Try-with-resource support: variable usage inspection

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting7/TryWithResourcesWarn.java

@@ -0,0 +1,51 @@
+import java.lang.Exception;
+
+class C {
+  static class MyResource implements AutoCloseable {
+    @Override public void close() { }
+  }
+
+  void m1() throws Exception {
+    MyResource r1;
+    try (r1 = new MyResource()) {
+      System.out.println(r1);
+    }
+
+    try (MyResource r2 = new MyResource()) {
+      System.out.println(r2);
+    }
+
+    MyResource r3 = new MyResource();
+    try (MyResource r = r3) {
+      System.out.println(r);
+    }
+  }
+
+  void m2() throws Exception {
+    MyResource r1 = <warning descr="Variable 'r1' initializer 'null'  is redundant">null</warning>;
+    try (r1 = new MyResource()) {
+      System.out.println(r1);
+    }
+
+    try (MyResource r2 = <warning descr="Variable 'r2' initializer 'new MyResource()'  is redundant">new MyResource()</warning>) {
+      r2 = null;  // todo: check for NPE
+      System.out.println(r2);
+    }
+
+    MyResource r3 = null;
+    System.out.println(r3);
+    try (r3 = <warning descr="The value 'new MyResource()' assigned to r3  is never used">new MyResource()</warning>) { }
+
+    try (MyResource <warning descr="Variable 'r4' is never used">r4</warning> = new MyResource()) { }
+
+    try (MyResource r5 = new MyResource()) {
+      System.out.println(r5);
+      r5 = <warning descr="The value 'new MyResource()' assigned to r5  is never used">new MyResource()</warning>;
+    }
+
+    MyResource <warning descr="Variable 'r6' is never assigned">r6</warning>;
+    try (MyResource r = <error descr="Variable 'r6' might not have been initialized">r6</error>) {
+      System.out.println(r);
+    }
+  }
+}