Add validation for single statement lexical declarations (#3326)

This patch fixes #3275 and fixes #3276.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

tests/jerry/es2015/let12.js

@@ -0,0 +1,41 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+function checkSyntax (str) {
+  try {
+    eval (str);
+    assert (false);
+  } catch (e) {
+    assert (e instanceof SyntaxError);
+  }
+}
+
+checkSyntax ("if (5) let a;");
+checkSyntax ("if (5) const a;");
+checkSyntax ("if (0) {} else let a;");
+checkSyntax ("if (0) {} else const a;");
+checkSyntax ("while (5) let a;");
+checkSyntax ("while (5) const a;");
+checkSyntax ("do let a; while (5)");
+checkSyntax ("do const a; while (5)");
+checkSyntax ("for (a in b) let c;");
+checkSyntax ("for (a in b) const c;");
+checkSyntax ("for (a of b) let c;");
+checkSyntax ("for (a of b) const c;");
+checkSyntax ("for (;;) let c;");
+checkSyntax ("for (;;) const c;");
+checkSyntax ("with ({}) let c;");
+checkSyntax ("with ({}) const c;");
+checkSyntax ("a: let c;");
+checkSyntax ("a: const c;");

tests/jerry/fail/regression-test-issue-3276.js

@@ -12,4 +12,4 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-do class $ { } while (0);
+with ({ }) class ${ $( ) { $ } }

tests/jerry/fail/regresssion-test-issue-3275.js

@@ -0,0 +1,15 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+for ( i in this ) class ${ } eval ( )