Fix bug in typechecker where prev context was not restored

Author: polybuildr

src/typechecker.rs

@@ -680,6 +680,7 @@ impl TypeChecker {
                         self.issues = outer_issues;
                         let ret_type;
                         if let StmtEffect::None = fn_body_effect {
+                            self.context = old_context;
                             None
                         } else {
                             match self.context.func_ret_type {

tests/typecheck-fail/break-return-outside.bl

@@ -0,0 +1,5 @@
+fn test() {
+    break;
+}
+test();
+return 5;

tests/typecheck-fail/break-return-outside.err

@@ -0,0 +1 @@
+[(InsideFunctionCall((RuntimeError(BreakOutsideLoop), (16, 22))), (25, 31)), (RuntimeError(ReturnOutsideFunction), (33, 42))]