More synthesis refactoring

- Join `TElementReferenceSynth` and `TMethodCallSynth`. - Move arity and setter information into `MethodCallKind`. - Add `Synthesis::methodCall` for specifying which method calls need synthesis.
2026-04-23 07:45:17 +02:00 · 2021-05-31 15:14:42 +02:00
parent e8841e6482
commit 3ffef634d7
8 changed files with 144 additions and 204 deletions
--- a/ql/src/codeql_ruby/ast/Call.qll
+++ b/ql/src/codeql_ruby/ast/Call.qll
@@ -82,7 +82,7 @@ class MethodCall extends Call, TMethodCall {
   *
   * the result is `"bar"`.
   */
-  string getMethodName() { none() }
+  final string getMethodName() { result = this.(MethodCallImpl).getMethodNameImpl() }

  /**
   * Gets the block of this method call, if any.
@@ -111,13 +111,7 @@ class MethodCall extends Call, TMethodCall {
 * ```
 */
 class SetterMethodCall extends MethodCall {
-  SetterMethodCall() {
-    this instanceof LhsExpr
-    or
-    this = any(Assignment a).getDesugared()
-    or
-    this = any(Assignment a).getDesugared().(StmtSequence).getAStmt()
-  }
+  SetterMethodCall() { this = TMethodCallSynth(_, _, _, true, _) }

  final override string getAPrimaryQlClass() { result = "SetterMethodCall" }
 }
@@ -131,8 +125,6 @@ class SetterMethodCall extends MethodCall {
 class ElementReference extends MethodCall, TElementReference {
  final override string getAPrimaryQlClass() { result = "ElementReference" }

-  final override string getMethodName() { result = getMethodName(this, "[]") }
-
  final override string toString() { result = "...[...]" }
 }

--- a/ql/src/codeql_ruby/ast/internal/AST.qll
+++ b/ql/src/codeql_ruby/ast/internal/AST.qll
@@ -115,10 +115,7 @@ private module Cached {
    TDivExprSynth(AST::AstNode parent, int i) { mkSynthChild(DivExprKind(), parent, i) } or
    TDo(Generated::Do g) or
    TDoBlock(Generated::DoBlock g) { not g.getParent() instanceof Generated::Lambda } or
-    TElementReferenceReal(Generated::ElementReference g) or
-    TElementReferenceSynth(AST::AstNode parent, int i) {
-      mkSynthChild(ElementReferenceKind(), parent, i)
-    } or
+    TElementReference(Generated::ElementReference g) or
    TElse(Generated::Else g) or
    TElsif(Generated::Elsif g) or
    TEmptyStmt(Generated::EmptyStatement g) or
@@ -183,8 +180,8 @@ private module Cached {
    } or
    TLogicalOrExprSynth(AST::AstNode parent, int i) { mkSynthChild(LogicalOrExprKind(), parent, i) } or
    TMethod(Generated::Method g) or
-    TMethodCallSynth(AST::AstNode parent, int i, string name) {
-      mkSynthChild(MethodCallKind(name), parent, i)
+    TMethodCallSynth(AST::AstNode parent, int i, string name, boolean setter, int arity) {
+      mkSynthChild(MethodCallKind(name, setter, arity), parent, i)
    } or
    TModuleDeclaration(Generated::Module g) or
    TModuloExprReal(Generated::Binary g) { g instanceof @binary_percent } or
@@ -323,7 +320,7 @@ private module Cached {
    n = TDivExprReal(result) or
    n = TDo(result) or
    n = TDoBlock(result) or
-    n = TElementReferenceReal(result) or
+    n = TElementReference(result) or
    n = TElse(result) or
    n = TElsif(result) or
    n = TEmptyStmt(result) or
@@ -439,8 +436,6 @@ private module Cached {
    or
    result = TDivExprSynth(parent, i)
    or
-    result = TElementReferenceSynth(parent, i)
-    or
    result = TExponentExprSynth(parent, i)
    or
    result = TGlobalVariableAccessSynth(parent, i, _)
@@ -457,7 +452,7 @@ private module Cached {
    or
    result = TLogicalOrExprSynth(parent, i)
    or
-    result = TMethodCallSynth(parent, i, _)
+    result = TMethodCallSynth(parent, i, _, _, _)
    or
    result = TModuloExprSynth(parent, i)
    or
@@ -524,8 +519,6 @@ class TMethodCall =
  TMethodCallSynth or TIdentifierMethodCall or TScopeResolutionMethodCall or TRegularMethodCall or
      TElementReference or TSuperCall;

-class TElementReference = TElementReferenceReal or TElementReferenceSynth;
-
 class TSuperCall = TTokenSuperCall or TRegularSuperCall;

 class TConstantAccess = TTokenConstantAccess or TScopeResolutionConstantAccess or TNamespace;
--- a/ql/src/codeql_ruby/ast/internal/Call.qll
+++ b/ql/src/codeql_ruby/ast/internal/Call.qll
@@ -7,37 +7,11 @@ predicate isIdentifierMethodCall(Generated::Identifier g) { vcall(g) and not acc

 predicate isRegularMethodCall(Generated::Call g) { not g.getMethod() instanceof Generated::Super }

-string regularMethodCallName(Generated::Call g) {
-  isRegularMethodCall(g) and
-  (
-    result = "call" and g.getMethod() instanceof Generated::ArgumentList
-    or
-    result = g.getMethod().(Generated::Token).getValue()
-    or
-    result = g.getMethod().(Generated::ScopeResolution).getName().(Generated::Token).getValue()
-  )
-}
-
 predicate isScopeResolutionMethodCall(Generated::ScopeResolution g, Generated::Identifier i) {
  i = g.getName() and
  not exists(Generated::Call c | c.getMethod() = g)
 }

-string methodCallName(MethodCall mc) {
-  exists(Generated::AstNode g | g = toGenerated(mc) |
-    isIdentifierMethodCall(g) and result = g.(Generated::Identifier).getValue()
-    or
-    result = regularMethodCallName(g)
-    or
-    isScopeResolutionMethodCall(g, any(Generated::Identifier i | result = i.getValue()))
-  )
-}
-
-bindingset[s]
-string getMethodName(MethodCall mc, string s) {
-  if mc instanceof SetterMethodCall then result = s + "=" else result = s
-}
-
 abstract class CallImpl extends Call {
  abstract Expr getArgumentImpl(int n);

@@ -55,21 +29,16 @@ abstract class CallImpl extends Call {

 abstract class MethodCallImpl extends CallImpl, MethodCall {
  abstract Expr getReceiverImpl();
-}

-/**
- * Gets the special integer literal used to specify the number of arguments
- * in a synthesized call.
