[GR-18927] Python parser doesn't throw syntax error if yield is used outside a function.

Author: ppisl

graalpython/com.oracle.graal.python.test/src/com/oracle/graal/python/test/parser/YieldStatementTests.java

@@ -338,4 +338,29 @@ public void try03() throws Exception {
                                         "  except ValueError:\n" +
                                         "    pass");
     }
+
+    @Test
+    public void syntaxEror01() throws Exception {
+        checkSyntaxErrorMessageContains("yield", "'yield' outside function");
+    }
+
+    @Test
+    public void syntaxEror02() throws Exception {
+        checkSyntaxErrorMessageContains("yield from", "invalid syntax");
+    }
+
+    @Test
+    public void syntaxEror03() throws Exception {
+        checkSyntaxErrorMessageContains("class foo:yield 1", "'yield' outside function");
+    }
+
+    @Test
+    public void syntaxEror04() throws Exception {
+        checkSyntaxErrorMessageContains("class foo:yield from ()", "'yield' outside function");
+    }
+
+    @Test
+    public void syntaxEror05() throws Exception {
+        checkSyntaxErrorMessageContains("def g(a:(yield)): pass", "'yield' outside function");
+    }
 }

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

@@ -211,6 +211,9 @@ private void createLocalVariable(SSTNode var) {
     }
 
     public YieldExpressionSSTNode createYieldExpressionSSTNode(SSTNode value, boolean isFrom, int startOffset, int endOffset) {
+        if (!scopeEnvironment.isInFunctionScope()) {
+            throw errors.raiseInvalidSyntax(source, createSourceSection(startOffset, endOffset), "'yield' outside function");
+        }
         scopeEnvironment.setToGeneratorScope();
         return new YieldExpressionSSTNode(value, isFrom, startOffset, endOffset);
     }