Rollup merge of #64471 - Mark-Simulacrum:warn-depr-attr, r=Centril

Warn on no_start, crate_id attribute use

These attributes are now deprecated; they don't have any use anymore.

`no_start` stopped being applicable in 3ee916e as part of #18967. Ideally we would've removed it pre-1.0, but since that didn't happen let's at least mark it deprecated.

`crate_id` was renamed to `crate_name` in 50ee1ec as part of #15319. Ideally we would've followed that up with a removal of crate_id itself as well, but that didn't happen; this PR finally marks it as deprecated at least.

Fixes #43142 and resolves #43144.

Author: Centril

src/librustc_lint/builtin.rs

@@ -669,6 +669,22 @@ impl DeprecatedAttr {
     }
 }
 
+fn lint_deprecated_attr(
+    cx: &EarlyContext<'_>,
+    attr: &ast::Attribute,
+    msg: &str,
+    suggestion: Option<&str>,
+) {
+    cx.struct_span_lint(DEPRECATED, attr.span, &msg)
+        .span_suggestion_short(
+            attr.span,
+            suggestion.unwrap_or("remove this attribute"),
+            String::new(),
+            Applicability::MachineApplicable
+        )
+        .emit();
+}
+
 impl EarlyLintPass for DeprecatedAttr {
     fn check_attribute(&mut self, cx: &EarlyContext<'_>, attr: &ast::Attribute) {
         for &&(n, _, _, ref g) in &self.depr_attrs {
@@ -679,18 +695,15 @@ impl EarlyLintPass for DeprecatedAttr {
                                              _) = g {
                     let msg = format!("use of deprecated attribute `{}`: {}. See {}",
                                       name, reason, link);
-                    let mut err = cx.struct_span_lint(DEPRECATED, attr.span, &msg);
-                    err.span_suggestion_short(
-                        attr.span,
-                        suggestion.unwrap_or("remove this attribute"),
-                        String::new(),
-                        Applicability::MachineApplicable
-                    );
-                    err.emit();
+                    lint_deprecated_attr(cx, attr, &msg, suggestion);
                 }
                 return;
             }
         }
+        if attr.check_name(sym::no_start) || attr.check_name(sym::crate_id) {
+            let msg = format!("use of deprecated attribute `{}`: no longer used.", attr.path);
+            lint_deprecated_attr(cx, attr, &msg, None);
+        }
     }
 }
 

src/test/ui/attributes/item-attributes.rs

@@ -11,8 +11,6 @@
 #![rustc_dummy]
 #![rustc_dummy(attr5)]
 
-#![crate_id="foobar#0.1"]
-
 // These are attributes of the following mod
 #[rustc_dummy = "val"]
 #[rustc_dummy = "val"]

src/test/ui/feature-gate/issue-43106-gating-of-builtin-attrs.rs

@@ -84,12 +84,12 @@
 #![crate_name = "0900"]
 #![crate_type = "bin"] // cannot pass "0800" here
 
-// For #![crate_id], see issue #43142. (I cannot bear to enshrine current behavior in a test)
+#![crate_id = "10"] //~ WARN use of deprecated attribute
 
 // FIXME(#44232) we should warn that this isn't used.
 #![feature(rust1)]
 
-// For #![no_start], see issue #43144. (I cannot bear to enshrine current behavior in a test)
+#![no_start] //~ WARN use of deprecated attribute
 
 // (cannot easily gating state of crate-level #[no_main]; but non crate-level is below at "0400")
 #![no_builtins]

src/test/ui/feature-gate/issue-43106-gating-of-builtin-attrs.stderr

@@ -186,6 +186,20 @@ LL |     mod inner { #![macro_escape] }
    |
    = help: consider an outer attribute, `#[macro_use]` mod ...
 
+warning: use of deprecated attribute `crate_id`: no longer used.
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:87:1
+   |
+LL | #![crate_id = "10"]
+   | ^^^^^^^^^^^^^^^^^^^ help: remove this attribute
+   |
+   = note: `#[warn(deprecated)]` on by default
+
+warning: use of deprecated attribute `no_start`: no longer used.
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:92:1
+   |
+LL | #![no_start]
+   | ^^^^^^^^^^^^ help: remove this attribute
+
 warning: the feature `rust1` has been stable since 1.0.0 and no longer requires an attribute to enable
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:90:12
    |

src/test/ui/issues/issue-1251.rs

@@ -6,8 +6,6 @@
 
 #![feature(rustc_private)]
 
-#![crate_id="rust_get_test_int"]
-
 mod rustrt {
     extern crate libc;
 

src/test/ui/issues/issue-6919.rs

@@ -4,7 +4,6 @@
 
 // pretty-expanded FIXME #23616
 
-#![crate_id="issue-6919"]
 extern crate issue6919_3;
 
 pub fn main() {