Auto merge of #119606 - nnethercote:consuming-emit, r=oli-obk

Consuming `emit`

This PR makes `DiagnosticBuilder::emit` consuming, i.e. take `self` instead of `&mut self`. This is good because it doesn't make sense to emit a diagnostic twice.

This requires some changes to `DiagnosticBuilder` method changing -- every existing non-consuming chaining method gets a new consuming partner with a `_mv` suffix -- but permits a host of beneficial follow-up changes: more concise code through more chaining, removal of redundant diagnostic construction API methods, and removal of machinery to track the possibility of a diagnostic being emitted multiple times.

r? `@compiler-errors`

2 files changed, 2 insertions, 2 deletions

diff --git a/compiler/rustc_interface/src/callbacks.rs b/compiler/rustc_interface/src/callbacks.rs
index ef00ced67ff..7458be2c86d 100644
--- a/compiler/rustc_interface/src/callbacks.rs
+++ b/compiler/rustc_interface/src/callbacks.rs
@@ -29,7 +29,7 @@ fn track_span_parent(def_id: rustc_span::def_id::LocalDefId) {
 /// This is a callback from `rustc_errors` as it cannot access the implicit state
 /// in `rustc_middle` otherwise. It is used when diagnostic messages are
 /// emitted and stores them in the current query, if there is one.
-fn track_diagnostic(diagnostic: &mut Diagnostic, f: &mut dyn FnMut(&mut Diagnostic)) {
+fn track_diagnostic(diagnostic: Diagnostic, f: &mut dyn FnMut(Diagnostic)) {
     tls::with_context_opt(|icx| {
         if let Some(icx) = icx {
             if let Some(diagnostics) = icx.diagnostics {
diff --git a/compiler/rustc_interface/src/queries.rs b/compiler/rustc_interface/src/queries.rs
index 07bbe78dc2d..9da806e0779 100644
--- a/compiler/rustc_interface/src/queries.rs
+++ b/compiler/rustc_interface/src/queries.rs
@@ -108,7 +108,7 @@ impl<'tcx> Queries<'tcx> {
 
     pub fn parse(&self) -> Result<QueryResult<'_, ast::Crate>> {
         self.parse.compute(|| {
-            passes::parse(&self.compiler.sess).map_err(|mut parse_error| parse_error.emit())
+            passes::parse(&self.compiler.sess).map_err(|parse_error| parse_error.emit())
         })
     }