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KT-2223 Comparing non-null value with null might produce helpful warning

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#KT-2223 Fixed
This commit is contained in:
Alexander Udalov
2012-06-20 17:20:45 +04:00
parent aed160e02a
commit d67e22b174
12 changed files with 92 additions and 46 deletions
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compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/autocasts/DataFlowInfo.java
+1 -1
View File
@@ -64,7 +64,7 @@ public class DataFlowInfo {
}
@NotNull
private Nullability getNullability(@NotNull DataFlowValue a) {
public Nullability getNullability(@NotNull DataFlowValue a) {
if (!a.isStableIdentifier()) return a.getImmanentNullability();
Nullability nullability = nullabilityInfo.get(a);
if (nullability == null) {
compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/BasicExpressionTypingVisitor.java
+32 -10
View File
@@ -35,6 +35,7 @@ import org.jetbrains.jet.lang.resolve.calls.OverloadResolutionResultsUtil;
import org.jetbrains.jet.lang.resolve.calls.autocasts.DataFlowInfo;
import org.jetbrains.jet.lang.resolve.calls.autocasts.DataFlowValue;
import org.jetbrains.jet.lang.resolve.calls.autocasts.DataFlowValueFactory;
import org.jetbrains.jet.lang.resolve.calls.autocasts.Nullability;
import org.jetbrains.jet.lang.resolve.constants.*;
import org.jetbrains.jet.lang.resolve.constants.StringValue;
import org.jetbrains.jet.lang.resolve.name.LabelName;
@@ -1036,29 +1037,50 @@ public class BasicExpressionTypingVisitor extends ExpressionTypingVisitor {
}
private void ensureNonemptyIntersectionOfOperandTypes(JetBinaryExpression expression, ExpressionTypingContext context) {
JetSimpleNameExpression operationSign = expression.getOperationReference();
JetExpression left = expression.getLeft();
JetExpression right = expression.getRight();
// TODO : duplicated effort for == and !=
JetType leftType = facade.getTypeInfo(left, context.replaceScope(context.scope)).getType();
JetType leftType = facade.getTypeInfo(left, context).getType();
if (leftType != null && right != null) {
JetType rightType = facade.getTypeInfo(right, context.replaceScope(context.scope)).getType();
JetType rightType = facade.getTypeInfo(right, context).getType();
if (rightType != null) {
if (TypeUtils.isIntersectionEmpty(leftType, rightType)) {
context.trace.report(EQUALITY_NOT_APPLICABLE.on(expression, operationSign, leftType, rightType));
context.trace.report(EQUALITY_NOT_APPLICABLE.on(expression, expression.getOperationReference(), leftType, rightType));
}
}
if (isSenselessComparisonWithNull(leftType, right) || isSenselessComparisonWithNull(rightType, left)) {
context.trace.report(SENSELESS_COMPARISON.on(expression, expression, operationSign.getReferencedNameElementType() == JetTokens.EXCLEQ));
checkSenselessComparisonWithNull(expression, left, right, context);
}
}
}
private boolean isSenselessComparisonWithNull(@Nullable JetType firstType, @NotNull JetExpression secondExpression) {
if (firstType == null) return false;
return !firstType.isNullable() && secondExpression instanceof JetConstantExpression && secondExpression.getNode().getElementType() == JetNodeTypes.NULL;
private void checkSenselessComparisonWithNull(@NotNull JetBinaryExpression expression, @NotNull JetExpression left, @NotNull JetExpression right, @NotNull ExpressionTypingContext context) {
JetExpression expr;
if (left instanceof JetConstantExpression && left.getNode().getElementType() == JetNodeTypes.NULL) {
expr = right;
}
else if (right instanceof JetConstantExpression && right.getNode().getElementType() == JetNodeTypes.NULL) {
expr = left;
}
else return;
JetSimpleNameExpression operationSign = expression.getOperationReference();
JetType type = facade.getTypeInfo(expr, context).getType();
DataFlowValue value = DataFlowValueFactory.INSTANCE.createDataFlowValue(expr, type, context.trace.getBindingContext());
Nullability nullability = context.dataFlowInfo.getNullability(value);
boolean expressionIsAlways;
boolean equality = operationSign.getReferencedNameElementType() == JetTokens.EQEQ || operationSign.getReferencedNameElementType() == JetTokens.EQEQEQ;
if (nullability == Nullability.NULL) {
expressionIsAlways = equality;
}
else if (nullability == Nullability.NOT_NULL) {
expressionIsAlways = !equality;
}
else return;
context.trace.report(SENSELESS_COMPARISON.on(expression, expression, expressionIsAlways));
}
protected JetType visitAssignmentOperation(JetBinaryExpression expression, ExpressionTypingContext context) {