Rust: Cleanup of raw pointer types based in PR feedback

Author: paldepind

rust/ql/lib/codeql/rust/frameworks/stdlib/Builtins.qll

@@ -177,17 +177,19 @@ class RefMutType extends BuiltinType {
 }
 
 /** A builtin raw pointer type `*const T` or `*mut T`. */
-abstract class PtrType extends BuiltinType { }
+abstract private class PtrTypeImpl extends BuiltinType { }
+
+final class PtrType = PtrTypeImpl;
 
 /** The builtin raw pointer type `*const T`. */
-class PtrConstType extends PtrType {
+class PtrConstType extends PtrTypeImpl {
   PtrConstType() { this.getName() = "PtrConst" }
 
   override string getDisplayName() { result = "*const" }
 }
 
 /** The builtin raw pointer type `*mut T`. */
-class PtrMutType extends PtrType {
+class PtrMutType extends PtrTypeImpl {
   PtrMutType() { this.getName() = "PtrMut" }
 
   override string getDisplayName() { result = "*mut" }

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

@@ -339,9 +339,7 @@ class NeverType extends Type, TNeverType {
   override Location getLocation() { result instanceof EmptyLocation }
 }
 
-abstract class PtrType extends StructType {
-  override Location getLocation() { result instanceof EmptyLocation }
-}
+abstract class PtrType extends StructType { }
 
 pragma[nomagic]
 TypeParamTypeParameter getPtrTypeParameter() {

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

@@ -609,12 +609,12 @@ private predicate typeEquality(AstNode n1, TypePath prefix1, AstNode n2, TypePat
     strictcount(Expr e | bodyReturns(n1, e)) = 1
   )
   or
-  exists(RefExpr re |
-    n2 = re and
-    n1 = re.getExpr() and
-    prefix1.isEmpty() and
-    prefix2 = TypePath::singleton(inferRefExprType(re).getPositionalTypeParameter(0))
-  )
+  n2 =
+    any(RefExpr re |
+      n1 = re.getExpr() and
+      prefix1.isEmpty() and
+      prefix2 = TypePath::singleton(inferRefExprType(re).getPositionalTypeParameter(0))
+    )
   or
   n1 = n2.(RefPat).getPat() and
   prefix1.isEmpty() and
@@ -3162,6 +3162,12 @@ private Type inferIndexExprType(IndexExpr ie, TypePath path) {
   )
 }
 
+pragma[nomagic]
+private Type getInferredDerefType(DerefExpr de, TypePath path) { result = inferType(de, path) }
+
+pragma[nomagic]
+private PtrType getInferredDerefExprPtrType(DerefExpr de) { result = inferType(de.getExpr()) }
+
 /**
  * Gets the inferred type of `n` at `path` when `n` occurs in a dereference
  * expression `*n` and when `n` is known to have a raw pointer type.
@@ -3171,8 +3177,8 @@ private Type inferIndexExprType(IndexExpr ie, TypePath path) {
 private Type inferDereferencedExprPtrType(AstNode n, TypePath path) {
   exists(DerefExpr de, PtrType type, TypePath suffix |
     de.getExpr() = n and
-    type = inferType(de.getExpr()) and
-    result = inferType(de, suffix) and
+    type = getInferredDerefExprPtrType(de) and
+    result = getInferredDerefType(de, suffix) and
     path = TypePath::cons(type.getPositionalTypeParameter(0), suffix)
   )
 }