- */
-private TIntegerLiteralSynth getNumberOfArgumentsSynth(MethodCall mc, int value) {
-  result = TIntegerLiteralSynth(mc, -2, value)
+  abstract string getMethodNameImpl();
 }

 class MethodCallSynth extends MethodCallImpl, TMethodCallSynth {
-  final override string getMethodName() {
-    exists(string name |
-      this = TMethodCallSynth(_, _, name) and
-      result = getMethodName(this, name)
+  final override string getMethodNameImpl() {
+    exists(boolean setter, string name | this = TMethodCallSynth(_, _, name, setter, _) |
+      setter = true and result = name + "="
+      or
+      setter = false and result = name
    )
  }

@@ -77,14 +46,7 @@ class MethodCallSynth extends MethodCallImpl, TMethodCallSynth {

  final override Expr getArgumentImpl(int n) { synthChild(this, n + 1, result) and n >= 0 }

-  final override int getNumberOfArgumentsImpl() { exists(getNumberOfArgumentsSynth(this, result)) }
-
-  final override AstNode getAChild(string pred) {
-    result = super.getAChild(pred)
-    or
-    pred = "getNumberOfArguments" and
-    result = getNumberOfArgumentsSynth(this, _)
-  }
+  final override int getNumberOfArgumentsImpl() { this = TMethodCallSynth(_, _, _, _, result) }
 }

 class IdentifierMethodCall extends MethodCallImpl, TIdentifierMethodCall {
@@ -92,7 +54,7 @@ class IdentifierMethodCall extends MethodCallImpl, TIdentifierMethodCall {

  IdentifierMethodCall() { this = TIdentifierMethodCall(g) }

-  final override string getMethodName() { result = getMethodName(this, g.getValue()) }
+  final override string getMethodNameImpl() { result = g.getValue() }

  final override Self getReceiverImpl() { result = TSelfSynth(this, 0) }

@@ -107,7 +69,7 @@ class ScopeResolutionMethodCall extends MethodCallImpl, TScopeResolutionMethodCa

  ScopeResolutionMethodCall() { this = TScopeResolutionMethodCall(g, i) }

-  final override string getMethodName() { result = getMethodName(this, i.getValue()) }
+  final override string getMethodNameImpl() { result = i.getValue() }

  final override Expr getReceiverImpl() { toGenerated(result) = g.getScope() }

@@ -130,7 +92,16 @@ class RegularMethodCall extends MethodCallImpl, TRegularMethodCall {
    result = TSelfSynth(this, 0)
  }

-  final override string getMethodName() { result = getMethodName(this, regularMethodCallName(g)) }
+  final override string getMethodNameImpl() {
+    isRegularMethodCall(g) and
+    (
+      result = "call" and g.getMethod() instanceof Generated::ArgumentList
+      or
+      result = g.getMethod().(Generated::Token).getValue()
+      or
+      result = g.getMethod().(Generated::ScopeResolution).getName().(Generated::Token).getValue()
+    )
+  }

  final override Expr getArgumentImpl(int n) {
    toGenerated(result) = g.getArguments().getChild(n)
@@ -147,39 +118,32 @@ class RegularMethodCall extends MethodCallImpl, TRegularMethodCall {
  final override Block getBlock() { toGenerated(result) = g.getBlock() }
 }

-class ElementReferenceReal extends MethodCallImpl, TElementReferenceReal {
+class ElementReferenceImpl extends MethodCallImpl, TElementReference {
  private Generated::ElementReference g;

-  ElementReferenceReal() { this = TElementReferenceReal(g) }
+  ElementReferenceImpl() { this = TElementReference(g) }

  final override Expr getReceiverImpl() { toGenerated(result) = g.getObject() }

  final override Expr getArgumentImpl(int n) { toGenerated(result) = g.getChild(n) }

  final override int getNumberOfArgumentsImpl() { result = count(g.getChild(_)) }
+
+  final override string getMethodNameImpl() { result = "[]" }
 }

-class ElementReferenceSynth extends MethodCallImpl, TElementReferenceSynth {
-  final override Expr getReceiverImpl() { synthChild(this, 0, result) }
-
-  final override Expr getArgumentImpl(int n) { synthChild(this, n + 1, result) and n >= 0 }
-
-  final override int getNumberOfArgumentsImpl() { exists(getNumberOfArgumentsSynth(this, result)) }
-
-  final override AstNode getAChild(string pred) {
-    result = super.getAChild(pred)
-    or
-    pred = "getNumberOfArguments" and
-    result = getNumberOfArgumentsSynth(this, _)
-  }
-}
-
-class TokenSuperCall extends SuperCall, TTokenSuperCall {
+class TokenSuperCall extends SuperCall, MethodCallImpl, TTokenSuperCall {
  private Generated::Super g;

  TokenSuperCall() { this = TTokenSuperCall(g) }

