invert dependency on rustc_error_messages

Author: mejrs

Cargo.lock

@@ -3976,7 +3976,6 @@ dependencies = [
  "rustc_macros",
  "rustc_serialize",
  "rustc_span",
- "rustc_structures",
  "unic-langid",
 ]
 
@@ -4788,6 +4787,7 @@ version = "0.0.0"
 dependencies = [
  "bitflags",
  "rustc_data_structures",
+ "rustc_error_messages",
  "rustc_macros",
  "rustc_serialize",
  "schemars",

compiler/rustc_error_messages/Cargo.toml

@@ -14,6 +14,5 @@ rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_span = { path = "../rustc_span" }
-rustc_structures = { path = "../rustc_structures" }
 unic-langid = { version = "0.9.0", features = ["macros"] }
 # tidy-alphabetical-end

compiler/rustc_error_messages/src/diagnostic_impls.rs

@@ -6,7 +6,6 @@ use std::path::{Path, PathBuf};
 use std::process::ExitStatus;
 
 use rustc_span::edition::Edition;
-use rustc_structures::Limit;
 
 use crate::{DiagArgValue, IntoDiagArg};
 
@@ -157,9 +156,3 @@ impl IntoDiagArg for Backtrace {
         DiagArgValue::Str(Cow::from(self.to_string()))
     }
 }
-
-impl IntoDiagArg for Limit {
-    fn into_diag_arg(self, _: &mut Option<std::path::PathBuf>) -> DiagArgValue {
-        self.0.into_diag_arg(&mut None)
-    }
-}

compiler/rustc_structures/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2024"
 # tidy-alphabetical-start
 bitflags = "2.4.1"
 rustc_data_structures = { path = "../rustc_data_structures", optional = true  }
+rustc_error_messages = { path = "../rustc_error_messages", optional = true  }
 rustc_macros = { path = "../rustc_macros", optional = true  }
 rustc_serialize = { path = "../rustc_serialize", optional = true  }
 schemars = "1.0.4"
@@ -18,6 +19,7 @@ serde = "1.0.219"
 default = ["nightly"]
 nightly = [
     "dep:rustc_data_structures",
+    "dep:rustc_error_messages",
     "dep:rustc_macros",
     "dep:rustc_serialize",
 ]

compiler/rustc_structures/src/limit.rs

@@ -56,3 +56,13 @@ impl Mul<usize> for Limit {
         Limit::new(self.0 * rhs)
     }
 }
+
+#[cfg(feature = "nightly")]
+impl rustc_error_messages::IntoDiagArg for Limit {
+    fn into_diag_arg(
+        self,
+        _: &mut Option<std::path::PathBuf>,
+    ) -> rustc_error_messages::DiagArgValue {
+        self.0.into_diag_arg(&mut None)
+    }
+}