Ported effect checker from oldvisit to <V:Visitor> trait API.

Author: pnkfelix

src/librustc/middle/effect.rs

@@ -20,8 +20,10 @@ use syntax::ast::{deref, expr_call, expr_inline_asm, expr_method_call};
 use syntax::ast::{expr_unary, unsafe_fn, expr_path};
 use syntax::ast;
 use syntax::codemap::span;
-use syntax::oldvisit::{fk_item_fn, fk_method};
-use syntax::oldvisit;
+use syntax::visit::{fk_item_fn, fk_method};
+use syntax::visit;
+use syntax::visit::{Visitor,fn_kind};
+use syntax::ast::{fn_decl,Block,NodeId,expr};
 
 #[deriving(Eq)]
 enum UnsafeContext {
@@ -45,120 +47,133 @@ fn type_is_unsafe_function(ty: ty::t) -> bool {
     }
 }
 
-pub fn check_crate(tcx: ty::ctxt,
-                   method_map: method_map,
-                   crate: &ast::Crate) {
-    let context = @mut Context {
-        method_map: method_map,
-        unsafe_context: SafeContext,
-    };
+struct EffectCheckVisitor {
+    tcx: ty::ctxt,
+    context: @mut Context,
+}
 
-    let require_unsafe: @fn(span: span,
-                            description: &str) = |span, description| {
-        match context.unsafe_context {
+impl EffectCheckVisitor {
+    fn require_unsafe(&mut self, span: span, description: &str) {
+        match self.context.unsafe_context {
             SafeContext => {
                 // Report an error.
-                tcx.sess.span_err(span,
+                self.tcx.sess.span_err(span,
                                   fmt!("%s requires unsafe function or block",
                                        description))
             }
             UnsafeBlock(block_id) => {
                 // OK, but record this.
                 debug!("effect: recording unsafe block as used: %?", block_id);
-                let _ = tcx.used_unsafe.insert(block_id);
+                let _ = self.tcx.used_unsafe.insert(block_id);
             }
             UnsafeFn => {}
         }
-    };
+    }
+}
+
+impl Visitor<()> for EffectCheckVisitor {
+    fn visit_fn(&mut self, fn_kind:&fn_kind, fn_decl:&fn_decl,
+                block:&Block, span:span, node_id:NodeId, _:()) {
 
-    let visitor = oldvisit::mk_vt(@oldvisit::Visitor {
-        visit_fn: |fn_kind, fn_decl, block, span, node_id, (_, visitor)| {
             let (is_item_fn, is_unsafe_fn) = match *fn_kind {
                 fk_item_fn(_, _, purity, _) => (true, purity == unsafe_fn),
                 fk_method(_, _, method) => (true, method.purity == unsafe_fn),
                 _ => (false, false),
             };
 
-            let old_unsafe_context = context.unsafe_context;
+            let old_unsafe_context = self.context.unsafe_context;
             if is_unsafe_fn {
-                context.unsafe_context = UnsafeFn
+                self.context.unsafe_context = UnsafeFn
             } else if is_item_fn {
-                context.unsafe_context = SafeContext
+                self.context.unsafe_context = SafeContext
             }
 
-            oldvisit::visit_fn(fn_kind,
+            visit::walk_fn(self,
+                           fn_kind,
                             fn_decl,
                             block,
                             span,
                             node_id,
-                            ((),
-                             visitor));
+                            ());
+
+            self.context.unsafe_context = old_unsafe_context
+    }
 
-            context.unsafe_context = old_unsafe_context
-        },
+    fn visit_block(&mut self, block:&Block, _:()) {
 
-        visit_block: |block, (_, visitor)| {
-            let old_unsafe_context = context.unsafe_context;
+            let old_unsafe_context = self.context.unsafe_context;
             if block.rules == ast::UnsafeBlock &&
-                    context.unsafe_context == SafeContext {
-                context.unsafe_context = UnsafeBlock(block.id)
+                    self.context.unsafe_context == SafeContext {
+                self.context.unsafe_context = UnsafeBlock(block.id)
             }
 
-            oldvisit::visit_block(block, ((), visitor));
+            visit::walk_block(self, block, ());
 
-            context.unsafe_context = old_unsafe_context
-        },
+            self.context.unsafe_context = old_unsafe_context
+    }
+
+    fn visit_expr(&mut self, expr:@expr, _:()) {
 
-        visit_expr: |expr, (_, visitor)| {
             match expr.node {
                 expr_method_call(callee_id, _, _, _, _, _) => {
-                    let base_type = ty::node_id_to_type(tcx, callee_id);
+                    let base_type = ty::node_id_to_type(self.tcx, callee_id);
                     debug!("effect: method call case, base type is %s",
-                           ppaux::ty_to_str(tcx, base_type));
+                           ppaux::ty_to_str(self.tcx, base_type));
                     if type_is_unsafe_function(base_type) {
-                        require_unsafe(expr.span,
+                        self.require_unsafe(expr.span,
                                        "invocation of unsafe method")
                     }
                 }
                 expr_call(base, _, _) => {
-                    let base_type = ty::node_id_to_type(tcx, base.id);
+                    let base_type = ty::node_id_to_type(self.tcx, base.id);
                     debug!("effect: call case, base type is %s",
-                           ppaux::ty_to_str(tcx, base_type));
+                           ppaux::ty_to_str(self.tcx, base_type));
                     if type_is_unsafe_function(base_type) {
-                        require_unsafe(expr.span, "call to unsafe function")
+                        self.require_unsafe(expr.span, "call to unsafe function")
                     }
                 }
                 expr_unary(_, deref, base) => {
-                    let base_type = ty::node_id_to_type(tcx, base.id);
+                    let base_type = ty::node_id_to_type(self.tcx, base.id);
                     debug!("effect: unary case, base type is %s",
-                           ppaux::ty_to_str(tcx, base_type));
+                           ppaux::ty_to_str(self.tcx, base_type));
                     match ty::get(base_type).sty {
                         ty_ptr(_) => {
-                            require_unsafe(expr.span,
+                            self.require_unsafe(expr.span,
                                            "dereference of unsafe pointer")
                         }
                         _ => {}
                     }
                 }
                 expr_inline_asm(*) => {
-                    require_unsafe(expr.span, "use of inline assembly")
+                    self.require_unsafe(expr.span, "use of inline assembly")
                 }
                 expr_path(*) => {
-                    match ty::resolve_expr(tcx, expr) {
+                    match ty::resolve_expr(self.tcx, expr) {
                         ast::def_static(_, true) => {
-                            require_unsafe(expr.span, "use of mutable static")
+                            self.require_unsafe(expr.span, "use of mutable static")
                         }
                         _ => {}
                     }
                 }
                 _ => {}
             }
 
-            oldvisit::visit_expr(expr, ((), visitor))
-        },
+            visit::walk_expr(self, expr, ());
+    }
+}
 
-        .. *oldvisit::default_visitor()
-    });
+pub fn check_crate(tcx: ty::ctxt,
+                   method_map: method_map,
+                   crate: &ast::Crate) {
+    let context = @mut Context {
+        method_map: method_map,
+        unsafe_context: SafeContext,
+    };
+
+    let mut visitor = EffectCheckVisitor {
+        tcx: tcx,
+        context: context,
+    };
 
-    oldvisit::visit_crate(crate, ((), visitor))
+    visit::walk_crate(&mut visitor, crate, ());
 }