src/share/classes/com/sun/tools/javac/comp/Flow.java

*** 35,44 ****
--- 35,47 ----
  import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
  
  import com.sun.tools.javac.code.Symbol.*;
  import com.sun.tools.javac.tree.JCTree.*;
  
+ import java.util.HashSet;
+ import java.util.Set;
+ 
  import static com.sun.tools.javac.code.Flags.*;
  import static com.sun.tools.javac.code.Kinds.*;
  import static com.sun.tools.javac.code.TypeTags.*;
  
  /** This pass implements dataflow analysis for Java programs.
*** 263,272 ****
--- 266,279 ----
      /** The list of exceptions that are either caught or declared to be
       *  thrown.
       */
      List<Type> caught;
  
+     /** The list of unreferenced automatic resources.
+      */
+     Set<VarSymbol> unrefdResources;
+ 
      /** Set when processing a loop body the second time for DU analysis. */
      boolean loopPassTwo = false;
  
      /*-------------------- Environments ----------------------*/
  
*** 961,970 ****
--- 968,978 ----
          }
  
      public void visitTry(JCTry tree) {
          List<Type> caughtPrev = caught;
          List<Type> thrownPrev = thrown;
+         Set<VarSymbol> unrefdResourcesPrev = unrefdResources;
          thrown = List.nil();
          for (List<JCCatch> l = tree.catchers; l.nonEmpty(); l = l.tail) {
              List<JCExpression> subClauses = TreeInfo.isMultiCatch(l.head) ?
                      ((JCTypeDisjoint)l.head.param.vartype).components :
                      List.of(l.head.param.vartype);
*** 975,994 ****
--- 983,1036 ----
          Bits uninitsTryPrev = uninitsTry;
          ListBuffer<PendingExit> prevPendingExits = pendingExits;
          pendingExits = new ListBuffer<PendingExit>();
          Bits initsTry = inits.dup();
          uninitsTry = uninits.dup();
+         unrefdResources = new HashSet<VarSymbol>();
+         for (JCTree resource : tree.resources) {
+             if (resource instanceof JCVariableDecl) {
+                 JCVariableDecl vdecl = (JCVariableDecl) resource;
+                 visitVarDef(vdecl);
+                 unrefdResources.add(vdecl.sym);
+             } else if (resource instanceof JCExpression) {
+                 scanExpr((JCExpression) resource);
+             } else {
+                 throw new AssertionError(tree);  // parser error
+             }
+         }
+         for (JCTree resource : tree.resources) {
+             MethodSymbol topCloseMethod = (MethodSymbol)syms.autoCloseableType.tsym.members().lookup(names.close).sym;
+             List<Type> closeableSupertypes = resource.type.isCompound() ?
+                 types.interfaces(resource.type).prepend(types.supertype(resource.type)) :
+                 List.of(resource.type);
+             for (Type sup : closeableSupertypes) {
+                 if (types.asSuper(sup, syms.autoCloseableType.tsym) != null) {
+                     MethodSymbol closeMethod = types.implementation(topCloseMethod, sup.tsym, types, true);
+                     for (Type t : closeMethod.getThrownTypes()) {
+                         markThrown(tree.body, t);
+                     }
+                 }
+             }
+         }
          scanStat(tree.body);
          List<Type> thrownInTry = thrown;
          thrown = thrownPrev;
          caught = caughtPrev;
          boolean aliveEnd = alive;
          uninitsTry.andSet(uninits);
          Bits initsEnd = inits;
          Bits uninitsEnd = uninits;
          int nextadrCatch = nextadr;
  
+         if (!unrefdResources.isEmpty() &&
+                 lint.isEnabled(Lint.LintCategory.ARM)) {
+             for (VarSymbol v : unrefdResources) {
+                 log.warning(v.pos,
+                             "automatic.resource.not.referenced", v);
+             }
+         }
+ 
          List<Type> caughtInTry = List.nil();
          for (List<JCCatch> l = tree.catchers; l.nonEmpty(); l = l.tail) {
              alive = true;
              JCVariableDecl param = l.head.param;
              List<JCExpression> subClauses = TreeInfo.isMultiCatch(l.head) ?
*** 1068,1077 ****
--- 1110,1120 ----
              ListBuffer<PendingExit> exits = pendingExits;
              pendingExits = prevPendingExits;
              while (exits.nonEmpty()) pendingExits.append(exits.next());
          }
          uninitsTry.andSet(uninitsTryPrev).andSet(uninits);
+         unrefdResources = unrefdResourcesPrev;
      }
  
      public void visitConditional(JCConditional tree) {
          scanCond(tree.cond);
          Bits initsBeforeElse = initsWhenFalse;
*** 1291,1302 ****
          // annotations don't get scanned
          tree.underlyingType.accept(this);
      }
  
      public void visitIdent(JCIdent tree) {
!         if (tree.sym.kind == VAR)
              checkInit(tree.pos(), (VarSymbol)tree.sym);
      }
  
      public void visitTypeCast(JCTypeCast tree) {
          super.visitTypeCast(tree);
          if (!tree.type.isErroneous()
--- 1334,1353 ----
          // annotations don't get scanned
          tree.underlyingType.accept(this);
      }
  
      public void visitIdent(JCIdent tree) {
!         if (tree.sym.kind == VAR) {
              checkInit(tree.pos(), (VarSymbol)tree.sym);
+             referenced(tree.sym);
+         }
+     }
+ 
+     void referenced(Symbol sym) {
+         if (unrefdResources != null && unrefdResources.contains(sym)) {
+             unrefdResources.remove(sym);
+         }
      }
  
      public void visitTypeCast(JCTypeCast tree) {
          super.visitTypeCast(tree);
          if (!tree.type.isErroneous()