Examples with VisitorState com.google.errorprone.VisitorState used on opensource projects

Example 11 with VisitorState

use of com.google.errorprone.VisitorState in project error-prone by google.

the class CompileTimeConstantExpressionMatcherTest method assertCompilerMatchesOnAssignment.

// Helper methods.
private void assertCompilerMatchesOnAssignment(final Map<String, Boolean> expectedMatches, String... lines) {
    final Matcher<ExpressionTree> matcher = new CompileTimeConstantExpressionMatcher();
    final Scanner scanner = new Scanner() {

        @Override
        public Void visitAssignment(AssignmentTree t, VisitorState state) {
            ExpressionTree lhs = t.getVariable();
            if (expectedMatches.containsKey(lhs.toString())) {
                boolean matches = matcher.matches(t.getExpression(), state);
                if (expectedMatches.get(lhs.toString())) {
                    assertTrue("Matcher should match expression" + t.getExpression(), matches);
                } else {
                    assertFalse("Matcher should not match expression" + t.getExpression(), matches);
                }
            }
            return super.visitAssignment(t, state);
        }
    };
    CompilationTestHelper.newInstance(ScannerSupplier.fromScanner(scanner), getClass()).expectResult(Result.OK).addSourceLines("test/CompileTimeConstantExpressionMatcherTestCase.java", lines).doTest();
}

Example 12 with VisitorState

use of com.google.errorprone.VisitorState in project error-prone by google.

the class ChainingConstructorIgnoresParameter method evaluateCallers.

private Description evaluateCallers(MethodSymbol symbol) {
    List<VariableTree> paramTypes = paramTypesForMethod.get(symbol);
    if (paramTypes == null) {
        // We haven't seen the declaration yet. We'll evaluate the call when we do.
        return NO_MATCH;
    }
    for (Caller caller : callersToEvaluate.removeAll(symbol)) {
        VisitorState state = caller.state;
        MethodInvocationTree invocation = caller.tree;
        MethodTree callerConstructor = state.findEnclosing(MethodTree.class);
        if (callerConstructor == null) {
            // impossible, at least in compilable code?
            continue;
        }
        Map<String, Type> availableParams = indexTypeByName(callerConstructor.getParameters());
        /*
       * TODO(cpovirk): Better handling of varargs: If the last parameter type is varargs and it is
       * called as varargs (rather than by passing an array), then rewrite the parameter types to
       * (p0, p1, ..., p[n-2], p[n-1] = element type of varargs parameter if an argument is
       * supplied, p[n] = ditto, etc.). For now, we settle for not crashing in the face of a
       * mismatch between the number of parameters declared and the number supplied.
       *
       * (Use MethodSymbol.isVarArgs.)
       */
        for (int i = 0; i < paramTypes.size() && i < invocation.getArguments().size(); i++) {
            VariableTree formalParam = paramTypes.get(i);
            String formalParamName = formalParam.getName().toString();
            Type formalParamType = getType(formalParam.getType());
            Type availableParamType = availableParams.get(formalParamName);
            ExpressionTree actualParam = invocation.getArguments().get(i);
            if (/*
             * The caller has no param of this type. (Or if it did, we couldn't determine the type.
             * Does that ever happen?) If the param doesn't exist, the caller can't be failing to
             * pass it.
             */
            availableParamType == null || /*
             * We couldn't determine the type of the formal parameter. (Does this ever happen?)
             */
            formalParamType == null || /*
             * The caller is passing the expected parameter (or "ImmutableList.copyOf(parameter),"
             * "new File(parameter)," etc.).
             */
            referencesIdentifierWithName(formalParamName, actualParam, state)) {
                continue;
            }
            if (state.getTypes().isAssignable(availableParamType, formalParamType)) {
                reportMatch(invocation, state, actualParam, formalParamName);
            }
        /*
         * If formal parameter is of an incompatible type, the caller might in theory still intend
         * to pass a dervied expression. For example, "Foo(String file)" might intend to call
         * "Foo(File file)" by passing "new File(file)." If this comes up in practice, we could
         * provide the dummy suggested fix "someExpression(formalParamName)." However, my research
         * suggests that this will rarely if ever be what the user wants.
         */
        }
    }
    // All matches are reported through reportMatch calls instead of return values.
    return NO_MATCH;
}

Example 13 with VisitorState

use of com.google.errorprone.VisitorState in project error-prone by google.

the class FunctionalInterfaceMethodChanged method matchMethod.

