sema: check access to symbols in PathExpr

bsc/sema.py

@@ -325,6 +325,11 @@ def check_path_expr(self, expr: PathExpr):
 
         if path_sym := expr.left_sym.scope.find(expr.name):
             expr.sym = path_sym
+            if not self.cur_sym.has_access_to(path_sym):
+                report.error(
+                    f"cannot access private {path_sym.kind_of()} `{path_sym.name}`",
+                    expr.pos
+                )
         else:
             report.error(
                 f"{expr.left_sym.kind_of()} `{expr.left_sym}` does not contain a symbol named `{expr.name}`",
@@ -337,9 +342,9 @@ def check_symbol(self, name, pos):
         ret_sym = None
         if local_sym := self.cur_scope.lookup(name):
             ret_sym = local_sym
-        elif symbol_sym := self.cur_sym.scope.lookup(name):
+        elif symbol_sym := self.cur_sym.scope.find(name):
             ret_sym = symbol_sym
-        elif module_sym := self.cur_mod.scope.lookup(name):
+        elif module_sym := self.cur_mod.scope.find(name):
             ret_sym = module_sym
         else:
             report.error(f"cannot find symbol `{name}` in this scope", pos)

bsc/sym.py

@@ -44,6 +44,36 @@ def __init__(self, access_modifier, name, pos = None):
         self.name = name
         self.pos = pos
 
+    def get_pkg(self):
+        s = self
+        while True:
+            if isinstance(s, Module) and s.is_pkg:
+                return s
+            if s.parent == None:
+                break
+            s = s.parent
+        return None
+
+    def get_mod(self):
+        s = self
+        while True:
+            if isinstance(s, Module):
+                return s
+            if s.parent == None:
+                break
+            s = s.parent
+        return None
+
+    def has_access_to(self, other):
+        match other.access_modifier:
+            case AccessModifier.public:
+                return True # other is public
+            case AccessModifier.internal:
+                return self.get_pkg() == other.get_pkg()
+            case AccessModifier.private:
+                return self.get_mod() == other.get_mod()
+        return False
+
     def kind_of(self):
         if isinstance(self, Module):
             return "package" if self.is_pkg else "module"

tests/invalid_code/access_modifer.bs

@@ -0,0 +1,9 @@
+mod my_mod {
+    const x = 1;
+    pub const v = 4;
+}
+
+fn main() {
+    const my_x = my_mod::x; // error
+    const my_v = my_mod::v; // ok
+}

tests/invalid_code/access_modifer.out

@@ -0,0 +1 @@
+tests/invalid_code/access_modifer.bs:7:26: error: cannot access private constant `x`