Swift: MethodLookupExpr.getMethodRef() [hand-written]

This refactors SelfApplyExpr.getFunction() as MethodLookupExpr().getMethodRef().

This is simpler, because we are not hiding DeclRefExprs or reinventing hidden AST resolution.

Author: d10c

swift/ql/lib/codeql/swift/elements/expr/ArgumentConstructor.qll

@@ -4,5 +4,5 @@ private import codeql.swift.elements.expr.MethodLookupExpr
 predicate constructArgument(Raw::Argument id) {
   // exclude an argument that will be part of a SelfApplyExpr
   // that will be transformed into a MethodLookupExpr
-  not exists(Raw::SelfApplyExpr e | id.getExpr() = e.getBase())
+  not exists(Raw::SelfApplyExpr e | id = e.getArgument(0))
 }

swift/ql/lib/codeql/swift/elements/expr/DeclRefExprConstructor.qll

@@ -1,8 +1,4 @@
+// generated by codegen/codegen.py, remove this comment if you wish to edit this file
 private import codeql.swift.generated.Raw
-private import codeql.swift.elements.expr.MethodLookupExprConstructor
 
-predicate constructDeclRefExpr(Raw::DeclRefExpr id) {
-  // exclude an argument that will be part of a SelfApplyExpr
-  // that will be transformed into a MethodLookupExpr
-  not exists(Raw::SelfApplyExpr e | id.getDecl() = extractDeclFromSelfApplyExpr(e))
-}
+predicate constructDeclRefExpr(Raw::DeclRefExpr id) { any() }

swift/ql/lib/codeql/swift/elements/expr/MethodLookupExpr.qll

@@ -1,6 +1,8 @@
 private import codeql.swift.generated.expr.MethodLookupExpr
 private import codeql.swift.elements.expr.MethodLookupExprConstructor
 private import codeql.swift.elements.expr.Expr
+private import codeql.swift.elements.expr.DeclRefExpr
+private import codeql.swift.elements.expr.OtherConstructorDeclRefExpr
 private import codeql.swift.elements.decl.Decl
 private import codeql.swift.elements.decl.MethodDecl
 private import codeql.swift.generated.Raw
@@ -14,7 +16,13 @@ class MethodLookupExpr extends Generated::MethodLookupExpr {
   }
 
   override Decl getImmediateMember() {
-    result = Synth::convertDeclFromRaw(extractDeclFromSelfApplyExpr(this.getUnderlying()))
+    result = this.getMethodRef().(DeclRefExpr).getDecl()
+    or
+    result = this.getMethodRef().(OtherConstructorDeclRefExpr).getConstructorDecl()
+  }
+
+  override Expr getImmediateMethodRef() {
+    result = Synth::convertExprFromRaw(this.getUnderlying().getFunction())
   }
 
   MethodDecl getMethod() { result = this.getMember() }

swift/ql/lib/codeql/swift/elements/expr/MethodLookupExprConstructor.qll

@@ -1,17 +1,3 @@
 private import codeql.swift.generated.Raw
 
 predicate constructMethodLookupExpr(Raw::SelfApplyExpr id) { any() }
-
-Raw::Decl extractDeclFromSelfApplyExpr(Raw::SelfApplyExpr e) {
-  exists(Raw::Expr unwrappedFunction | unwrappedFunction = unwrapConversion*(e.getFunction()) |
-    result =
-      [
-        unwrappedFunction.(Raw::DeclRefExpr).getDecl(),
-        unwrappedFunction.(Raw::OtherConstructorDeclRefExpr).getConstructorDecl()
-      ]
-  )
-}
-
-private Raw::Expr unwrapConversion(Raw::Expr e) {
-  e.(Raw::ImplicitConversionExpr).getSubExpr() = result
-}

swift/ql/lib/codeql/swift/elements/expr/OtherConstructorDeclRefExprConstructor.qll

@@ -1,8 +1,4 @@
+// generated by codegen/codegen.py, remove this comment if you wish to edit this file
 private import codeql.swift.generated.Raw
-private import codeql.swift.elements.expr.MethodLookupExprConstructor
 
-predicate constructOtherConstructorDeclRefExpr(Raw::OtherConstructorDeclRefExpr id) {
-  // exclude an argument that will be part of a SelfApplyExpr
-  // that will be transformed into a MethodLookupExpr
-  not exists(Raw::SelfApplyExpr e | id.getConstructorDecl() = extractDeclFromSelfApplyExpr(e))
-}
+predicate constructOtherConstructorDeclRefExpr(Raw::OtherConstructorDeclRefExpr id) { any() }

swift/schema.py

@@ -677,7 +677,7 @@ class DotSyntaxCallExpr(SelfApplyExpr):
 
 @synth.from_class(SelfApplyExpr)
 class MethodLookupExpr(LookupExpr):
-    pass
+    method_ref: Expr | child | doc("the underlying method declaration reference expression")
 
 class DynamicMemberRefExpr(DynamicLookupExpr):
     pass