-  final override string getMethodName() { result = getMethodName(this, g.getValue()) }
+  final override string getMethodNameImpl() { result = g.getValue() }
+
+  final override Expr getReceiverImpl() { none() }
+
+  final override Expr getArgumentImpl(int n) { none() }
+
+  final override int getNumberOfArgumentsImpl() { result = 0 }
 }

 class RegularSuperCall extends SuperCall, MethodCallImpl, TRegularSuperCall {
@@ -187,9 +151,7 @@ class RegularSuperCall extends SuperCall, MethodCallImpl, TRegularSuperCall {

  RegularSuperCall() { this = TRegularSuperCall(g) }

-  final override string getMethodName() {
-    result = getMethodName(this, g.getMethod().(Generated::Super).getValue())
-  }
+  final override string getMethodNameImpl() { result = g.getMethod().(Generated::Super).getValue() }

  final override Expr getReceiverImpl() { none() }

--- a/ql/src/codeql_ruby/ast/internal/Synthesis.qll
+++ b/ql/src/codeql_ruby/ast/internal/Synthesis.qll
@@ -17,7 +17,6 @@ newtype SynthKind =
  BitwiseXorExprKind() or
  ClassVariableAccessKind(ClassVariable v) or
  DivExprKind() or
-  ElementReferenceKind() or
  ExponentExprKind() or
  GlobalVariableAccessKind(GlobalVariable v) or
  InstanceVariableAccessKind(InstanceVariable v) or
@@ -27,12 +26,8 @@ newtype SynthKind =
  LocalVariableAccessSynthKind(TLocalVariableSynth v) or
  LogicalAndExprKind() or
  LogicalOrExprKind() or
-  MethodCallKind(string name) {
-    exists(Generated::Identifier g | isIdentifierMethodCall(g) and name = g.getValue())
-    or
-    exists(Generated::Identifier i | isScopeResolutionMethodCall(_, i) and name = i.getValue())
-    or
-    name = regularMethodCallName(_)
+  MethodCallKind(string name, boolean setter, int arity) {
+    any(Synthesis s).methodCall(name, setter, arity)
  } or
  ModuloExprKind() or
  MulExprKind() or
@@ -75,6 +70,11 @@ class Synthesis extends TSynthesis {
   */
  predicate localVariable(AstNode n, int i) { none() }

+  /**
+   * Holds if a method call to `name` with arity `arity` is needed.
+   */
+  predicate methodCall(string name, boolean setter, int arity) { none() }
+
  /**
   * Holds if `n` should be excluded from `ControlFlowTree` in the CFG construction.
   */
@@ -107,11 +107,9 @@ private predicate assign(
  )
 }

-private SynthKind getCallKind(MethodCall mc) {
-  result = MethodCallKind(methodCallName(mc))
-  or
-  mc instanceof ElementReference and
-  result = ElementReferenceKind()
+bindingset[arity, setter]
+private SynthKind getCallKind(MethodCall mc, boolean setter, int arity) {
+  result = MethodCallKind(mc.getMethodName(), setter, arity)
 }

 private SomeLocation getSomeLocation(AstNode n) {
@@ -169,7 +167,7 @@ private module SetterDesugar {
        exists(AstNode seq | seq = getSynthChild(ae, -1) |
          parent = seq and
          i = 0 and
-          child = SynthChild(getCallKind(mc)) and
+          child = SynthChild(getCallKind(mc, true, mc.getNumberOfArguments() + 1)) and
          l = getSomeLocation(mc)
          or
          exists(AstNode call | call = getSynthChild(seq, 0) |
@@ -197,12 +195,6 @@ private module SetterDesugar {
                child = RealChild(ae.getRightOperand())
              )
            )
-            or
-            parent = call and
-            // special "number of arguments argument"; required to avoid non-monotonic recursion
-            i = -2 and
-            child = SynthChild(IntegerLiteralKind(mc.getNumberOfArguments() + 1)) and
-            l = NoneLocation()
          )
          or
          parent = seq and
@@ -221,6 +213,15 @@ private module SetterDesugar {
      n.(AssignExpr).getLeftOperand() instanceof MethodCall and
      i = 0
    }
+
+    final override predicate methodCall(string name, boolean setter, int arity) {
+      exists(AssignExpr ae, MethodCall mc |
+        mc = ae.getLeftOperand() and
+        name = mc.getMethodName() and
+        setter = true and
+        arity = mc.getNumberOfArguments() + 1
+      )
+    }
  }
 }

@@ -380,7 +381,7 @@ private module AssignOperationDesugar {
              exists(AstNode op | op = getSynthChild(assign, 1) |
                parent = op and
                i = 0 and
-                child = SynthChild(getCallKind(mc)) and
+                child = SynthChild(getCallKind(mc, false, mc.getNumberOfArguments())) and
                l = getSomeLocation(mc)
