Mark getters, that return null only in case of parsing error

idea/src/org/jetbrains/jet/JetNodeTypes.java

@@ -34,6 +34,7 @@ public interface JetNodeTypes {
     // TODO: Not sure if we really need separate PSI nodes for the class parameters?
     JetNodeType PRIMARY_CONSTRUCTOR_PARAMETERS_LIST = new JetNodeType("PRIMARY_CONSTRUCTOR_PARAMETERS_LIST", JetParameterList.class);
     JetNodeType PRIMARY_CONSTRUCTOR_PARAMETER       = new JetNodeType("PRIMARY_CONSTRUCTOR_PARAMETER", JetParameter.class);
+
     JetNodeType CLASS_BODY                          = new JetNodeType("CLASS_BODY", JetClassBody.class);
     JetNodeType IMPORT_DIRECTIVE                    = new JetNodeType("IMPORT_DIRECTIVE", JetImportDirective.class);
     JetNodeType IMPORTED                            = new JetNodeType("IMPORTED"); // TODO: ???

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

@@ -17,11 +17,12 @@ public class JetArgument extends JetElement {
         visitor.visitArgument(this);
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetExpression getArgumentExpression() {
         return findChildByClass(JetExpression.class);
     }
 
+    @Nullable
     public String getArgumentName() {
         ASTNode firstChildNode = getNode().getFirstChildNode();
         return firstChildNode.getElementType() == JetTokens.IDENTIFIER ? firstChildNode.getText() : null;

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

@@ -21,7 +21,7 @@ public class JetAttribute extends JetElement {
         visitor.visitAttribute(this);
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetTypeReference getTypeReference() {
         return (JetTypeReference) findChildByType(JetNodeTypes.TYPE_REFERENCE);
     }

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

@@ -27,7 +27,7 @@ public class JetBinaryExpression extends JetExpression {
         return left;
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetExpression getRight() {
         ASTNode node = getOperationTokenNode();
         while (node != null) {
@@ -48,7 +48,7 @@ public class JetBinaryExpression extends JetExpression {
         return operationNode;
     }
 
-    @Nullable
+    @NotNull
     public JetToken getOperationSign() {
         return (JetToken) getOperationTokenNode().getElementType();
     }

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

@@ -27,7 +27,7 @@ public class JetBinaryExpressionWithTypeRHS extends JetExpression {
         return left;
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetTypeReference getRight() {
         ASTNode node = getOperationTokenNode();
         while (node != null) {
@@ -48,7 +48,7 @@ public class JetBinaryExpressionWithTypeRHS extends JetExpression {
         return operationNode;
     }
 
-    @Nullable
+    @NotNull
     public JetToken getOperationSign() {
         return (JetToken) getOperationTokenNode().getElementType();
     }

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

@@ -20,12 +20,12 @@ public class JetCatchSection extends JetElement {
         visitor.visitCatchSection(this);
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetParameterList getParameterList() {
         return (JetParameterList) findChildByType(JetNodeTypes.VALUE_PARAMETER_LIST);
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetParameter getCatchParameter() {
         JetParameterList list = getParameterList();
         if (list == null) return null;
@@ -34,6 +34,7 @@ public class JetCatchSection extends JetElement {
     }
 
 
+    @Nullable(IF_NOT_PARSED)
     public JetExpression getCatchBody() {
         return findChildByClass(JetExpression.class);
     }

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

@@ -2,7 +2,6 @@ package org.jetbrains.jet.lang.psi;
 
 import com.intellij.lang.ASTNode;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 /**
  * @author max
@@ -17,8 +16,10 @@ public class JetClassInitializer extends JetDeclaration {
         visitor.visitAnonymousInitializer(this);
     }
 
-    @Nullable
+    @NotNull
     public JetExpression getBody() {
-        return findChildByClass(JetExpression.class);
+        JetExpression body = findChildByClass(JetExpression.class);
+        assert body != null;
+        return body;
     }
 }

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

@@ -21,7 +21,7 @@ public class JetConstructor extends JetDeclaration {
         visitor.visitConstructor(this);
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetParameterList getParameterList() {
         return (JetParameterList) findChildByType(JetNodeTypes.VALUE_PARAMETER_LIST);
     }

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

@@ -21,7 +21,7 @@ public class JetDecomposer extends JetNamedDeclaration {
         visitor.visitDecomposer(this);
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetDecomposerPropertyList getPropertyList() {
         return (JetDecomposerPropertyList) findChildByType(JetNodeTypes.DECOMPOSER_PROPERTY_LIST);
     }

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

@@ -18,11 +18,12 @@ public class JetDoWhileExpression extends JetExpression {
         visitor.visitDoWhileExpression(this);
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetExpression getCondition() {
         return findExpressionUnder(JetNodeTypes.CONDITION);
     }
 
