Always store GlobalTypeInferenceElementData on the member context

pkg/compiler/lib/src/inferrer/inferrer_engine.dart

Index: pkg/compiler/lib/src/inferrer/inferrer_engine.dart
diff --git a/pkg/compiler/lib/src/inferrer/inferrer_engine.dart b/pkg/compiler/lib/src/inferrer/inferrer_engine.dart
index 439d838e84a8f840805fb7e4bc36c8a8169f4dbf..40f80e43295a88dcdb94edc279c4f7ff9ff01718 100644
--- a/pkg/compiler/lib/src/inferrer/inferrer_engine.dart
+++ b/pkg/compiler/lib/src/inferrer/inferrer_engine.dart
@@ -77,8 +77,8 @@ class InferrerEngine {
 
   /// Data computed internally within elements, like the type-mask of a send a
   /// list allocation, or a for-in loop.
-  final Map<Element, GlobalTypeInferenceElementData> inTreeData =
-      new Map<Element, GlobalTypeInferenceElementData>();
+  final Map<MemberElement, GlobalTypeInferenceElementData> _memberData =
+      new Map<MemberElement, GlobalTypeInferenceElementData>();
 
   InferrerEngine(this.compiler, ClosedWorld closedWorld,
       this.closedWorldRefiner, this.mainElement)
@@ -110,16 +110,13 @@ class InferrerEngine {
     }
   }
 
-  GlobalTypeInferenceElementData dataOfLocalFunction(
-          LocalFunctionElement element) =>
-      _dataOf(element);
-
   // TODO(johnniwinther): Make this private again.
   GlobalTypeInferenceElementData dataOfMember(MemberElement element) =>
-      _dataOf(element);
+      _memberData.putIfAbsent(
+          element, () => new GlobalTypeInferenceElementData());
 
-  GlobalTypeInferenceElementData _dataOf(AstElement element) => inTreeData

[Johnni Winther, 2017/06/29 17:00:28]

It turned out that we never (after type inference) read the data stored on a
local function. 

After investigating this, it turned out that the addition of [_dataOf] in
https://codereview.chromium.org/2468303003 actually unintentionally introduced
this (local functions share the TreeElements with their member context).

Surprisingly, this didn't show any regression back then (as far as i know) -
though I suspect the inference might have become slower; taking more iterations
to reach the same fixed-point by starting from scratch instead of using the data
collected in the local function data.

-      .putIfAbsent(element, () => new GlobalTypeInferenceElementData());
+  GlobalTypeInferenceElementData lookupDataOfMember(MemberElement element) =>
+      _memberData[element];
 
   /**
    * Update [sideEffects] with the side effects of [callee] being
@@ -198,21 +195,9 @@ class InferrerEngine {
     return returnType;
   }
 
-  @deprecated
-  void updateSelectorInLocalFunction(LocalFunctionElement owner, Spannable node,
-      Selector selector, TypeMask mask) {
-    GlobalTypeInferenceElementData data = dataOfLocalFunction(owner);
-    _updateSelectorInTree(data, node, selector, mask);
-  }
-
   void updateSelectorInMember(
       MemberElement owner, Spannable node, Selector selector, TypeMask mask) {
     GlobalTypeInferenceElementData data = dataOfMember(owner);
-    _updateSelectorInTree(data, node, selector, mask);
-  }
-
-  void _updateSelectorInTree(GlobalTypeInferenceElementData data,
-      Spannable node, Selector selector, TypeMask mask) {
     ast.Node astNode = node;
     if (astNode.asSendSet() != null) {
       if (selector.isSetter || selector.isIndexSet) {
@@ -922,7 +907,7 @@ class InferrerEngine {
       Spannable node,
       Selector selector,
       TypeMask mask,
-      Element caller,
+      MemberElement caller,
       LocalFunctionElement callee,
       ArgumentsTypes arguments,
       SideEffects sideEffects,
@@ -953,7 +938,7 @@ class InferrerEngine {
       Spannable node,
       Selector selector,
       TypeMask mask,
-      Element caller,
+      MemberElement caller,
       MemberElement callee,
       ArgumentsTypes arguments,
       SideEffects sideEffects,
@@ -1013,7 +998,7 @@ class InferrerEngine {
       Selector selector,
       TypeMask mask,
       TypeInformation receiverType,
-      Element caller,
+      MemberElement caller,
       ArgumentsTypes arguments,
       SideEffects sideEffects,
       bool inLoop) {
@@ -1079,7 +1064,7 @@ class InferrerEngine {
       Selector selector,
       TypeMask mask,
       TypeInformation closure,
-      Element caller,
+      MemberElement caller,
       ArgumentsTypes arguments,
       SideEffects sideEffects,
       bool inLoop) {