                or
                parent = getSynthChild(op, 0) and
@@ -402,7 +403,7 @@ private module AssignOperationDesugar {
            // `__synth__0.[]=(__synth__1, __synth__2);`
            parent = seq and
            i = opAssignIndex + 1 and
-            child = SynthChild(getCallKind(mc)) and
+            child = SynthChild(getCallKind(mc, true, opAssignIndex)) and
            l = getSomeLocation(mc)
            or
            exists(AstNode setter | setter = getSynthChild(seq, opAssignIndex + 1) |
@@ -420,12 +421,6 @@ private module AssignOperationDesugar {
              child =
                SynthChild(LocalVariableAccessSynthKind(TLocalVariableSynth(ao, opAssignIndex))) and
              l = SomeLocation(getAssignOperationLocation(ao))
-              or
-              // special "number of arguments argument"; required to avoid non-monotonic recursion
-              parent = setter and
-              i = -2 and
-              child = SynthChild(IntegerLiteralKind(opAssignIndex + 1)) and
-              l = NoneLocation()
            )
            or
            parent = seq and
@@ -443,6 +438,18 @@ private module AssignOperationDesugar {
      )
    }

+    final override predicate methodCall(string name, boolean setter, int arity) {
+      exists(MethodCall mc | exists(assignOperationMethodCall(mc)) |
+        name = mc.getMethodName() and
+        setter = false and
+        arity = mc.getNumberOfArguments()
+        or
+        name = mc.getMethodName() and
+        setter = true and
+        arity = mc.getNumberOfArguments() + 1
+      )
+    }
+
    final override predicate excludeFromControlFlowTree(AstNode n) {
      exists(assignOperationMethodCall(n))
    }
--- a/ql/test/library-tests/ast/Ast.expected
+++ b/ql/test/library-tests/ast/Ast.expected
@@ -522,22 +522,22 @@ calls/calls.rb:
 #  311|       getReceiver: [Self] self
 #  311|     getArgument: [IntegerLiteral] 1
 #  314|   getStmt: [AssignExpr] ... = ...
-#  314|     getAnOperand/getLeftOperand: [SetterMethodCall] call to foo=
+#  314|     getAnOperand/getLeftOperand: [MethodCall] call to foo
 #  314|       getReceiver: [Self] self
 #  314|     getAnOperand/getRightOperand: [IntegerLiteral] 10
 #  315|   getStmt: [AssignExpr] ... = ...
-#  315|     getAnOperand/getLeftOperand: [ElementReference, SetterMethodCall] ...[...]
+#  315|     getAnOperand/getLeftOperand: [ElementReference] ...[...]
 #  315|       getReceiver: [MethodCall] call to foo
 #  315|         getReceiver: [Self] self
 #  315|       getArgument: [IntegerLiteral] 0
 #  315|     getAnOperand/getRightOperand: [IntegerLiteral] 10
 #  316|   getStmt: [AssignExpr] ... = ...
 #  316|     getLeftOperand: [TuplePattern] (..., ...)
-#  316|       getElement: [SetterMethodCall] call to foo=
+#  316|       getElement: [MethodCall] call to foo
 #  316|         getReceiver: [Self] self
-#  316|       getElement: [SetterMethodCall] call to bar=
+#  316|       getElement: [MethodCall] call to bar
 #  316|         getReceiver: [Self] self
-#  316|       getElement: [ElementReference, SetterMethodCall] ...[...]
+#  316|       getElement: [ElementReference] ...[...]
 #  316|         getReceiver: [MethodCall] call to foo
 #  316|           getReceiver: [Self] self
 #  316|         getArgument: [IntegerLiteral] 4
@@ -549,7 +549,7 @@ calls/calls.rb:
 #  317|   getStmt: [AssignExpr] ... = ...
 #  317|     getLeftOperand: [TuplePattern] (..., ...)
 #  317|       getElement: [LocalVariableAccess] a
-#  317|       getElement: [ElementReference, SetterMethodCall] ...[...]
+#  317|       getElement: [ElementReference] ...[...]
 #  317|         getReceiver: [MethodCall] call to foo
 #  317|           getReceiver: [Self] self
 #  317|         getArgument: [IntegerLiteral] 5
@@ -558,17 +558,17 @@ calls/calls.rb:
 #  317|       getElement: [IntegerLiteral] 2
 #  317|       getElement: [IntegerLiteral] 3
 #  318|   getStmt: [AssignAddExpr] ... += ...
-#  318|     getAnOperand/getLeftOperand: [SetterMethodCall] call to count=
+#  318|     getAnOperand/getLeftOperand: [MethodCall] call to count
 #  318|       getReceiver: [Self] self
 #  318|     getAnOperand/getRightOperand: [IntegerLiteral] 1
 #  319|   getStmt: [AssignAddExpr] ... += ...
-#  319|     getAnOperand/getLeftOperand: [ElementReference, SetterMethodCall] ...[...]
