Multiple conditions in when entries

idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java

@@ -1774,7 +1774,9 @@ public class ExpressionCodegen extends JetVisitor {
             }
             nextEntry = new Label();
             if (!whenEntry.isElse()) {
-                JetWhenCondition condition = whenEntry.getCondition();
+                JetWhenCondition[] conditions = whenEntry.getConditions();
+                assert conditions.length == 1 : "Support many conditions"; // TODO
+                JetWhenCondition condition = conditions[0];
                 StackValue conditionValue;
                 if (condition instanceof JetWhenConditionWithExpression) {
                     v.load(subjectLocal, subjectType);

idea/src/org/jetbrains/jet/lang/cfg/JetControlFlowProcessor.java

@@ -640,8 +640,11 @@ public class JetControlFlowProcessor {
                     }
                 }
 
-                JetWhenCondition condition = whenEntry.getCondition();
-                if (condition != null) {
+                Label bodyLabel = builder.createUnboundLabel();
+
+                JetWhenCondition[] conditions = whenEntry.getConditions();
+                for (int i = 0; i < conditions.length; i++) {
+                    JetWhenCondition condition = conditions[i];
                     condition.accept(new JetVisitor() {
                         private final JetVisitor conditionVisitor = this;
 
@@ -714,10 +717,14 @@ public class JetControlFlowProcessor {
                             throw new UnsupportedOperationException("[JetControlFlowProcessor] " + element.toString());
                         }
                     });
+                    if (i + 1 < conditions.length) {
+                        builder.nondeterministicJump(bodyLabel);
+                    }
                 }
 
                 builder.nondeterministicJump(nextLabel);
 
+                builder.bindLabel(bodyLabel);
                 value(whenEntry.getExpression(), true, inCondition);
                 builder.jump(doneLabel);
                 builder.bindLabel(nextLabel);
@@ -771,4 +778,4 @@ public class JetControlFlowProcessor {
             // Nothing
         }
     };
-}
+}

idea/src/org/jetbrains/jet/lang/psi/JetWhenEntry.java

@@ -38,8 +38,8 @@ public class JetWhenEntry extends JetElement {
         visitor.visitWhenEntry(this);
     }
 
-    @Nullable
-    public JetWhenCondition getCondition() {
-        return findChildByClass(JetWhenCondition.class);
+    @NotNull
+    public JetWhenCondition[] getConditions() {
+        return findChildrenByClass(JetWhenCondition.class);
     }
 }

idea/src/org/jetbrains/jet/lang/types/JetTypeInferrer.java

@@ -764,7 +764,7 @@ public class JetTypeInferrer {
             return getTypeWithNewContext(expression, new TypeInferenceContext(context.trace, scope, preferBlock, context.dataFlowInfo, context.expectedType, context.expectedReturnType));
         }
 
-        private JetType getTypeWithNewDataFlowInfo(JetScope scope, JetExpression expression, boolean preferBlock, DataFlowInfo newDataFlowInfo) {
+        private JetType getTypeWithNewDataFlowInfo(JetScope scope, JetExpression expression, boolean preferBlock, @NotNull DataFlowInfo newDataFlowInfo) {
             return getTypeWithNewContext(expression, new TypeInferenceContext(context.trace, scope, preferBlock, newDataFlowInfo, context.expectedType, context.expectedReturnType));
         }
 
@@ -1294,11 +1294,35 @@ public class JetTypeInferrer {
 
             Set<JetType> expressionTypes = Sets.newHashSet();
             for (JetWhenEntry whenEntry : expression.getEntries()) {
-                JetWhenCondition condition = whenEntry.getCondition();
-                WritableScope scopeToExtend = newWritableScopeImpl().setDebugName("Scope extended in when entry");
-                DataFlowInfo newDataFlowInfo = context.dataFlowInfo;
-                if (condition != null) {
-                    newDataFlowInfo = checkWhenCondition(subjectExpression, subjectType, condition, scopeToExtend, variableDescriptor);
+                JetWhenCondition[] conditions = whenEntry.getConditions();
+                DataFlowInfo newDataFlowInfo;
+                WritableScope scopeToExtend;
+                if (conditions.length == 1) {
+                    scopeToExtend = newWritableScopeImpl().setDebugName("Scope extended in when entry");
+                    newDataFlowInfo = context.dataFlowInfo;
+                    JetWhenCondition condition = conditions[0];
+                    if (condition != null) {
+                        newDataFlowInfo = checkWhenCondition(subjectExpression, subjectType, condition, scopeToExtend, variableDescriptor);
+                    }
+                }
+                else {
+                    scopeToExtend = newWritableScopeImpl(); // We don't write to this scope
+                    newDataFlowInfo = null;
+                    for (JetWhenCondition condition : conditions) {
+                        DataFlowInfo dataFlowInfo = checkWhenCondition(subjectExpression, subjectType, condition, newWritableScopeImpl(), variableDescriptor);
+                        if (newDataFlowInfo == null) {
+                            newDataFlowInfo = dataFlowInfo;
+                        }
+                        else {
+                            newDataFlowInfo = newDataFlowInfo.or(dataFlowInfo);
+                        }
+                    }
+                    if (newDataFlowInfo == null) {
+                        newDataFlowInfo = context.dataFlowInfo;
+                    }
+                    else {
+                        newDataFlowInfo = newDataFlowInfo.and(context.dataFlowInfo);
+                    }
                 }
                 JetWhenExpression subWhen = whenEntry.getSubWhen();
                 JetExpression bodyExpression = subWhen == null ? whenEntry.getExpression() : subWhen;

idea/testData/checker/regression/Jet169.jet

@@ -0,0 +1,8 @@
+fun set(key : String, value : String) {
+  val a : String? = ""
+  when (a) {
+    "" => a<error>.</error>get(0)
+    is String, is Any => a.compareTo("")
+    else => a.toString()
+  }
+}