Unified: Move extension workaround into static name binding library

unified/ql/lib/codeql/unified/internal/AnalysisQuality.qll

@@ -53,12 +53,6 @@ module StaticNameResolutionStats implements EntityStatsSig {
         or
         result.isModuleScopeNode(_) and
         result.(NamespaceNode).ref().isIdentifier(this)
-      ) and
-      // Do not consider a type extension to be a valid target
-      // TODO: Fix in the AST mapping: type extensions should reference their type, not declare it
-      not exists(ClassLikeDeclaration cls |
-        cls.hasModifier("extension") and
-        result.isIdentifier(cls.getName())
       )
     }
 

unified/ql/lib/codeql/unified/internal/LocalNameBinding.qll

@@ -231,6 +231,7 @@ private module LocalNameBindingInput implements LocalNameBindingInputSig<Locatio
     exists(ClassLikeDeclaration cls |
       getChild(scope, _) = cls and
       pattern = cls.getName() and
+      not cls.hasModifier("extension") and // TODO: Fix in the AST mapping: type extensions should reference their type, not declare it
       declaration = cls
     )
     or
@@ -382,6 +383,8 @@ class PotentialLocalNameAccess extends Identifier {
     this = any(NamedTypeExpr e | not exists(e.getQualifier())).getName()
     or
     this instanceof NameDeclaration
+    or
+    this = any(ClassLikeDeclaration cls | cls.hasModifier("extension")).getName() // TODO: Fix in the AST mapping: type extensions should reference their type, not declare it
   }
 
   LocalName getLocalName() { result = this.(LocalNameBindingOutput::LocalAccess).getLocal() }

unified/ql/lib/codeql/unified/internal/StaticNameBinding.qll

@@ -476,7 +476,6 @@ private module FolderHeuristic {
     exists(TopLevel top, Stmt stmt, NameDeclaration nameDecl |
       top.getFile() = file and
       stmt = top.getBody().getAStmt() and
-      not stmt.(ClassLikeDeclaration).hasModifier("extension") and // TODO: target of type extensions should not be seen as a NameDeclaration
       not isPrivateToLocalScope(nameDecl) and
       nameDecl.getDeclaration() = stmt and
       name = nameDecl.getName() and

unified/ql/test/library-tests/static-name-binding/test.swift

@@ -46,7 +46,7 @@ class F {
 typealias G = A // $ access=A
 
 // Members can be accessed through aliases, but references to the alias itself do not bypass the alias.
-class H {
+class H { // name=H1
     let x1: G = nil; // $ access=G
     let x2: G.B = nil; // $ access=G access=A.B
     let x3: G.B.C = nil; // $ access=G access=A.B access=A.B.C
@@ -62,3 +62,11 @@ func useI() {
     I.two // $ access=I access=I.two
     I.three // $ access=I access=I.three
 }
+
+protocol P { }
+
+extension H // $ access=H1
+  : P { } // $ access=P
+
+extension A.B.C // $ MISSING: access=A access=A.B access=A.B.C (`A.B.C` is currently parsed as a single identifier)
+  : P { } // $ access=P