+#  319|     getAnOperand/getLeftOperand: [ElementReference] ...[...]
 #  319|       getReceiver: [MethodCall] call to foo
 #  319|         getReceiver: [Self] self
 #  319|       getArgument: [IntegerLiteral] 0
 #  319|     getAnOperand/getRightOperand: [IntegerLiteral] 1
 #  320|   getStmt: [AssignMulExpr] ... *= ...
-#  320|     getAnOperand/getLeftOperand: [ElementReference, SetterMethodCall] ...[...]
+#  320|     getAnOperand/getLeftOperand: [ElementReference] ...[...]
 #  320|       getReceiver: [MethodCall] call to bar
 #  320|         getReceiver: [MethodCall] call to foo
 #  320|           getReceiver: [Self] self
--- a/ql/test/library-tests/ast/AstDesugar.expected
+++ b/ql/test/library-tests/ast/AstDesugar.expected
@@ -14,16 +14,14 @@ calls/calls.rb:
 #  314| [StmtSequence] ...
 #  314|   getStmt: [SetterMethodCall] call to foo=
 #  314|     getReceiver: [Self] self
-#  314|     getNumberOfArguments: [IntegerLiteral] 1
 #  314|     getArgument: [AssignExpr] ... = ...
 #  314|       getAnOperand/getLeftOperand: [LocalVariableAccess] __synth__0
 #  314|       getAnOperand/getRightOperand: [IntegerLiteral] 10
 #  314|   getStmt: [LocalVariableAccess] __synth__0
 #  315| [StmtSequence] ...
-#  315|   getStmt: [ElementReference, SetterMethodCall] ...[...]
+#  315|   getStmt: [SetterMethodCall] call to []=
 #  315|     getReceiver: [MethodCall] call to foo
 #  315|       getReceiver: [Self] self
-#  315|     getNumberOfArguments: [IntegerLiteral] 2
 #  315|     getArgument: [AssignExpr] ... = ...
 #  315|       getAnOperand/getLeftOperand: [LocalVariableAccess] __synth__0
 #  315|       getAnOperand/getRightOperand: [IntegerLiteral] 10
@@ -31,7 +29,6 @@ calls/calls.rb:
 #  315|   getStmt: [LocalVariableAccess] __synth__0
 #  318| [StmtSequence] ...
 #  318|   getStmt: [SetterMethodCall] call to count=
-#  318|     getNumberOfArguments: [IntegerLiteral] 2
 #  318|     getReceiver: [LocalVariableAccess] __synth__0
 #  318|     getArgument: [LocalVariableAccess] __synth__1
 #  318|   getStmt: [AssignExpr] ... = ...
@@ -45,40 +42,38 @@ calls/calls.rb:
 #  318|     getAnOperand/getLeftOperand: [LocalVariableAccess] __synth__1
 #  318|   getStmt: [LocalVariableAccess] __synth__1
 #  319| [StmtSequence] ...
+#  319|   getStmt: [SetterMethodCall] call to []=
+#  319|     getReceiver: [LocalVariableAccess] __synth__0
+#  319|     getArgument: [LocalVariableAccess] __synth__1
+#  319|     getArgument: [LocalVariableAccess] __synth__2
 #  319|   getStmt: [AssignExpr] ... = ...
 #  319|     getAnOperand/getRightOperand: [MethodCall] call to foo
 #  319|       getReceiver: [Self] self
 #  319|     getAnOperand/getLeftOperand: [LocalVariableAccess] __synth__0
-#  319|   getStmt: [ElementReference, SetterMethodCall] ...[...]
-#  319|     getNumberOfArguments: [IntegerLiteral] 3
-#  319|     getReceiver: [LocalVariableAccess] __synth__0
-#  319|     getArgument: [LocalVariableAccess] __synth__1
-#  319|     getArgument: [LocalVariableAccess] __synth__2
 #  319|   getStmt: [AssignExpr] ... = ...
 #  319|     getAnOperand/getRightOperand: [IntegerLiteral] 0
 #  319|     getAnOperand/getLeftOperand: [LocalVariableAccess] __synth__1
 #  319|   getStmt: [AssignExpr] ... = ...
 #  319|     getAnOperand/getRightOperand: [AddExpr] ... + ...
-#  319|       getAnOperand/getLeftOperand: [ElementReference] ...[...]
+#  319|       getAnOperand/getLeftOperand: [MethodCall] call to []
 #  319|         getReceiver: [LocalVariableAccess] __synth__0
 #  319|         getArgument: [LocalVariableAccess] __synth__1
 #  319|       getAnOperand/getRightOperand: [IntegerLiteral] 1
 #  319|     getAnOperand/getLeftOperand: [LocalVariableAccess] __synth__2
 #  319|   getStmt: [LocalVariableAccess] __synth__2
 #  320| [StmtSequence] ...
-#  320|   getStmt: [AssignExpr] ... = ...
-#  320|     getAnOperand/getRightOperand: [MethodCall] call to bar
-#  320|       getReceiver: [MethodCall] call to foo
-#  320|         getReceiver: [Self] self
-#  320|     getAnOperand/getLeftOperand: [LocalVariableAccess] __synth__0
-#  320|   getStmt: [ElementReference, SetterMethodCall] ...[...]
