Rust: Unify type inference logic for associated functions

Author: hvitved

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

@@ -33,5 +33,11 @@ module Impl {
         result = "impl " + trait + this.getSelfTy().toAbbreviatedString() + " { ... }"
       )
     }
+
+    /**
+     * Holds if this is an inherent `impl` block, that is, one that does not implement a trait.
+     */
+    pragma[nomagic]
+    predicate isInherent() { not this.hasTrait() }
   }
 }

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

@@ -41,16 +41,19 @@ private predicate hasFirstNonTrivialTraitBound(TypeParamItemNode tp, Trait trait
  */
 pragma[nomagic]
 predicate isBlanketLike(ImplItemNode i, TypePath blanketSelfPath, TypeParam blanketTypeParam) {
-  blanketTypeParam = i.getBlanketImplementationTypeParam() and
-  blanketSelfPath.isEmpty()
-  or
-  exists(TypeMention tm, Type root, TypeParameter tp |
-    tm = i.(Impl).getSelfTy() and
-    complexSelfRoot(root, tp) and
-    tm.getType() = root and
-    tm.getTypeAt(blanketSelfPath) = TTypeParamTypeParameter(blanketTypeParam) and
-    blanketSelfPath = TypePath::singleton(tp) and
-    hasFirstNonTrivialTraitBound(blanketTypeParam, _)
+  i.(Impl).hasTrait() and
+  (
+    blanketTypeParam = i.getBlanketImplementationTypeParam() and
+    blanketSelfPath.isEmpty()
+    or
+    exists(TypeMention tm, Type root, TypeParameter tp |
+      tm = i.(Impl).getSelfTy() and
+      complexSelfRoot(root, tp) and
+      tm.getType() = root and
+      tm.getTypeAt(blanketSelfPath) = TTypeParamTypeParameter(blanketTypeParam) and
+      blanketSelfPath = TypePath::singleton(tp) and
+      hasFirstNonTrivialTraitBound(blanketTypeParam, _)
+    )
   )
 }
 

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

@@ -29,18 +29,20 @@ class FunctionPosition extends TFunctionPosition {
 
   predicate isReturn() { this = TReturnFunctionPosition() }
 
+  /** Gets the corresponding position when function call syntax is used. */
+  FunctionPosition getFunctionCallAdjusted() {
+    (this.isReturn() or this.isTypeQualifier()) and
+    result = this
+    or
+    this.isSelf() and result.asPosition() = 0
+    or
+    result.asPosition() = this.asPosition() + 1
+  }
+
   /** Gets the corresponding position when `f` is invoked via a function call. */
   bindingset[f]
   FunctionPosition getFunctionCallAdjusted(Function f) {
-    this.isReturn() and
-    result = this
-    or
-    if f.hasSelfParam()
-    then
-      this.isSelf() and result.asPosition() = 0
-      or
-      result.asPosition() = this.asPosition() + 1
-    else result = this
+    if f.hasSelfParam() then result = this.getFunctionCallAdjusted() else result = this
   }
 
   TypeMention getTypeMention(Function f) {
@@ -197,7 +199,7 @@ class AssocFunctionType extends MkAssocFunctionType {
     exists(Function f, ImplOrTraitItemNode i, FunctionPosition pos | this.appliesTo(f, i, pos) |
       result = pos.getTypeMention(f)
       or
-      pos.isSelf() and
+      pos.isSelfOrTypeQualifier() and
       not f.hasSelfParam() and
       result = [i.(Impl).getSelfTy().(AstNode), i.(Trait).getName()]
     )
@@ -209,7 +211,7 @@ class AssocFunctionType extends MkAssocFunctionType {
 }
 
 pragma[nomagic]
-private Trait getALookupTrait(Type t) {
+Trait getALookupTrait(Type t) {
   result = t.(TypeParamTypeParameter).getTypeParam().(TypeParamItemNode).resolveABound()
   or
   result = t.(SelfTypeParameter).getTrait()