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  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
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  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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  23 
  24 /*
  25  * @test
  26  * @bug 8223305 8226522
  27  * @summary Ensure proper errors are returned for yields.
  28  * @compile/fail/ref=WrongYieldTest.out -XDrawDiagnostics -XDshould-stop.at=ATTR WrongYieldTest.java
  29  */
  30 
  31 package t;
  32 
  33 //ERROR - type called yield:
  34 import t.WrongYieldTest.yield;
  35 
  36 public class WrongYieldTest {
  37 
  38     // ERROR -  class called yield
  39     class yield { }
  40 
  41     // OK to have fields called yield
  42     String[] yield = null;
  43 
  44     // ERROR - field of type yield
  45     yield y;
  46 
  47     // OK to have methods called yield
  48     // Nullary yield method
  49     String[] yield() {
  50         return null;
  51     }
  52     // Unary yield method
  53     String[] yield(int i) {
  54         return null;
  55     }
  56     // Binary yield method
  57     String[] yield(int i, int j) {
  58         return null;
  59     }
  60 
  61     // OK to declare a local called yield
  62     void LocalDeclaration1() {
  63        int yield;
  64     }
  65     // OK to declare and initialise a local called yield
  66     void LocalDeclaration2() {
  67         int yield = 42;
  68     }
  69     // ERROR can't refer to a local called yield in the initialiser
  70     void LocalDeclaration3() {
  71         int yield = yield + 1;
  72     }
  73 
  74     // OK yield gets interpreted as an identifier in a local declaration
  75     void LocalDeclaration4(int i) {
  76         int local = switch (i) {
  77             default -> {
  78                 int yield = yield + 1;
  79                 yield 42;
  80             }
  81         };
  82     }
  83     // OK - yield a local called yield
  84     void LocalDeclaration5(int i) {
  85         int yield = 42;
  86         int temp = switch (i) {
  87             default -> {
  88                 yield yield;
  89             }
  90         };
  91     }
  92 
  93     void YieldTypedLocals(int i) {
  94         // ERROR - Parsed as yield statement, and y1 is unknown
  95         yield y1 = null;
  96         // ..whereas..
  97         // ERROR - parsed as yield statement, which has no switch target
  98         Object y1;
  99         yield y1 = null;
 100 
 101         // ERROR - Parsed as yield statement, and y2 is unknown
 102         yield y2 = new yield();
 103 
 104         // OK - Parsed as yield statement that assigns local y
 105         Object y;
 106         Object o = switch (i) {
 107             default :
 108                 yield y = null;
 109         };
 110 
 111         // ERROR - Parsed as yield statement that assigns local y,
 112         //but the initializer refers to restricted identifier:
 113         Object y2;
 114         Object o2 = switch (i) {
 115             default :
 116                 yield y2 = new yield();
 117         };
 118 
 119         // ERROR - can not create an yield-valued local of type Object
 120         Object y3 = new yield();
 121 
 122         // ERROR - can not create a final yield-valued local of type yield
 123         final yield y4 = new yield();
 124 
 125         // ERROR - can create a non-final local of type yield using qualified typename
 126         WrongYieldTest.yield y5 = new yield();
 127 
 128     }
 129 
 130     void MethodInvocation(int i) {
 131 
 132         // OK - can access a field called yield
 133         String[] x = this.yield;
 134 
 135         // ERROR - calling nullary yield method using simple name parsed as yield statement
 136         yield();
 137         // OK - can call nullary yield method using qualified name
 138         this.yield();
 139 
 140         // ERROR - Calling unary yield method using simple name is parsed as yield statement
 141         yield(2);
 142         // OK - calling unary yield method using qualified name
 143         this.yield(2);
 144 
 145         // ERROR - Calling binary yield method using simple name is parsed as yield statement
 146         yield(2, 2); //error
 147         // OK - calling binary yield method using qualified name
 148         this.yield(2, 2);
 149 
 150         // ERROR - nullary yield method as receiver is parsed as yield statement
 151         yield().toString();
 152         // OK - nullary yield method as receiver using qualified name
 153         this.yield().toString();
 154 
 155         // ERROR - unary yield method as receiver is parsed as yield statement
 156         yield(2).toString();
 157         // OK - unary yield method as receiver using qualified name
 158         this.yield(2).toString();
 159 
 160         // ERROR - binary yield method as receiver is parsed as yield statement
 161         yield(2, 2).toString();
 162         // OK - binary yield method as receiver using qualified name
 163         this.yield(2, 2).toString();
 164 
 165         // OK - yield method call is in an expression position
 166         String str = yield(2).toString();
 167 
 168 
 169 
 170         //OK - yield is a variable
 171         yield.toString();
 172 
 173         // OK - parsed as method call (with qualified local yield as receiver)
 174         this.yield.toString();
 175 
 176         yield[0].toString(); //error
 177 
 178         // OK - parsed as yield statement in switch expression
 179         int j = switch (i) {
 180             default:
 181                 yield(2);
 182         };
 183 
 184         // ERROR - second yield is an unreachable statement.
 185         x = switch (i) {
 186             default: {
 187                 yield x = null;
 188                 yield null;
 189             }
 190         };
 191     }
 192 
 193     private void yieldLocalVar1(int i) {
 194         int yield = 0;
 195 
 196         //OK - yield is a variable:
 197         yield++;
 198         yield--;
 199 
 200         //ERROR - yield is a statement, but no enclosing switch expr:
 201         yield ++i;
 202         yield --i;
 203 
 204         //OK - yield is a variable:
 205         yield = 3;
 206 
 207         //OK - yield is a variable:
 208         for (int j = 0; j < 3; j++)
 209             yield += 1;
 210 
 211         //OK - yield is a variable and not at the beginning of the statement:
 212         yieldLocalVar1(yield);
 213 
 214         //ERROR - unqualified yield method invocation:
 215         yieldLocalVar1(yield().length);
 216         yieldLocalVar1(yield.class.getModifiers());
 217     }
 218 
 219     private void yieldLocalVar2(int i) {
 220         int[] yield = new int[1];
 221 
 222         //OK - yield is a variable:
 223         yield[0] = 5;
 224     }
 225 
 226     private void lambda() {
 227         SAM s = (yield y) -> {};
 228     }
 229 
 230     interface SAM {
 231         public void m(Object o);
 232     }
 233 }