-#  320|     getNumberOfArguments: [IntegerLiteral] 5
+#  320|   getStmt: [SetterMethodCall] call to []=
 #  320|     getReceiver: [LocalVariableAccess] __synth__0
 #  320|     getArgument: [LocalVariableAccess] __synth__1
 #  320|     getArgument: [LocalVariableAccess] __synth__2
 #  320|     getArgument: [LocalVariableAccess] __synth__3
 #  320|     getArgument: [LocalVariableAccess] __synth__4
 #  320|   getStmt: [AssignExpr] ... = ...
+#  320|     getAnOperand/getRightOperand: [MethodCall] call to bar
+#  320|       getReceiver: [MethodCall] call to foo
+#  320|         getReceiver: [Self] self
+#  320|     getAnOperand/getLeftOperand: [LocalVariableAccess] __synth__0
+#  320|   getStmt: [AssignExpr] ... = ...
 #  320|     getAnOperand/getRightOperand: [IntegerLiteral] 0
 #  320|     getAnOperand/getLeftOperand: [LocalVariableAccess] __synth__1
 #  320|   getStmt: [AssignExpr] ... = ...
@@ -95,7 +90,7 @@ calls/calls.rb:
 #  320|     getAnOperand/getLeftOperand: [LocalVariableAccess] __synth__3
 #  320|   getStmt: [AssignExpr] ... = ...
 #  320|     getAnOperand/getRightOperand: [MulExpr] ... * ...
-#  320|       getAnOperand/getLeftOperand: [ElementReference] ...[...]
+#  320|       getAnOperand/getLeftOperand: [MethodCall] call to []
 #  320|         getReceiver: [LocalVariableAccess] __synth__0
 #  320|         getArgument: [LocalVariableAccess] __synth__1
 #  320|         getArgument: [LocalVariableAccess] __synth__2
--- a/ql/test/library-tests/ast/calls/calls.expected
+++ b/ql/test/library-tests/ast/calls/calls.expected
@@ -32,26 +32,26 @@ callsWithArguments
 | calls.rb:293:5:293:33 | call to super | super | 1 | calls.rb:293:14:293:14 | 7 |
 | calls.rb:311:1:311:7 | call to call | call | 0 | calls.rb:311:6:311:6 | 1 |
 | calls.rb:314:1:314:8 | call to foo= | foo= | 0 | calls.rb:314:1:314:8 | ... = ... |
-| calls.rb:315:1:315:6 | ...[...] | []= | 0 | calls.rb:315:5:315:5 | 0 |
-| calls.rb:315:1:315:6 | ...[...] | []= | 0 | calls.rb:315:5:315:5 | 0 |
-| calls.rb:315:1:315:6 | ...[...] | []= | 1 | calls.rb:315:1:315:6 | ... = ... |
-| calls.rb:316:22:316:27 | ...[...] | []= | 0 | calls.rb:316:26:316:26 | 4 |
-| calls.rb:317:5:317:10 | ...[...] | []= | 0 | calls.rb:317:9:317:9 | 5 |
+| calls.rb:315:1:315:6 | ...[...] | [] | 0 | calls.rb:315:5:315:5 | 0 |
+| calls.rb:315:1:315:6 | call to []= | []= | 0 | calls.rb:315:5:315:5 | 0 |
+| calls.rb:315:1:315:6 | call to []= | []= | 1 | calls.rb:315:1:315:6 | ... = ... |
+| calls.rb:316:22:316:27 | ...[...] | [] | 0 | calls.rb:316:26:316:26 | 4 |
+| calls.rb:317:5:317:10 | ...[...] | [] | 0 | calls.rb:317:9:317:9 | 5 |
 | calls.rb:318:1:318:10 | call to count= | count= | 1 | calls.rb:318:12:318:13 | __synth__1 |
-| calls.rb:319:1:319:6 | ...[...] | [] | 0 | calls.rb:319:5:319:5 | __synth__1 |
-| calls.rb:319:1:319:6 | ...[...] | []= | 0 | calls.rb:319:5:319:5 | 0 |
-| calls.rb:319:1:319:6 | ...[...] | []= | 0 | calls.rb:319:5:319:5 | __synth__1 |
-| calls.rb:319:1:319:6 | ...[...] | []= | 2 | calls.rb:319:8:319:9 | __synth__2 |
-| calls.rb:320:1:320:32 | ...[...] | [] | 0 | calls.rb:320:9:320:9 | __synth__1 |
-| calls.rb:320:1:320:32 | ...[...] | [] | 1 | calls.rb:320:12:320:18 | __synth__2 |
-| calls.rb:320:1:320:32 | ...[...] | [] | 2 | calls.rb:320:21:320:31 | __synth__3 |
-| calls.rb:320:1:320:32 | ...[...] | []= | 0 | calls.rb:320:9:320:9 | 0 |
-| calls.rb:320:1:320:32 | ...[...] | []= | 0 | calls.rb:320:9:320:9 | __synth__1 |
-| calls.rb:320:1:320:32 | ...[...] | []= | 1 | calls.rb:320:12:320:18 | __synth__2 |
