Swift: Go through protocols added in extensions also.

Author: geoffw0

swift/ql/lib/codeql/swift/elements/decl/TypeDecl.qll

@@ -35,17 +35,24 @@ class TypeDecl extends Generated::TypeDecl {
   deprecated Type getBaseType(int index) { result = this.getInheritedType(index) }
 
   /**
-   * Gets any of the base types of this type declaration. Expands type aliases, for example
-   * in the following code, `B` has base type `A`.
+   * Gets any of the base types of this type declaration. Expands protocols added in
+   * extensions and expands type aliases. For example in the following code, `B` has
+   * base type `A`:
    * ```
    * typealias A_alias = A
    *
    * class B : A_alias {}
    * ```
    */
   Type getABaseType() {
-    // TODO generalize this to consider bases added by extensions
+    // direct base type
     result = this.getAnInheritedType().getUnderlyingType()
+    or
+    // protocol added in an extension of the type
+    exists(ExtensionDecl ed |
+      ed.getExtendedTypeDecl() = this and
+      ed.getAProtocol().getType() = result
+    )
   }
 
   /**
@@ -57,8 +64,9 @@ class TypeDecl extends Generated::TypeDecl {
   }
 
   /**
-   * Gets the declaration of any of the base types of this type declaration. Expands type
-   * aliases, for example in the following code, `B` has base type decl `A`.
+   * Gets the declaration of any of the base types of this type declaration. Expands
+   * protocols added in extensions and expands type aliases. For example in the following
+   * code, `B` has base type `A`.
    * ```
    * typealias A_alias = A
    *
@@ -75,8 +83,9 @@ class TypeDecl extends Generated::TypeDecl {
   deprecated TypeDecl getDerivedTypeDecl(int i) { result.getBaseTypeDecl(i) = this }
 
   /**
-   * Gets the declaration of any type derived from this type declaration. Expands type aliases,
-   * for example in the following code, `B` is derived from `A`.
+   * Gets the declaration of any type derived from this type declaration. Expands protocols
+   * added in extensions and expands type aliases. For example in the following code, `B`
+   * is derived from `A`.
    * ```
    * typealias A_alias = A
    *

swift/ql/lib/codeql/swift/elements/type/Type.qll

@@ -43,8 +43,8 @@ class Type extends Generated::Type {
   Type getUnderlyingType() { result = this }
 
   /**
-   * Gets any base type of this type. Expands type aliases, for example in the following
-   * code, `B` has base type `A`.
+   * Gets any base type of this type. Expands protocols added in extensions and expands
+   * type aliases. For example in the following code, `B` has base type `A`:
    * ```
    * typealias A_alias = A
    *

swift/ql/test/library-tests/elements/type/nominaltype/nominaltype.expected

@@ -1,4 +1,4 @@
-| nominaltype.swift:84:6:84:6 | i | Int | getABaseType:FixedWidthInteger, getABaseType:SignedInteger, getABaseType:_ExpressibleByBuiltinIntegerLiteral, getFullName:Int, getName:Int, getUnderlyingType:Int |
+| nominaltype.swift:84:6:84:6 | i | Int | getABaseType:CVarArg, getABaseType:CodingKeyRepresentable, getABaseType:CustomReflectable, getABaseType:Decodable, getABaseType:Encodable, getABaseType:Equatable, getABaseType:FixedWidthInteger, getABaseType:Hashable, getABaseType:MirrorPath, getABaseType:SIMDScalar, getABaseType:Sendable, getABaseType:SignedInteger, getABaseType:_CustomPlaygroundQuickLookable, getABaseType:_ExpressibleByBuiltinIntegerLiteral, getABaseType:_HasCustomAnyHashableRepresentation, getFullName:Int, getName:Int, getUnderlyingType:Int |
 | nominaltype.swift:85:6:85:6 | j | Any? | getFullName:Any?, getName:Any?, getUnderlyingType:Any? |
 | nominaltype.swift:86:6:86:6 | a | A | getFullName:A, getName:A, getUnderlyingType:A |
 | nominaltype.swift:87:6:87:6 | a_alias | A_alias | getAliasedType:A, getFullName:A_alias, getName:A_alias, getUnderlyingType:A |
@@ -16,5 +16,5 @@
 | nominaltype.swift:99:6:99:6 | oia | Outer.Inner.InnerAlias | getAliasedType:A, getFullName:Outer.Inner.InnerAlias, getName:InnerAlias, getUnderlyingType:A |
 | nominaltype.swift:100:6:100:6 | p1p2 | P1P2 | getFullName:P1P2, getName:P1P2, getUnderlyingType:P1P2 |
 | nominaltype.swift:101:6:101:6 | boxInt | Box<A> | getFullName:Box<A>, getName:Box<A>, getUnderlyingType:Box<A> |
-| nominaltype.swift:102:6:102:6 | d1 | D1 | getFullName:D1, getName:D1, getUnderlyingType:D1 |
-| nominaltype.swift:103:6:103:6 | d2 | D2 | getFullName:D2, getName:D2, getUnderlyingType:D2 |
+| nominaltype.swift:102:6:102:6 | d1 | D1 | getABaseType:P3, getFullName:D1, getName:D1, getUnderlyingType:D1 |
+| nominaltype.swift:103:6:103:6 | d2 | D2 | getABaseType:P4, getFullName:D2, getName:D2, getUnderlyingType:D2 |

