Swift: sources in extension protocols.

Author: geoffw0

swift/ql/lib/codeql/swift/dataflow/ExternalFlow.qll

@@ -434,6 +434,11 @@ private Element interpretElement0(
       subtypes = true and
       decl.getNominalTypeDecl() = nomTypeDecl.getADerivedTypeDecl*()
       or
+      exists(ExtensionDecl e | e.getExtendedTypeDecl() = decl.getNominalTypeDecl() |
+        subtypes = true and
+        e.getAProtocol() = nomTypeDecl.getADerivedTypeDecl*()
+      )
+      or
       subtypes = false and
       decl.getNominalTypeDecl() = nomTypeDecl
     )
@@ -449,6 +454,11 @@ private Element interpretElement0(
       subtypes = true and
       decl.getNominalTypeDecl() = nomTypeDecl.getADerivedTypeDecl*()
       or
+      exists(ExtensionDecl e | e.getExtendedTypeDecl() = decl.getNominalTypeDecl() |
+        subtypes = true and
+        e.getAProtocol() = nomTypeDecl.getADerivedTypeDecl*()
+      )
+      or
       subtypes = false and
       decl.getNominalTypeDecl() = nomTypeDecl
     )

swift/ql/test/library-tests/dataflow/flowsources/FlowSources.expected

@@ -63,6 +63,10 @@
 | generics.swift:93:9:93:15 | .source2 | external |
 | generics.swift:112:9:112:15 | .source1 | external |
 | generics.swift:113:9:113:15 | .source2 | external |
+| generics.swift:114:9:114:14 | .source1 | external |
+| generics.swift:115:9:115:14 | .source2 | external |
+| generics.swift:116:9:116:15 | .source1 | external |
+| generics.swift:117:9:117:15 | .source2 | external |
 | nsdata.swift:18:17:18:40 | call to NSData.init(contentsOf:) | external |
 | nsdata.swift:19:17:19:53 | call to NSData.init(contentsOf:options:) | external |
 | string.swift:56:21:56:44 | call to String.init(contentsOf:) | external |

swift/ql/test/library-tests/dataflow/flowsources/generics.swift

@@ -111,8 +111,8 @@ extension MyImpl2 : MyProtocol2 {
 func useProtocol2(proto: MyProtocol2, impl: MyImpl2<Int>, impl2: MyImpl2<Any>) {
     _ = proto.source1 // SOURCE
     _ = proto.source2 // SOURCE
-    _ = impl.source1 // SOURCE [NOT DETECTED]
-    _ = impl.source2 // SOURCE [NOT DETECTED]
-    _ = impl2.source1 // SOURCE [NOT DETECTED]
-    _ = impl2.source2 // SOURCE [NOT DETECTED]
+    _ = impl.source1 // SOURCE
+    _ = impl.source2 // SOURCE
+    _ = impl2.source1 // SOURCE
+    _ = impl2.source2 // SOURCE
 }