-| calls.rb:320:1:320:32 | ...[...] | []= | 1 | calls.rb:320:12:320:18 | call to baz |
-| calls.rb:320:1:320:32 | ...[...] | []= | 2 | calls.rb:320:21:320:31 | ... + ... |
-| calls.rb:320:1:320:32 | ...[...] | []= | 2 | calls.rb:320:21:320:31 | __synth__3 |
-| calls.rb:320:1:320:32 | ...[...] | []= | 4 | calls.rb:320:34:320:35 | __synth__4 |
+| calls.rb:319:1:319:6 | ...[...] | [] | 0 | calls.rb:319:5:319:5 | 0 |
+| calls.rb:319:1:319:6 | call to [] | [] | 0 | calls.rb:319:5:319:5 | __synth__1 |
+| calls.rb:319:1:319:6 | call to []= | []= | 0 | calls.rb:319:5:319:5 | __synth__1 |
+| calls.rb:319:1:319:6 | call to []= | []= | 2 | calls.rb:319:8:319:9 | __synth__2 |
+| calls.rb:320:1:320:32 | ...[...] | [] | 0 | calls.rb:320:9:320:9 | 0 |
+| calls.rb:320:1:320:32 | ...[...] | [] | 1 | calls.rb:320:12:320:18 | call to baz |
+| calls.rb:320:1:320:32 | ...[...] | [] | 2 | calls.rb:320:21:320:31 | ... + ... |
+| calls.rb:320:1:320:32 | call to [] | [] | 0 | calls.rb:320:9:320:9 | __synth__1 |
+| calls.rb:320:1:320:32 | call to [] | [] | 1 | calls.rb:320:12:320:18 | __synth__2 |
+| calls.rb:320:1:320:32 | call to [] | [] | 2 | calls.rb:320:21:320:31 | __synth__3 |
+| calls.rb:320:1:320:32 | call to []= | []= | 0 | calls.rb:320:9:320:9 | __synth__1 |
+| calls.rb:320:1:320:32 | call to []= | []= | 1 | calls.rb:320:12:320:18 | __synth__2 |
+| calls.rb:320:1:320:32 | call to []= | []= | 2 | calls.rb:320:21:320:31 | __synth__3 |
+| calls.rb:320:1:320:32 | call to []= | []= | 4 | calls.rb:320:34:320:35 | __synth__4 |
 callsWithReceiver
 | calls.rb:2:1:2:5 | call to foo | calls.rb:2:1:2:5 | self |
 | calls.rb:5:1:5:10 | call to bar | calls.rb:5:1:5:3 | Foo |
@@ -220,29 +220,29 @@ callsWithReceiver
 | calls.rb:310:1:310:6 | call to call | calls.rb:310:1:310:3 | call to foo |
 | calls.rb:311:1:311:3 | call to foo | calls.rb:311:1:311:3 | self |
 | calls.rb:311:1:311:7 | call to call | calls.rb:311:1:311:3 | call to foo |
-| calls.rb:314:1:314:8 | call to foo= | calls.rb:314:1:314:4 | self |
+| calls.rb:314:1:314:8 | call to foo | calls.rb:314:1:314:4 | self |
 | calls.rb:314:1:314:8 | call to foo= | calls.rb:314:1:314:4 | self |
 | calls.rb:315:1:315:3 | call to foo | calls.rb:315:1:315:3 | self |
 | calls.rb:315:1:315:6 | ...[...] | calls.rb:315:1:315:3 | call to foo |
-| calls.rb:315:1:315:6 | ...[...] | calls.rb:315:1:315:3 | call to foo |
-| calls.rb:316:1:316:8 | call to foo= | calls.rb:316:1:316:4 | self |
-| calls.rb:316:12:316:19 | call to bar= | calls.rb:316:12:316:15 | self |
+| calls.rb:315:1:315:6 | call to []= | calls.rb:315:1:315:3 | call to foo |
+| calls.rb:316:1:316:8 | call to foo | calls.rb:316:1:316:4 | self |
+| calls.rb:316:12:316:19 | call to bar | calls.rb:316:12:316:15 | self |
 | calls.rb:316:22:316:24 | call to foo | calls.rb:316:22:316:24 | self |
 | calls.rb:316:22:316:27 | ...[...] | calls.rb:316:22:316:24 | call to foo |
 | calls.rb:317:5:317:7 | call to foo | calls.rb:317:5:317:7 | self |
 | calls.rb:317:5:317:10 | ...[...] | calls.rb:317:5:317:7 | call to foo |
 | calls.rb:318:1:318:10 | call to count | calls.rb:318:1:318:4 | __synth__0 |
+| calls.rb:318:1:318:10 | call to count | calls.rb:318:1:318:4 | self |
 | calls.rb:318:1:318:10 | call to count= | calls.rb:318:1:318:4 | __synth__0 |
-| calls.rb:318:1:318:10 | call to count= | calls.rb:318:1:318:4 | self |
 | calls.rb:319:1:319:3 | call to foo | calls.rb:319:1:319:3 | self |
-| calls.rb:319:1:319:6 | ...[...] | calls.rb:319:1:319:3 | __synth__0 |
-| calls.rb:319:1:319:6 | ...[...] | calls.rb:319:1:319:3 | __synth__0 |
