From 3a5f28f7e821a2325e9dbdb4ff40cd9ff417f065 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Mon, 18 Dec 2023 16:22:45 +1100
Subject: [PATCH] Remove `struct_diagnostic` and `G::make_diagnostic_builder`.

`EmissionGuarantee` no longer determines the error level, the `create_*`
functions do.
---
 .../rustc_errors/src/diagnostic_builder.rs    | 50 -------------------
 compiler/rustc_errors/src/lib.rs              | 15 ------
 2 files changed, 65 deletions(-)

diff --git a/compiler/rustc_errors/src/diagnostic_builder.rs b/compiler/rustc_errors/src/diagnostic_builder.rs
index 0079fa8b995..59e5c1f352f 100644
--- a/compiler/rustc_errors/src/diagnostic_builder.rs
+++ b/compiler/rustc_errors/src/diagnostic_builder.rs
@@ -106,13 +106,6 @@ pub trait EmissionGuarantee: Sized {
     /// of `Self` without actually performing the emission.
     #[track_caller]
     fn diagnostic_builder_emit_producing_guarantee(db: &mut DiagnosticBuilder<'_, Self>) -> Self;
-
-    /// Creates a new `DiagnosticBuilder` that will return this type of guarantee.
-    #[track_caller]
-    fn make_diagnostic_builder(
-        dcx: &DiagCtxt,
-        msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, Self>;
 }
 
 impl<'a> DiagnosticBuilder<'a, ErrorGuaranteed> {
@@ -163,14 +156,6 @@ impl EmissionGuarantee for ErrorGuaranteed {
             }
         }
     }
-
-    #[track_caller]
-    fn make_diagnostic_builder(
-        dcx: &DiagCtxt,
-        msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, Self> {
-        DiagnosticBuilder::new(dcx, Level::Error { lint: false }, msg)
-    }
 }
 
 // FIXME(eddyb) should there be a `Option<ErrorGuaranteed>` impl as well?
@@ -187,13 +172,6 @@ impl EmissionGuarantee for () {
             DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation => {}
         }
     }
-
-    fn make_diagnostic_builder(
-        dcx: &DiagCtxt,
-        msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, Self> {
-        DiagnosticBuilder::new(dcx, Level::Warning(None), msg)
-    }
 }
 
 /// Marker type which enables implementation of `create_note` and `emit_note` functions for
@@ -215,13 +193,6 @@ impl EmissionGuarantee for Noted {
 
         Noted
     }
-
-    fn make_diagnostic_builder(
-        dcx: &DiagCtxt,
-        msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, Self> {
-        DiagnosticBuilder::new(dcx, Level::Note, msg)
-    }
 }
 
 /// Marker type which enables implementation of `create_bug` and `emit_bug` functions for
@@ -244,13 +215,6 @@ impl EmissionGuarantee for Bug {
         // Then panic. No need to return the marker type.
         panic::panic_any(ExplicitBug);
     }
-
-    fn make_diagnostic_builder(
-        dcx: &DiagCtxt,
-        msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, Self> {
-        DiagnosticBuilder::new(dcx, Level::Bug, msg)
-    }
 }
 
 impl EmissionGuarantee for ! {
@@ -268,13 +232,6 @@ impl EmissionGuarantee for ! {
         // Then fatally error, returning `!`
         crate::FatalError.raise()
     }
-
-    fn make_diagnostic_builder(
-        dcx: &DiagCtxt,
-        msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, Self> {
-        DiagnosticBuilder::new(dcx, Level::Fatal, msg)
-    }
 }
 
 impl EmissionGuarantee for rustc_span::fatal_error::FatalError {
@@ -292,13 +249,6 @@ impl EmissionGuarantee for rustc_span::fatal_error::FatalError {
         // Then fatally error..
         rustc_span::fatal_error::FatalError
     }
-
-    fn make_diagnostic_builder(
-        dcx: &DiagCtxt,
-        msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, Self> {
-        DiagnosticBuilder::new(dcx, Level::Fatal, msg)
-    }
 }
 
 /// In general, the `DiagnosticBuilder` uses deref to allow access to
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 5027f63a970..a86a12506ad 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -722,21 +722,6 @@ impl DiagCtxt {
         self.inner.borrow_mut().emit_stashed_diagnostics()
     }
 
-    /// Construct a builder with the `msg` at the level appropriate for the
-    /// specific `EmissionGuarantee`.
-    ///
-    /// Note: this is necessary for `derive(Diagnostic)`, but shouldn't be used
-    /// outside of that. Instead use `struct_err`, `struct_warn`, etc., which
-    /// make the diagnostic kind clearer.
-    #[rustc_lint_diagnostics]
-    #[track_caller]
-    pub fn struct_diagnostic<G: EmissionGuarantee>(
-        &self,
-        msg: impl Into<DiagnosticMessage>,
-    ) -> DiagnosticBuilder<'_, G> {
-        G::make_diagnostic_builder(self, msg)
-    }
-
     /// Construct a builder at the `Warning` level at the given `span` and with the `msg`.
     ///
     /// Attempting to `.emit()` the builder will only emit if either: