From 81b69d153869062af6992dc2c99c5536c7ff99f0 Mon Sep 17 00:00:00 2001
From: Aaron Turon <aturon@mozilla.com>
Date: Wed, 16 Jul 2014 13:50:33 -0700
Subject: [PATCH] stability lint: ignore code from macro expansion

This small patch causes the stability lint to bail out when traversing
any AST produced via a macro expansion. Ultimately, we would like to
lint the contents of the macro at the place where the macro is defined,
but regardless we should not be linting it at the use site.

Closes #15703
---
 src/librustc/lint/builtin.rs            |  3 +++
 src/test/auxiliary/lint_stability.rs    |  8 ++++++++
 src/test/compile-fail/lint-stability.rs | 11 +++++++++--
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/librustc/lint/builtin.rs b/src/librustc/lint/builtin.rs
index 62236d753ad26..fbe4b211f9752 100644
--- a/src/librustc/lint/builtin.rs
+++ b/src/librustc/lint/builtin.rs
@@ -1433,6 +1433,9 @@ impl LintPass for Stability {
     }
 
     fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
+        // if the expression was produced by a macro expansion,
+        if e.span.expn_info.is_some() { return }
+
         let id = match e.node {
             ast::ExprPath(..) | ast::ExprStruct(..) => {
                 match cx.tcx.def_map.borrow().find(&e.id) {
diff --git a/src/test/auxiliary/lint_stability.rs b/src/test/auxiliary/lint_stability.rs
index b63aa18b75d34..b0090c63969ab 100644
--- a/src/test/auxiliary/lint_stability.rs
+++ b/src/test/auxiliary/lint_stability.rs
@@ -10,6 +10,9 @@
 #![crate_id="lint_stability#0.1"]
 #![crate_type = "lib"]
 
+#![feature(macro_rules)]
+#![macro_escape]
+
 #[deprecated]
 pub fn deprecated() {}
 #[deprecated="text"]
@@ -173,3 +176,8 @@ pub struct StableTupleStruct(pub int);
 pub struct FrozenTupleStruct(pub int);
 #[locked]
 pub struct LockedTupleStruct(pub int);
+
+#[macro_export]
+macro_rules! macro_test(
+    () => (deprecated());
+)
diff --git a/src/test/compile-fail/lint-stability.rs b/src/test/compile-fail/lint-stability.rs
index 5d06ad79c9bdf..3a9380befbcb4 100644
--- a/src/test/compile-fail/lint-stability.rs
+++ b/src/test/compile-fail/lint-stability.rs
@@ -11,13 +11,14 @@
 // aux-build:lint_stability.rs
 // aux-build:inherited_stability.rs
 
-#![feature(globs)]
+#![feature(globs, phase)]
 #![deny(unstable)]
 #![deny(deprecated)]
 #![deny(experimental)]
 #![allow(dead_code)]
 
 mod cross_crate {
+    #[phase(plugin, link)]
     extern crate lint_stability;
     use self::lint_stability::*;
 
@@ -76,7 +77,6 @@ mod cross_crate {
         foo.method_locked_text();
         foo.trait_locked_text();
 
-
         let _ = DeprecatedStruct { i: 0 }; //~ ERROR use of deprecated item
         let _ = ExperimentalStruct { i: 0 }; //~ ERROR use of experimental item
         let _ = UnstableStruct { i: 0 }; //~ ERROR use of unstable item
@@ -108,6 +108,13 @@ mod cross_crate {
         let _ = StableTupleStruct (1);
         let _ = FrozenTupleStruct (1);
         let _ = LockedTupleStruct (1);
+
+        // At the moment, the following just checks that the stability
+        // level of expanded code does not trigger the
+        // lint. Eventually, we will want to lint the contents of the
+        // macro in the module *defining* it. Also, stability levels
+        // on macros themselves are not yet linted.
+        macro_test!();
     }
 
     fn test_method_param<F: Trait>(foo: F) {