 | calls.rb:319:1:319:6 | ...[...] | calls.rb:319:1:319:3 | call to foo |
+| calls.rb:319:1:319:6 | call to [] | calls.rb:319:1:319:3 | __synth__0 |
+| calls.rb:319:1:319:6 | call to []= | calls.rb:319:1:319:3 | __synth__0 |
 | calls.rb:320:1:320:3 | call to foo | calls.rb:320:1:320:3 | self |
 | calls.rb:320:1:320:7 | call to bar | calls.rb:320:1:320:3 | call to foo |
-| calls.rb:320:1:320:32 | ...[...] | calls.rb:320:1:320:7 | __synth__0 |
-| calls.rb:320:1:320:32 | ...[...] | calls.rb:320:1:320:7 | __synth__0 |
 | calls.rb:320:1:320:32 | ...[...] | calls.rb:320:1:320:7 | call to bar |
+| calls.rb:320:1:320:32 | call to [] | calls.rb:320:1:320:7 | __synth__0 |
+| calls.rb:320:1:320:32 | call to []= | calls.rb:320:1:320:7 | __synth__0 |
 | calls.rb:320:12:320:14 | call to foo | calls.rb:320:12:320:14 | self |
 | calls.rb:320:12:320:18 | call to baz | calls.rb:320:12:320:14 | call to foo |
 | calls.rb:320:21:320:23 | call to foo | calls.rb:320:21:320:23 | self |
@@ -286,16 +286,7 @@ superCallsWithBlock
 | calls.rb:293:5:293:33 | call to super | calls.rb:293:16:293:33 | do ... end |
 setterCalls
 | calls.rb:314:1:314:8 | call to foo= |
-| calls.rb:314:1:314:8 | call to foo= |
-| calls.rb:315:1:315:6 | ...[...] |
-| calls.rb:315:1:315:6 | ...[...] |
-| calls.rb:316:1:316:8 | call to foo= |
-| calls.rb:316:12:316:19 | call to bar= |
-| calls.rb:316:22:316:27 | ...[...] |
-| calls.rb:317:5:317:10 | ...[...] |
+| calls.rb:315:1:315:6 | call to []= |
 | calls.rb:318:1:318:10 | call to count= |
-| calls.rb:318:1:318:10 | call to count= |
-| calls.rb:319:1:319:6 | ...[...] |
-| calls.rb:319:1:319:6 | ...[...] |
-| calls.rb:320:1:320:32 | ...[...] |
-| calls.rb:320:1:320:32 | ...[...] |
+| calls.rb:319:1:319:6 | call to []= |
+| calls.rb:320:1:320:32 | call to []= |
--- a/ql/test/library-tests/controlflow/graph/Cfg.expected
+++ b/ql/test/library-tests/controlflow/graph/Cfg.expected
@@ -2173,14 +2173,14 @@ desugar.rb:
 #   10| ...
 #-----|  -> exit m3 (normal)

-#   10| ...[...]
+#   10| call to []=
 #-----|  -> __synth__0

 #   10| __synth__0
 #-----|  -> ...

 #   10| ... = ...
-#-----|  -> ...[...]
+#-----|  -> call to []=

 #   10| __synth__0
 #-----|  -> 1
@@ -2276,19 +2276,19 @@ desugar.rb:
 #   18| ...
 #-----|  -> exit m5 (normal)

+#   18| call to []=
+#-----|  -> __synth__4
+
 #   18| ... = ...
 #-----|  -> __synth__1

-#   18| ...[...]
-#-----|  -> __synth__4
+#   18| __synth__0
+#-----|  -> __synth__1

 #   18| __synth__0
 #-----|  -> x

-#   18| __synth__0
-#-----|  -> __synth__1
-
-#   18| ...[...]
+#   18| call to []
 #-----|  -> 1

 #   18| __synth__0
@@ -2301,10 +2301,10 @@ desugar.rb:
 #-----|  -> __synth__2

 #   18| __synth__1
-#-----|  -> 0
+#-----|  -> __synth__2

 #   18| __synth__1
-#-----|  -> __synth__2
+#-----|  -> 0

 #   18| __synth__1
 #-----|  -> __synth__2
@@ -2319,10 +2319,10 @@ desugar.rb:
 #-----|  -> __synth__3

 #   18| __synth__2
-#-----|  -> y
+#-----|  -> __synth__3

 #   18| __synth__2
-#-----|  -> __synth__3
+#-----|  -> y

 #   18| __synth__2
 #-----|  -> __synth__3
@@ -2339,14 +2339,14 @@ desugar.rb:
 #   18| ... = ...
 #-----|  -> __synth__4

-#   18| __synth__3
-#-----|  -> x
-
 #   18| __synth__3
 #-----|  -> __synth__4

 #   18| __synth__3
-#-----|  -> ...[...]
+#-----|  -> x
+
+#   18| __synth__3
+#-----|  -> call to []

 #   18| 3
 #-----|  -> ... + ...
@@ -2361,10 +2361,10 @@ desugar.rb:
 #-----|  -> ... = ...

 #   18| __synth__4
-#-----|  -> __synth__0
+#-----|  -> call to []=

 #   18| __synth__4
-#-----|  -> ...[...]
+#-----|  -> __synth__0

 #   18| 1
 #-----|  -> ... + ...