@Override
public Description matchMethod(MethodTree tree, VisitorState state) {
    ClassTree enclosingClazz = ASTHelpers.findEnclosingNode(state.getPath(), ClassTree.class);
    if (tree.getModifiers().getFlags().contains(Modifier.DEFAULT) && IS_FUNCTIONAL_INTERFACE.matches(enclosingClazz, state)) {
        Types types = Types.instance(state.context);
        Set<Symbol> functionalSuperInterfaceSams = enclosingClazz.getImplementsClause().stream().filter(t -> IS_FUNCTIONAL_INTERFACE.matches(t, state)).map(ASTHelpers::getSymbol).map(TypeSymbol.class::cast).map(// TypeSymbol to single abstract method of the type
        types::findDescriptorSymbol).collect(toImmutableSet());
        // We designate an override of a superinterface SAM "behavior preserving" if it just
        // calls the SAM of this interface.
        Symbol thisInterfaceSam = types.findDescriptorSymbol(ASTHelpers.getSymbol(enclosingClazz));
        // relatively crude: doesn't verify that the same args are passed in the same order
        // so it can get false positives for behavior-preservingness (false negatives for the check)
        TreeVisitor<Boolean, VisitorState> behaviorPreserving = new SimpleTreeVisitor<Boolean, VisitorState>(false) {

            @Override
            public Boolean visitMethod(MethodTree node, VisitorState state) {
                return node.getBody() != null && node.getBody().accept(this, state);
            }

            @Override
            public Boolean visitBlock(BlockTree node, VisitorState state) {
                return node.getStatements().size() == 1 && Iterables.getOnlyElement(node.getStatements()).accept(this, state);
            }

            @Override
            public Boolean visitExpressionStatement(ExpressionStatementTree node, VisitorState state) {
                return node.getExpression().accept(this, state);
            }

            @Override
            public Boolean visitReturn(ReturnTree node, VisitorState state) {
                return node.getExpression().accept(this, state);
            }

            @Override
            public Boolean visitMethodInvocation(MethodInvocationTree node, VisitorState state) {
                return ASTHelpers.getSymbol(node) == thisInterfaceSam;
            }
        };
        if (!Collections.disjoint(ASTHelpers.findSuperMethods(ASTHelpers.getSymbol(tree), types), functionalSuperInterfaceSams) && !tree.accept(behaviorPreserving, state)) {
            return describeMatch(tree);
        }
    }
    return Description.NO_MATCH;
}

Example 14 with VisitorState

use of com.google.errorprone.VisitorState in project error-prone by google.

the class MissingCasesInEnumSwitch method matchSwitch.

@Override
public Description matchSwitch(SwitchTree tree, VisitorState state) {
    Type switchType = ASTHelpers.getType(tree.getExpression());
    if (switchType.asElement().getKind() != ElementKind.ENUM) {
        return Description.NO_MATCH;
    }
    // default case is present
    if (tree.getCases().stream().anyMatch(c -> c.getExpression() == null)) {
        return Description.NO_MATCH;
    }
    ImmutableSet<String> handled = tree.getCases().stream().map(CaseTree::getExpression).filter(IdentifierTree.class::isInstance).map(e -> ((IdentifierTree) e).getName().toString()).collect(toImmutableSet());
    Set<String> unhandled = Sets.difference(ASTHelpers.enumValues(switchType.asElement()), handled);
    if (unhandled.isEmpty()) {
        return Description.NO_MATCH;
    }
    return buildDescription(tree).setMessage(buildMessage(unhandled)).build();
}

Example 15 with VisitorState

use of com.google.errorprone.VisitorState in project error-prone by google.

the class ComparisonContractViolated method matchMethod.

