[GR-25621] Fix cast exception on syntax error

PullRequest: graalpython/1202

Author: msimacek

graalpython/com.oracle.graal.python.test/src/tests/test_parser.py

@@ -158,3 +158,12 @@ def assert_raise(s, msg):
         assert_raise("''", "cannot assign to literal")
         assert_raise("f''", "cannot assign to f-string expression")
         assert_raise("(None,)", "cannot assign to None")
+
+
+def test_invalid_ann_assignment():
+    try:
+        exec("lambda: x:x")
+    except SyntaxError as e:
+        assert e.msg == 'illegal target for annotation'
+        return
+    assert False, "SyntaxError not raised"

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/ErrorMessages.java

@@ -546,4 +546,6 @@ public abstract class ErrorMessages {
     public static final String CANNOT_CONVERT_NEGATIVE_VALUE_TO_UNSIGNED_INT = "can't convert negative value to unsigned int";
     public static final String SEND_NON_NONE_TO_UNSTARTED_GENERATOR = "can't send non-None value to a just-started generator";
     public static final String UNSUPPORTED_FORMAT_STRING_PASSED_TO_P_FORMAT = "unsupported format string passed to %p.__format__";
+    public static final String ONLY_SINGLE_TARGET_CAN_BE_ANNOTATED = "only single target (not %s) can be annotated";
+    public static final String ILLEGAL_TARGET_FOR_ANNOTATION = "illegal target for annotation";
 }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/parser/PythonSSTNodeFactory.java

@@ -210,9 +210,6 @@ public SSTNode createAssignment(SSTNode[] lhs, SSTNode rhs, int start, int stop)
     }
 
     public SSTNode createAnnAssignment(SSTNode lhs, SSTNode type, SSTNode rhs, int start, int end) {
-        if (lhs instanceof CollectionSSTNode) {
-            throw errors.raiseInvalidSyntax(source, createSourceSection(lhs.getStartOffset(), lhs.getEndOffset()), "only single target (not tuple) can be annotated");
-        }
         declareVar(lhs);
         if (!scopeEnvironment.getCurrentScope().hasAnnotations()) {
             scopeEnvironment.getCurrentScope().setHasAnnotations(true);

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/parser/sst/FactorySSTVisitor.java

@@ -275,7 +275,7 @@ public PNode visit(AndSSTNode node) {
 
     @Override
     public PNode visit(AnnAssignmentSSTNode node) {
-        PNode assignmentNode = visit((AssignmentSSTNode) node);
+        PNode assignmentNode = createAssignment(node, true);
         if (!scopeEnvironment.isInFunctionScope() && node.type != null && node.lhs.length == 1 && node.lhs[0] instanceof VarLookupSSTNode) {
             // annotations in a function we ignore at all. Even there are not evalueated, whether
             // the type is wrong
@@ -303,12 +303,25 @@ public PNode visit(AssertSSTNode node) {
 
     @Override
     public PNode visit(AssignmentSSTNode node) {
+        return createAssignment(node, false);
+    }
+
+    public StatementNode createAssignment(AssignmentSSTNode node, boolean checkAnnotationPermitted) {
         ExpressionNode[] lhs = new ExpressionNode[node.lhs.length];
         int numYields = getCurrentNumberOfYields();
         for (int i = 0; i < node.lhs.length; i++) {
             SSTNode sstLhs = node.lhs[i];
             checkCannotAssignTo(sstLhs);
             lhs[i] = (ExpressionNode) sstLhs.accept(this);
+            if (checkAnnotationPermitted) {
+                if (lhs[i] instanceof TupleLiteralNode) {
+                    throw errors.raiseInvalidSyntax(source, createSourceSection(sstLhs.getStartOffset(), sstLhs.getEndOffset()), ErrorMessages.ONLY_SINGLE_TARGET_CAN_BE_ANNOTATED, "tuple");
+                } else if (lhs[i] instanceof ListLiteralNode) {
+                    throw errors.raiseInvalidSyntax(source, createSourceSection(sstLhs.getStartOffset(), sstLhs.getEndOffset()), ErrorMessages.ONLY_SINGLE_TARGET_CAN_BE_ANNOTATED, "list");
+                } else if (!(lhs[i] instanceof ReadNode)) {
+                    throw errors.raiseInvalidSyntax(source, createSourceSection(sstLhs.getStartOffset(), sstLhs.getEndOffset()), ErrorMessages.ILLEGAL_TARGET_FOR_ANNOTATION);
+                }
+            }
         }
         ExpressionNode rhs = (ExpressionNode) node.rhs.accept(this);