If an if or do statement always exits, following statements are dead.

pkg/analyzer/test/generated/hint_code_test.dart

Index: pkg/analyzer/test/generated/hint_code_test.dart
diff --git a/pkg/analyzer/test/generated/hint_code_test.dart b/pkg/analyzer/test/generated/hint_code_test.dart
index 39752705c06ccf3780e8a592c3452bb3a52d2117..043faeb754265b75a685958b22fc5f4fdc00f2a7 100644
--- a/pkg/analyzer/test/generated/hint_code_test.dart
+++ b/pkg/analyzer/test/generated/hint_code_test.dart
@@ -21,7 +21,7 @@ main() {
 
 @reflectiveTest
 class HintCodeTest extends ResolverTestCase {
-  void fail_deadCode_statementAfterRehrow() {
+  void test_deadCode_statementAfterRethrow() {
     Source source = addSource(r'''
 f() {
   try {
@@ -36,7 +36,7 @@ f() {
     verify([source]);
   }
 
-  void fail_deadCode_statementAfterThrow() {
+  void test_deadCode_statementAfterThrow() {
     Source source = addSource(r'''
 f() {
   var one = 1;
@@ -619,6 +619,21 @@ f() {
     verify([source]);
   }
 
+  void test_deadCode_statementAfterExitingIf_returns() {
+    Source source = addSource(r'''
+f() {
+  if (1 > 2) {
+    return;
+  } else {
+    return;
+  }
+  var one = 1;
+}''');
+    computeLibrarySourceErrors(source);
+    assertErrors(source, [HintCode.DEAD_CODE]);
+    verify([source]);
+  }
+
   void test_deprecatedAnnotationUse_assignment() {
     Source source = addSource(r'''
 class A {