track_caller run-pass test, lint cleanup, PR review.

Author: anp

src/librustc/error_codes.rs

@@ -1728,13 +1728,13 @@ attribute.
 "##,
 
 E0900: r##"
-TODO: change error number
-TODO: track_caller: invalid syntax
+FIXME(anp): change error number
+FIXME(anp): track_caller: invalid syntax
 "##,
 
 E0901: r##"
-TODO: change error number
-TODO: track_caller: no naked functions
+FIXME(anp): change error number
+FIXME(anp): track_caller: no naked functions
 "##,
 
 E0522: r##"

src/librustc/hir/check_attr.rs

@@ -11,7 +11,7 @@ use crate::ty::TyCtxt;
 use crate::ty::query::Providers;
 
 use std::fmt::{self, Display};
-use syntax::symbol::sym;
+use syntax::{attr, symbol::sym};
 use syntax_pos::Span;
 
 #[derive(Copy, Clone, PartialEq)]
@@ -94,7 +94,6 @@ impl CheckAttrVisitor<'tcx> {
     /// Checks any attribute.
     fn check_attributes(&self, item: &hir::Item, target: Target) {
         let mut is_valid = true;
-        let mut track_caller_span = None;
         for attr in &item.attrs {
             is_valid &= if attr.check_name(sym::inline) {
                 self.check_inline(attr, &item.span, target)
@@ -105,7 +104,6 @@ impl CheckAttrVisitor<'tcx> {
             } else if attr.check_name(sym::target_feature) {
                 self.check_target_feature(attr, item, target)
             } else if attr.check_name(sym::track_caller) {
-                track_caller_span = Some(attr.span);
                 self.check_track_caller(attr, &item, target)
             } else {
                 true
@@ -122,19 +120,6 @@ impl CheckAttrVisitor<'tcx> {
 
         self.check_repr(item, target);
         self.check_used(item, target);
-
-        // Checks if `#[track_caller]` and `#[naked]` are both used.
-        if let Some(span) = track_caller_span {
-            if item.attrs.iter().any(|attr| attr.check_name(sym::naked)) {
-                struct_span_err!(
-                    self.tcx.sess,
-                    span,
-                    E0901,
-                    "cannot use `#[track_caller]` with `#[naked]`",
-                )
-                .emit();
-            }
-        }
     }
 
     /// Checks if an `#[inline]` is applied to a function or a closure. Returns `true` if valid.
@@ -152,7 +137,7 @@ impl CheckAttrVisitor<'tcx> {
         }
     }
 
-    /// Checks if a `#[target_feature]` can be applied.
+    /// Checks if a `#[track_caller]` is applied to a non-naked function. Returns `true` if valid.
     fn check_track_caller(&self, attr: &hir::Attribute, item: &hir::Item, target: Target) -> bool {
         if target != Target::Fn {
             struct_span_err!(
@@ -164,6 +149,15 @@ impl CheckAttrVisitor<'tcx> {
             .span_label(item.span, "not a function")
             .emit();
             false
+        } else if attr::contains_name(&item.attrs, sym::naked) {
+            struct_span_err!(
+                self.tcx.sess,
+                attr.span,
+                E0901,
+                "cannot use `#[track_caller]` with `#[naked]`",
+            )
+            .emit();
+            false
         } else {
             true
         }

src/librustc_typeck/error_codes.rs

@@ -4909,13 +4909,13 @@ and the pin is required to keep it in the same place in memory.
 "##,
 
 E0902: r##"
-TODO: change error number
-TODO: track_caller: require Rust ABI to use track_caller
+FIXME(anp): change error number
+FIXME(anp): track_caller: require Rust ABI to use track_caller
 "##,
 
 E0903: r##"
-TODO: change error number
-TODO: track_caller: can't apply in traits
+FIXME(anp): change error number
+FIXME(anp): track_caller: can't apply in traits
 "##,
 
 ;

src/libsyntax/feature_gate/active.rs

@@ -520,7 +520,7 @@ declare_features! (
     (active, or_patterns, "1.38.0", Some(54883), None),
 
     /// Enable accurate caller location reporting during panic (RFC 2091).
-    (active, track_caller, "1.37.0", Some(47809), None),
+    (active, track_caller, "1.39.0", Some(47809), None),
 
     // -------------------------------------------------------------------------
     // feature-group-end: actual feature gates

src/libsyntax/feature_gate/builtin_attrs.rs

@@ -307,6 +307,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     ),
 
     gated!(ffi_returns_twice, Whitelisted, template!(Word), experimental!(ffi_returns_twice)),
+    gated!(track_caller, Whitelisted, template!(Word), experimental!(track_caller)),
 
     // ==========================================================================
     // Internal attributes: Stability, deprecation, and unsafe:
@@ -482,10 +483,6 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
             cfg_fn!(no_debug)
         )
     ),
-    gated!(
-        track_caller, Whitelisted, template!(Word),
-        "the `#[track_caller]` attribute is an experimental feature",
-    ),
     gated!(
         // Used in resolve:
         prelude_import, Whitelisted, template!(Word),

src/test/ui/feature-gates/feature-gate-track_caller.rs

@@ -1,4 +1,3 @@
-
 #[track_caller]
 fn f() {}
 //~^^ ERROR the `#[track_caller]` attribute is an experimental feature

src/test/ui/feature-gates/feature-gate-track_caller.stderr

@@ -1,5 +1,5 @@
 error[E0658]: the `#[track_caller]` attribute is an experimental feature
-  --> $DIR/feature-gate-track_caller.rs:2:1
+  --> $DIR/feature-gate-track_caller.rs:1:1
    |
 LL | #[track_caller]
    | ^^^^^^^^^^^^^^^

src/test/ui/rfc-2091-track-caller/pass.rs

@@ -0,0 +1,9 @@
+// run-pass
+#![feature(track_caller)]
+
+#[track_caller]
+fn f() {}
+
+fn main() {
+    f();
+}