Initial AST validation for using-for

crates/sema/src/ast_passes.rs

@@ -26,12 +26,19 @@ struct AstValidator<'sess> {
     span: Span,
     dcx: &'sess DiagCtxt,
     in_loop_depth: u64,
+    contract_kind: Option<ast::ContractKind>,
     in_unchecked_block: bool,
 }
 
 impl<'sess> AstValidator<'sess> {
     fn new(sess: &'sess Session) -> Self {
-        Self { span: Span::DUMMY, dcx: &sess.dcx, in_loop_depth: 0, in_unchecked_block: false }
+        Self {
+            span: Span::DUMMY,
+            dcx: &sess.dcx,
+            in_loop_depth: 0,
+            in_unchecked_block: false,
+            contract_kind: None,
+        }
     }
 
     /// Returns the diagnostics context.
@@ -123,6 +130,48 @@ impl<'ast> Visit<'ast> for AstValidator<'_> {
         self.walk_stmt(stmt)
     }
 
+    fn visit_item_contract(
+        &mut self,
+        contract: &'ast ast::ItemContract<'ast>,
+    ) -> ControlFlow<Self::BreakValue> {
+        self.contract_kind = Some(contract.kind);
+        let r = self.walk_item_contract(contract);
+        self.contract_kind = None;
+        r
+    }
+
+    fn visit_using_directive(
+        &mut self,
+        using: &'ast ast::UsingDirective<'ast>,
+    ) -> ControlFlow<Self::BreakValue> {
+        let ast::UsingDirective { list: _, ty, global } = using;
+        let with_typ = ty.is_some();
+        if self.contract_kind.is_none() && !with_typ {
+            self.dcx()
+                .err("the type has to be specified explicitly at file level (cannot use `*`)")
+                .span(self.span)
+                .emit();
+        }
+        if *global && !with_typ {
+            self.dcx()
+                .err("can only globally attach functions to specific types")
+                .span(self.span)
+                .emit();
+        }
+        if *global && self.contract_kind.is_some() {
+            self.dcx().err("`global` can only be used at file level").span(self.span).emit();
+        }
+        if let Some(contract_kind) = self.contract_kind {
+            if contract_kind == ast::ContractKind::Interface {
+                self.dcx()
+                    .err("the `using for` directive is not allowed inside interfaces")
+                    .span(self.span)
+                    .emit();
+            }
+        }
+        self.walk_using_directive(using)
+    }
+
     // Intentionally override unused default implementations to reduce bloat.
     fn visit_expr(&mut self, _expr: &'ast ast::Expr<'ast>) -> ControlFlow<Self::BreakValue> {
         ControlFlow::Continue(())

tests/ui/parser/using.sol

@@ -0,0 +1,13 @@
+using {f} for * global; //~ ERROR: can only globally attach functions to specific types
+//~^ ERROR: the type has to be specified explicitly at file level (cannot use `*`)
+function f(uint) pure {}
+
+contract C {
+    using {f} for uint global; //~ ERROR: `global` can only be used at file level
+}
+function f(uint) pure {}
+
+interface I2 {
+    using L for int; //~ ERROR: the `using for` directive is not allowed inside interfaces
+    function g() external;
+}

tests/ui/parser/using.stderr

@@ -0,0 +1,30 @@
+error: the type has to be specified explicitly at file level (cannot use `*`)
+  --> ROOT/tests/ui/parser/using.sol:LL:CC
+   |
+LL | using {f} for * global;
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+
+error: can only globally attach functions to specific types
+  --> ROOT/tests/ui/parser/using.sol:LL:CC
+   |
+LL | using {f} for * global;
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+
+error: `global` can only be used at file level
+  --> ROOT/tests/ui/parser/using.sol:LL:CC
+   |
+LL |     using {f} for uint global;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+
+error: the `using for` directive is not allowed inside interfaces
+  --> ROOT/tests/ui/parser/using.sol:LL:CC
+   |
+LL |     using L for int;
+   |     ^^^^^^^^^^^^^^^^
+   |
+
+error: aborting due to 4 previous errors
+