swift/ql/test/library-tests/elements/type/nominaltype/nominaltypedecl.expected

@@ -1,4 +1,4 @@
-| nominaltype.swift:84:6:84:6 | i | Int | getABaseType:FixedWidthInteger, getABaseType:SignedInteger, getABaseType:_ExpressibleByBuiltinIntegerLiteral, getABaseTypeDecl:FixedWidthInteger, getABaseTypeDecl:SignedInteger, getABaseTypeDecl:_ExpressibleByBuiltinIntegerLiteral, getFullName:Int, getName:Int |
+| nominaltype.swift:84:6:84:6 | i | Int | getABaseType:CVarArg, getABaseType:CodingKeyRepresentable, getABaseType:CustomReflectable, getABaseType:Decodable, getABaseType:Encodable, getABaseType:Equatable, getABaseType:FixedWidthInteger, getABaseType:Hashable, getABaseType:MirrorPath, getABaseType:SIMDScalar, getABaseType:Sendable, getABaseType:SignedInteger, getABaseType:_CustomPlaygroundQuickLookable, getABaseType:_ExpressibleByBuiltinIntegerLiteral, getABaseType:_HasCustomAnyHashableRepresentation, getABaseTypeDecl:CVarArg, getABaseTypeDecl:CodingKeyRepresentable, getABaseTypeDecl:CustomReflectable, getABaseTypeDecl:Decodable, getABaseTypeDecl:Encodable, getABaseTypeDecl:Equatable, getABaseTypeDecl:FixedWidthInteger, getABaseTypeDecl:Hashable, getABaseTypeDecl:MirrorPath, getABaseTypeDecl:SIMDScalar, getABaseTypeDecl:Sendable, getABaseTypeDecl:SignedInteger, getABaseTypeDecl:_CustomPlaygroundQuickLookable, getABaseTypeDecl:_ExpressibleByBuiltinIntegerLiteral, getABaseTypeDecl:_HasCustomAnyHashableRepresentation, getFullName:Int, getName:Int |
 | nominaltype.swift:86:6:86:6 | a | A | getFullName:A, getName:A |
 | nominaltype.swift:87:6:87:6 | a_alias | A_alias | getAliasedType:A, getFullName:A_alias, getName:A_alias |
 | nominaltype.swift:88:6:88:6 | a_optional_alias | A_optional_alias | getAliasedType:A?, getFullName:A_optional_alias, getName:A_optional_alias |
@@ -11,5 +11,5 @@
 | nominaltype.swift:97:6:97:6 | o | Outer | getFullName:Outer, getName:Outer |
 | nominaltype.swift:98:6:98:6 | oi | Inner | getFullName:Outer.Inner, getName:Inner |
 | nominaltype.swift:99:6:99:6 | oia | InnerAlias | getAliasedType:A, getFullName:Outer.Inner.InnerAlias, getName:InnerAlias |
-| nominaltype.swift:102:6:102:6 | d1 | D1 | getFullName:D1, getName:D1 |
-| nominaltype.swift:103:6:103:6 | d2 | D2 | getFullName:D2, getName:D2 |
+| nominaltype.swift:102:6:102:6 | d1 | D1 | getABaseType:P3, getABaseTypeDecl:P3, getFullName:D1, getName:D1 |
+| nominaltype.swift:103:6:103:6 | d2 | D2 | getABaseType:P4, getABaseTypeDecl:P4, getFullName:D2, getName:D2 |