+    @Nullable(IF_NOT_PARSED)
     public JetExpression getBody() {
         return findExpressionUnder(JetNodeTypes.BODY);
     }

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

@@ -15,6 +15,8 @@ public class JetElement extends ASTWrapperPsiElement {
         super(node);
     }
 
+    protected static final String IF_NOT_PARSED = "Returns null if has parsing error";
+
     @NotNull
     @Override
     public Language getLanguage() {

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

@@ -21,6 +21,7 @@ public class JetExtension extends JetTypeParameterListOwner {
         visitor.visitExtension(this);
     }
 
+    @NotNull
     public List<JetDeclaration> getDeclarations() {
         JetClassBody body = (JetClassBody) findChildByType(JetNodeTypes.CLASS_BODY);
         if (body == null) return Collections.emptyList();
@@ -28,7 +29,7 @@ public class JetExtension extends JetTypeParameterListOwner {
         return body.getDeclarations();
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetTypeReference getTargetTypeRef() {
         return (JetTypeReference) findChildByType(JetNodeTypes.TYPE_REFERENCE);
     }

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

@@ -24,7 +24,7 @@ public class JetFunction extends JetTypeParameterListOwner {
         visitor.visitFunction(this);
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetParameterList getParameterList() {
         return (JetParameterList) findChildByType(JetNodeTypes.VALUE_PARAMETER_LIST);
     }

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

@@ -18,15 +18,17 @@ public class JetIfExpression extends JetExpression {
         visitor.visitIfExpression(this);
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetExpression getCondition() {
         return findExpressionUnder(JetNodeTypes.CONDITION);
     }
 
+    @Nullable(IF_NOT_PARSED)
     public JetExpression getThen() {
         return findExpressionUnder(JetNodeTypes.THEN);
     }
 
+    @Nullable
     public JetExpression getElse() {
         return findExpressionUnder(JetNodeTypes.ELSE);
     }

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

@@ -19,6 +19,7 @@ public class JetImportDirective extends JetElement {
         visitor.visitImportDirective(this);
     }
 
+    @NotNull
     public String getImportedName() {
         StringBuilder answer = new StringBuilder();
         ASTNode childNode = getNode().getFirstChildNode();

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

@@ -25,7 +25,7 @@ public class JetMatchExpression extends JetExpression {
         return left;
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetMatchBlock getMatchBlock() {
         return (JetMatchBlock) findChildByType(JetNodeTypes.MATCH_BLOCK);
     }

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

@@ -21,6 +21,7 @@ public class JetNewExpression extends JetExpression {
         visitor.visitNewExpression(this);
     }
 
+    @Nullable(IF_NOT_PARSED)
     public JetTypeReference getTypeReference() {
         return (JetTypeReference) findChildByType(JetNodeTypes.TYPE_REFERENCE);
     }

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

@@ -35,6 +35,7 @@ public class JetObjectLiteralExpression extends JetExpression implements JetClas
     }
 
     @Override
+    @NotNull
     public List<JetDeclaration> getDeclarations() {
         JetClassBody body = (JetClassBody) findChildByType(JetNodeTypes.CLASS_BODY);
         if (body == null) return Collections.emptyList();

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

@@ -19,8 +19,11 @@ public class JetPostfixExpression extends JetExpression {
         visitor.visitPostfixExpression(this);
     }
 
+    @NotNull
     public JetExpression getBaseExpression() {
-        return findChildByClass(JetExpression.class);
+        JetExpression answer = findChildByClass(JetExpression.class);
+        assert answer != null;
+        return answer;
     }
 
     @NotNull

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

@@ -2,7 +2,6 @@ package org.jetbrains.jet.lang.psi;
 
 import com.intellij.lang.ASTNode;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lexer.JetToken;
 import org.jetbrains.jet.lexer.JetTokens;
 
@@ -19,8 +18,11 @@ public class JetPrefixExpression extends JetExpression {
         visitor.visitPrefixExpression(this);
     }
 
+    @NotNull
     public JetExpression getBaseExpression() {
-        return findChildByClass(JetExpression.class);
+        JetExpression answer = findChildByClass(JetExpression.class);
+        assert answer != null;
+        return answer;
     }
 
     @NotNull
@@ -30,7 +32,7 @@ public class JetPrefixExpression extends JetExpression {
         return operationNode;
     }
 
-    @Nullable
+    @NotNull
     public JetToken getOperationSign() {
         return (JetToken) getOperationTokenNode().getElementType();
     }

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

@@ -71,6 +71,7 @@ public class JetProperty extends JetNamedDeclaration {
         return null;
     }
 
