  pragma[nomagic]
-  private TypeReprMention getABoundMention() {
-    result = trait.getTypeBoundList().getABound().getTypeRepr()
-  }
-
-  /** Gets any of the trait bounds of this trait. */
-  override TypeMention getABaseTypeMention() { result = this.getABoundMention() }
-
   override string toString() { result = trait.toString() }
 
   override Location getLocation() { result = trait.getLocation() }
@@ -220,8 +172,6 @@ class ImplType extends Type, TImpl {
 
   ImplType() { this = TImpl(impl) }
 
-  override Function getMethod(string name) { result = impl.(ItemNode).getASuccessor(name) }
-
   override StructField getStructField(string name) { none() }
 
   override TupleField getTupleField(int i) { none() }
@@ -230,9 +180,6 @@ class ImplType extends Type, TImpl {
     result = TTypeParamTypeParameter(impl.getGenericParamList().getTypeParam(i))
   }
 
-  /** Get the trait implemented by this `impl` block, if any. */
-  override TypeMention getABaseTypeMention() { result = impl.getTrait() }
-
   override string toString() { result = impl.toString() }
 
   override Location getLocation() { result = impl.getLocation() }
@@ -247,8 +194,6 @@ class ImplType extends Type, TImpl {
 class ArrayType extends Type, TArrayType {
   ArrayType() { this = TArrayType() }
 
-  override Function getMethod(string name) { none() }
-
   override StructField getStructField(string name) { none() }
 
   override TupleField getTupleField(int i) { none() }
@@ -257,8 +202,6 @@ class ArrayType extends Type, TArrayType {
     none() // todo
   }
 
-  override TypeMention getABaseTypeMention() { none() }
-
   override string toString() { result = "[]" }
 
   override Location getLocation() { result instanceof EmptyLocation }
@@ -273,8 +216,6 @@ class ArrayType extends Type, TArrayType {
 class RefType extends Type, TRefType {
   RefType() { this = TRefType() }
 
-  override Function getMethod(string name) { none() }
-
   override StructField getStructField(string name) { none() }
 
   override TupleField getTupleField(int i) { none() }
@@ -284,17 +225,13 @@ class RefType extends Type, TRefType {
     i = 0
   }
 
-  override TypeMention getABaseTypeMention() { none() }
-
   override string toString() { result = "&" }
 
   override Location getLocation() { result instanceof EmptyLocation }
 }
 
 /** A type parameter. */
 abstract class TypeParameter extends Type {
-  override TypeMention getABaseTypeMention() { none() }
-
   override StructField getStructField(string name) { none() }
 
   override TupleField getTupleField(int i) { none() }
@@ -318,19 +255,9 @@ class TypeParamTypeParameter extends TypeParameter, TTypeParamTypeParameter {
 
   TypeParam getTypeParam() { result = typeParam }
 
-  override Function getMethod(string name) {
-    // NOTE: If the type parameter has trait bounds, then this finds methods
-    // on the bounding traits.
-    result = typeParam.(ItemNode).getASuccessor(name)
-  }
-
   override string toString() { result = typeParam.toString() }
 
   override Location getLocation() { result = typeParam.getLocation() }
-
-  final override TypeMention getABaseTypeMention() {
-    result = typeParam.getTypeBoundList().getABound().getTypeRepr()
-  }
 }
 
 /**
@@ -377,19 +304,13 @@ class AssociatedTypeTypeParameter extends TypeParameter, TAssociatedTypeTypePara
 
   int getIndex() { traitAliasIndex(_, result, typeAlias) }
 
-  override Function getMethod(string name) { none() }
-
   override string toString() { result = typeAlias.getName().getText() }
 
   override Location getLocation() { result = typeAlias.getLocation() }
-
-  override TypeMention getABaseTypeMention() { none() }
 }
 
 /** An implicit reference type parameter. */
 class RefTypeParameter extends TypeParameter, TRefTypeParameter {
-  override Function getMethod(string name) { none() }
-
   override string toString() { result = "&T" }
 
   override Location getLocation() { result instanceof EmptyLocation }
@@ -409,15 +330,43 @@ class SelfTypeParameter extends TypeParameter, TSelfTypeParameter {
 
   Trait getTrait() { result = trait }
 
-  override TypeMention getABaseTypeMention() { result = trait }
+  override string toString() { result = "Self [" + trait.toString() + "]" }
+
+  override Location getLocation() { result = trait.getLocation() }
+}
 
-  override Function getMethod(string name) {
-    // The `Self` type parameter is an implementation of the trait, so it has
-    // all the trait's methods.
-    result = trait.(ItemNode).getASuccessor(name)
+/**
+ * A type abstraction. I.e., a place in the program where type variables are
+ * introduced.
+ *
+ * Example:
+ * ```rust
+ * impl<A, B> Foo<A, B> { }
+ * //  ^^^^^^ a type abstraction
+ * ```
+ */
+abstract class TypeAbstraction extends AstNode {
+  abstract TypeParameter getATypeParameter();
+}
+
+final class ImplTypeAbstraction extends TypeAbstraction, Impl {
+  override TypeParamTypeParameter getATypeParameter() {
+    result.getTypeParam() = this.getGenericParamList().getATypeParam()
   }
+}
 
-  override string toString() { result = "Self [" + trait.toString() + "]" }
+final class TraitTypeAbstraction extends TypeAbstraction, Trait {
+  override TypeParamTypeParameter getATypeParameter() {
+    result.getTypeParam() = this.getGenericParamList().getATypeParam()
+  }
+}
 
-  override Location getLocation() { result = trait.getLocation() }
+final class TypeBoundTypeAbstraction extends TypeAbstraction, TypeBound {
+  override TypeParamTypeParameter getATypeParameter() { none() }
+}
+
+final class SelfTypeBoundTypeAbstraction extends TypeAbstraction, Name {
+  SelfTypeBoundTypeAbstraction() { any(Trait trait).getName() = this }
+
+  override TypeParamTypeParameter getATypeParameter() { none() }
 }