Issue 4795. Fix for if-as-then-assign-else

compiler/javatests/com/google/dart/compiler/type/TypeAnalyzerCompilerTest.java

Index: compiler/javatests/com/google/dart/compiler/type/TypeAnalyzerCompilerTest.java
diff --git a/compiler/javatests/com/google/dart/compiler/type/TypeAnalyzerCompilerTest.java b/compiler/javatests/com/google/dart/compiler/type/TypeAnalyzerCompilerTest.java
index 069c466f4469697f3d8b029be942f003e6e4b4aa..e7f5be730e0595d761fdc891aaea9c73c9957020 100644
--- a/compiler/javatests/com/google/dart/compiler/type/TypeAnalyzerCompilerTest.java
+++ b/compiler/javatests/com/google/dart/compiler/type/TypeAnalyzerCompilerTest.java
@@ -42,7 +42,6 @@ import com.google.dart.compiler.ast.DartUnqualifiedInvocation;
 import com.google.dart.compiler.common.SourceInfo;
 import com.google.dart.compiler.parser.ParserErrorCode;
 import com.google.dart.compiler.resolver.ClassElement;
-import com.google.dart.compiler.resolver.ClassNodeElement;
 import com.google.dart.compiler.resolver.Element;
 import com.google.dart.compiler.resolver.ElementKind;
 import com.google.dart.compiler.resolver.MethodElement;
@@ -2050,6 +2049,24 @@ public class TypeAnalyzerCompilerTest extends CompilerTestCase {
     assertInferredElementTypeString(testUnit, "d1", "bool");
   }
 
+  public void test_typesPropagation_multiAssign_IfThenElse_whenAsTypeCondition() throws Exception {
+    analyzeLibrary(
+        "// filler filler filler filler filler filler filler filler filler filler",
+        "f(var v) {",
+        "  if (v is String) {",
+        "    var v1 = v;",
+        "    v = null;",
+        "  } else {",
+        "    var v2 = v;",
+        "  }",
+        "  var v3 = v;",
+        "}",
+        "");
+    assertInferredElementTypeString(testUnit, "v1", "String");
+    assertInferredElementTypeString(testUnit, "v2", "Dynamic");
+    assertInferredElementTypeString(testUnit, "v3", "Dynamic");
+  }
+
   public void test_typesPropagation_multiAssign_While() throws Exception {
     analyzeLibrary(
         "// filler filler filler filler filler filler filler filler filler filler",