@Override
public Description matchMethod(MethodTree tree, VisitorState state) {
    if (tree.getBody() == null) {
        return Description.NO_MATCH;
    }
    // Test that the match is in a Comparable.compareTo or Comparator.compare method.
    ClassTree declaringClass = ASTHelpers.findEnclosingNode(state.getPath(), ClassTree.class);
    if (!COMPARABLE_CLASS_MATCHER.matches(declaringClass, state) && !COMPARATOR_CLASS_MATCHER.matches(declaringClass, state)) {
        return Description.NO_MATCH;
    }
    if (!COMPARABLE_METHOD_MATCHER.matches(tree, state) && !COMPARATOR_METHOD_MATCHER.matches(tree, state)) {
        return Description.NO_MATCH;
    }
    final Set<ComparisonResult> seenResults = EnumSet.noneOf(ComparisonResult.class);
    final TreeVisitor<Void, VisitorState> visitReturnExpression = new SimpleTreeVisitor<Void, VisitorState>() {

        @Override
        protected Void defaultAction(Tree node, VisitorState state) {
            seenResults.add(node.accept(CONSTANT_VISITOR, state));
            return null;
        }

        @Override
        public Void visitConditionalExpression(ConditionalExpressionTree node, VisitorState state) {
            node.getTrueExpression().accept(this, state);
            node.getFalseExpression().accept(this, state);
            return null;
        }
    };
    tree.getBody().accept(new TreeScanner<Void, VisitorState>() {

        @Override
        public Void visitReturn(ReturnTree node, VisitorState state) {
            return node.getExpression().accept(visitReturnExpression, state);
        }
    }, state);
    if (seenResults.isEmpty() || seenResults.contains(ComparisonResult.NONCONSTANT)) {
        return Description.NO_MATCH;
    }
    if (!seenResults.contains(ComparisonResult.ZERO)) {
        if (tree.getBody().getStatements().size() == 1 && tree.getBody().getStatements().get(0).getKind() == Kind.RETURN) {
            ReturnTree returnTree = (ReturnTree) tree.getBody().getStatements().get(0);
            if (returnTree.getExpression().getKind() == Kind.CONDITIONAL_EXPRESSION) {
                ConditionalExpressionTree condTree = (ConditionalExpressionTree) returnTree.getExpression();
                ExpressionTree conditionExpr = condTree.getCondition();
                while (conditionExpr instanceof ParenthesizedTree) {
                    conditionExpr = ((ParenthesizedTree) conditionExpr).getExpression();
                }
                if (!(conditionExpr instanceof BinaryTree)) {
                    return describeMatch(tree);
                }
                ComparisonResult trueConst = condTree.getTrueExpression().accept(CONSTANT_VISITOR, state);
                ComparisonResult falseConst = condTree.getFalseExpression().accept(CONSTANT_VISITOR, state);
                boolean trueFirst;
                if (trueConst == ComparisonResult.NEGATIVE_CONSTANT && falseConst == ComparisonResult.POSITIVE_CONSTANT) {
                    trueFirst = true;
                } else if (trueConst == ComparisonResult.POSITIVE_CONSTANT && falseConst == ComparisonResult.NEGATIVE_CONSTANT) {
                    trueFirst = false;
                } else {
                    return describeMatch(tree);
                }
                switch(conditionExpr.getKind()) {
                    case LESS_THAN:
                    case LESS_THAN_EQUAL:
                        break;
                    case GREATER_THAN:
                    case GREATER_THAN_EQUAL:
                        trueFirst = !trueFirst;
                        break;
                    default:
                        return describeMatch(tree);
                }
                BinaryTree binaryExpr = (BinaryTree) conditionExpr;
                Type ty = ASTHelpers.getType(binaryExpr.getLeftOperand());
                Types types = Types.instance(state.context);
                Symtab symtab = Symtab.instance(state.context);
                ExpressionTree first = trueFirst ? binaryExpr.getLeftOperand() : binaryExpr.getRightOperand();
                ExpressionTree second = trueFirst ? binaryExpr.getRightOperand() : binaryExpr.getLeftOperand();
                String compareType;
                if (types.isSameType(ty, symtab.intType)) {
                    compareType = "Integer";
                } else if (types.isSameType(ty, symtab.longType)) {
                    compareType = "Long";
                } else {
                    return describeMatch(tree);
                }
                return describeMatch(condTree, SuggestedFix.replace(condTree, String.format("%s.compare(%s, %s)", compareType, state.getSourceForNode(first), state.getSourceForNode(second))));
            }
        }
        return describeMatch(tree);
    }
    if (COMPARATOR_METHOD_MATCHER.matches(tree, state) && (seenResults.contains(ComparisonResult.NEGATIVE_CONSTANT) != seenResults.contains(ComparisonResult.POSITIVE_CONSTANT))) {
        // See e.g. com.google.common.collect.Cut.BelowAll.
        return describeMatch(tree);
    } else {
        return Description.NO_MATCH;
    }
}