Use entities as keys rather than IR nodes

pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart

Index: pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
diff --git a/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart b/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
index 49b44a7a7bf5fd56cfbfda6bb8808a94e490f07d..b727f1309ef5e7e5bec3ad66e882401025a8cf88 100644
--- a/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
+++ b/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
@@ -126,14 +126,15 @@ class KernelAstAdapter extends KernelToElementMapMixin {
 
   /// Push the existing resolved AST on the stack and shift the current resolved
   /// AST to the AST that this kernel node points to.
-  void pushResolvedAst(ir.Node node) {
+  void enterInlinedMember(MemberElement member) {
     _resolvedAstStack.add(_resolvedAst);
-    _resolvedAst = (getElement(node) as AstElement).resolvedAst;
+    _resolvedAst = member.resolvedAst;
   }
 
   /// Pop the resolved AST stack to reset it to the previous resolved AST node.
-  void popResolvedAstStack() {
+  void leaveInlinedMember(MemberElement member) {
     assert(_resolvedAstStack.isNotEmpty);
+    assert(_resolvedAst.element == member);
     _resolvedAst = _resolvedAstStack.removeLast();
   }
 
@@ -226,26 +227,6 @@ class KernelAstAdapter extends KernelToElementMapMixin {
     return getElement(function).asFunctionElement().functionSignature;
   }
 
-  ir.Field getFieldFromElement(FieldElement field) {
-    return kernel.fields[field];
-  }
-
-  bool isFixedLength(TypeMask mask, ClosedWorld closedWorld) {
-    if (mask.isContainer && (mask as ContainerTypeMask).length != null) {
-      // A container on which we have inferred the length.
-      return true;
-    }
-    // TODO(sra): Recognize any combination of fixed length indexables.
-    if (mask.containsOnly(closedWorld.commonElements.jsFixedArrayClass) ||
-        mask.containsOnly(
-            closedWorld.commonElements.jsUnmodifiableArrayClass) ||
-        mask.containsOnlyString(closedWorld) ||
-        closedWorld.commonMasks.isTypedArray(mask)) {
-      return true;
-    }
-    return false;
-  }
-
   ConstantValue getConstantFor(ir.Node node) {
     // Some `null`s are not mapped when they correspond to errors, e.g. missing
     // `const` initializers.
@@ -340,11 +321,6 @@ class KernelAstAdapter extends KernelToElementMapMixin {
     return _typeConverter.convert(type);
   }
 
-  ResolutionDartType getDartTypeIfValid(ir.DartType type) {
-    if (type is ir.InvalidType) return null;
-    return _typeConverter.convert(type);
-  }
-
   List<ResolutionDartType> getDartTypes(List<ir.DartType> types) {
     return types.map(getDartType).toList();
   }
@@ -688,6 +664,22 @@ class KernelAstTypeInferenceMap implements KernelToTypeInferenceMap {
         !mask.satisfies(closedWorld.commonElements.jsStringClass, closedWorld);
   }
 
+  bool isFixedLength(TypeMask mask, ClosedWorld closedWorld) {
+    if (mask.isContainer && (mask as ContainerTypeMask).length != null) {
+      // A container on which we have inferred the length.
+      return true;
+    }
+    // TODO(sra): Recognize any combination of fixed length indexables.
+    if (mask.containsOnly(closedWorld.commonElements.jsFixedArrayClass) ||
+        mask.containsOnly(
+            closedWorld.commonElements.jsUnmodifiableArrayClass) ||
+        mask.containsOnlyString(closedWorld) ||
+        closedWorld.commonMasks.isTypedArray(mask)) {
+      return true;
+    }
+    return false;
+  }
+
   TypeMask inferredIndexType(ir.ForInStatement forInStatement) {
     return TypeMaskFactory.inferredTypeForSelector(new Selector.index(),
         typeOfIterator(forInStatement), _globalInferenceResults);