+    @Nullable
     public JetPropertyAccessor getSetter() {
         for (JetPropertyAccessor accessor : getAccessors()) {
             if (accessor.isSetter()) return accessor;

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

@@ -22,7 +22,7 @@ public abstract class JetQualifiedExpression extends JetExpression {
         return left;
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetExpression getSelectorExpression() {
         ASTNode node = getOperationTokenNode();
         while (node != null) {
@@ -42,7 +42,7 @@ public abstract class JetQualifiedExpression extends JetExpression {
         return operationNode;
     }
 
-    @Nullable
+    @NotNull
     public JetToken getOperationSign() {
         return (JetToken) getOperationTokenNode().getElementType();
     }

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

@@ -17,7 +17,7 @@ public class JetThrowExpression extends JetExpression {
         visitor.visitThrowExpression(this);
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetExpression getThrownExpression() {
         return findChildByClass(JetExpression.class);
     }

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

@@ -25,7 +25,7 @@ public class JetTypeConstraint extends JetElement {
                 findChildByType(JetTokens.OBJECT_KEYWORD) != null;
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetTypeReference getSubjectTypeReference() {
         ASTNode node = getNode().getFirstChildNode();
         while (node != null) {
@@ -38,7 +38,7 @@ public class JetTypeConstraint extends JetElement {
         return null;
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetTypeReference getExtendsTypeReference() {
         boolean passedColon = false;
         ASTNode node = getNode().getFirstChildNode();

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

@@ -21,6 +21,7 @@ public class JetTypeParameterListOwner extends JetNamedDeclaration {
         return (JetTypeParameterList) findChildByType(JetNodeTypes.TYPE_PARAMETER_LIST);
     }
 
+    @NotNull
     public List<JetTypeParameter> getTypeParameters() {
         JetTypeParameterList list = getTypeParameterList();
         if (list == null) return Collections.emptyList();

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

@@ -18,7 +18,7 @@ public class JetTypedef extends JetTypeParameterListOwner {
         visitor.visitTypedef(this);
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetTypeReference getTypeReference() {
         return (JetTypeReference) findChildByType(JetNodeTypes.TYPE_REFERENCE);
     }

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

@@ -18,11 +18,12 @@ public class JetWhileExpression extends JetExpression {
         visitor.visitWhileExpression(this);
     }
 
-    @Nullable
+    @Nullable(IF_NOT_PARSED)
     public JetExpression getCondition() {
         return findExpressionUnder(JetNodeTypes.CONDITION);
     }
 
+    @Nullable(IF_NOT_PARSED)
     public JetExpression getBody() {
         return findExpressionUnder(JetNodeTypes.BODY);
     }

idea/tests/org/jetbrains/jet/parsing/JetParsingTest.java

@@ -4,22 +4,24 @@
 package org.jetbrains.jet.parsing;
 
 import com.intellij.openapi.application.PathManager;
+import com.intellij.psi.PsiErrorElement;
 import com.intellij.psi.PsiFile;
+import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.testFramework.ParsingTestCase;
 import junit.framework.TestSuite;
 import org.jetbrains.annotations.NonNls;
+import org.jetbrains.jet.lang.psi.JetBinaryExpression;
 import org.jetbrains.jet.lang.psi.JetElement;
+import org.jetbrains.jet.lang.psi.JetExpression;
 import org.jetbrains.jet.lang.psi.JetVisitor;
 
 import java.io.File;
 import java.io.FileFilter;
 import java.io.FilenameFilter;
 import java.io.IOException;
-import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.Comparator;
 import java.util.List;
 
 public class JetParsingTest extends ParsingTestCase {
@@ -49,7 +51,6 @@ public class JetParsingTest extends ParsingTestCase {
 
     @Override
     protected void checkResult(@NonNls String targetDataName, PsiFile file) throws IOException {
-        super.checkResult(targetDataName, file);
         file.acceptChildren(new JetVisitor() {
             @Override
             public void visitJetElement(JetElement elem) {
@@ -60,7 +61,20 @@ public class JetParsingTest extends ParsingTestCase {
                     throw new RuntimeException(throwable);
                 }
             }
+
+            @Override
+            public void visitBinaryExpression(JetBinaryExpression expression) {
+                super.visitBinaryExpression(expression);
+                JetExpression right = expression.getRight();
+                JetExpression left = expression.getLeft();
+                assertNotSame(left, right);
+                if (right == null) {
+                    assertNotNull("Imcomplete binary operation in parsed OK test", PsiTreeUtil.findChildOfType(expression, PsiErrorElement.class) != null);
+                }
+            }
         });
+
+        super.checkResult(targetDataName, file);
     }
 
     private void checkPsiGetters(JetElement elem) throws Throwable {