Flow analysis: remove the State.exit method.

stereotype441 · commit-bot@chromium.org · commit 24c0507d735d · 2019-07-23T12:55:11.000Z
It was redundant with State.setReachable(false), and it did not have the necessary logic to avoid creating State objects when unnecessary. Change-Id: If9e0b8b586dab0e681f4ee0bc7b792d49e1e5f4b Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/109897 Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
diff --git a/pkg/analyzer/lib/src/dart/resolver/flow_analysis.dart b/pkg/analyzer/lib/src/dart/resolver/flow_analysis.dart
@@ -327,7 +327,7 @@ class FlowAnalysis<Statement, Expression, Variable, Type> {
     if (breakIndex != null) {
       _stack[breakIndex] = _join(_stack[breakIndex], _current);
     }
-    _current = _current.exit();
+    _current = _current.setReachable(false);
   }
 
   void handleContinue(Statement target) {
@@ -336,13 +336,13 @@ class FlowAnalysis<Statement, Expression, Variable, Type> {
       var continueIndex = breakIndex + 1;
       _stack[continueIndex] = _join(_stack[continueIndex], _current);
     }
-    _current = _current.exit();
+    _current = _current.setReachable(false);
   }
 
   /// Register the fact that the current state definitely exists, e.g. returns
   /// from the body, throws an exception, etc.
   void handleExit() {
-    _current = _current.exit();
+    _current = _current.setReachable(false);
   }
 
   void ifNullExpression_end() {
@@ -756,15 +756,6 @@ class State<Variable, Type> {
     );
   }
 
-  /// Updates the state to indicate that the control flow path is unreachable.
-  State<Variable, Type> exit() {
-    return State<Variable, Type>._(
-      false,
-      notAssigned,
-      promoted,
-    );
-  }
-
   /// Updates the state to indicate that the given [variable] has been
   /// determined to contain a non-null value.
   ///
diff --git a/pkg/analyzer/test/src/dart/resolution/flow_analysis_unit_test.dart b/pkg/analyzer/test/src/dart/resolution/flow_analysis_unit_test.dart
@@ -143,14 +143,6 @@ main() {
       });
     });
 
-    test('exit', () {
-      var s1 = State<_Var, _Type>(true);
-      var s2 = s1.exit();
-      expect(s2.reachable, false);
-      expect(s2.notAssigned, same(s1.notAssigned));
-      expect(s2.promoted, same(s1.promoted));
-    });
-
     group('promote', () {
       test('unpromoted -> unchanged (same)', () {
         var h = _Harness();
@@ -327,7 +319,7 @@ main() {
       test('reachability', () {
         var h = _Harness();
         var reachable = State<_Var, _Type>(true);
-        var unreachable = reachable.exit();
+        var unreachable = reachable.setReachable(false);
         expect(reachable.restrict(h, emptySet, reachable, {}), same(reachable));
         expect(reachable.restrict(h, emptySet, unreachable, {}),
             same(unreachable));
