Fixed the typechecking for try..catch

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

@@ -75,6 +75,7 @@ public class JetTypeChecker {
         boolean nullable = false;
         for (Iterator<JetType> iterator = typeSet.iterator(); iterator.hasNext();) {
             JetType type = iterator.next();
+            assert type != null;
             // TODO : This admits 'Nothing?'. Review
             if (JetStandardClasses.isNothing(type)) {
                 iterator.remove();

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

@@ -959,19 +959,38 @@ public class JetTypeInferrer {
             List<JetCatchClause> catchClauses = expression.getCatchClauses();
             JetFinallySection finallyBlock = expression.getFinallyBlock();
             List<JetType> types = new ArrayList<JetType>();
-            if (finallyBlock == null) {
-                for (JetCatchClause catchClause : catchClauses) {
-                    // TODO: change scope here
-                    JetExpression catchBody = catchClause.getCatchBody();
+            for (JetCatchClause catchClause : catchClauses) {
+                JetParameter catchParameter = catchClause.getCatchParameter();
+                JetExpression catchBody = catchClause.getCatchBody();
+                if (catchParameter != null) {
+                    VariableDescriptor variableDescriptor = classDescriptorResolver.resolveLocalVariableDescriptor(scope.getContainingDeclaration(), scope, catchParameter);
                     if (catchBody != null) {
-                        types.add(getType(scope, catchBody, true));
+                        WritableScope catchScope = semanticServices.createWritableScope(scope, scope.getContainingDeclaration());
+                        catchScope.addVariableDescriptor(variableDescriptor);
+                        JetType type = getType(catchScope, catchBody, true);
+                        if (type != null) {
+                            types.add(type);
+                        }
                     }
                 }
-            } else {
-                types.add(getType(scope, finallyBlock.getFinalExpression(), true));
             }
-            types.add(getType(scope, tryBlock, true));
-            result = semanticServices.getTypeChecker().commonSupertype(types);
+            if (finallyBlock != null) {
+                types.clear(); // Do not need the list for the check, but need the code above to typecheck catch bodies
+                JetType type = getType(scope, finallyBlock.getFinalExpression(), true);
+                if (type != null) {
+                    types.add(type);
+                }
+            }
+            JetType type = getType(scope, tryBlock, true);
+            if (type != null) {
+                types.add(type);
+            }
+            if (types.isEmpty()) {
+                result = null;
+            }
+            else {
+                result = semanticServices.getTypeChecker().commonSupertype(types);
+            }
         }
 
         @Override

idea/testData/resolve/TryCatch.jet

@@ -0,0 +1,21 @@
+fun test() {
+    ~x~val x = 1
+    try {
+      ~y~val y = `x`x
+    }
+    catch (~e1~e : Exception) {
+      val z = `e1`e
+      val zz = `!`y
+      val zzz = `x`x
+    }
+    catch (~e2~e : Exception) {
+      val z = `e2`e
+      val zz = `!`y
+      val zzz = `x`x
+    }
+    finally {
+      val z = `!`e
+      val zz = `!`y
+      val zzz = `x`x
+    }
+}

idea/tests/org/jetbrains/jet/resolve/JetResolveTest.java

@@ -151,4 +151,8 @@ public class JetResolveTest extends ExtensibleResolveTestCase {
         doTest("/resolve/Namespaces.jet", true, true);
     }
 
+    public void testTryCatch() throws Exception {
+        doTest("/resolve/TryCatch.jet", true, true);
+    }
+
 }