From 122520d80cde154036ed9c0b9a0aacf423b121ed Mon Sep 17 00:00:00 2001 From: Nicholas Nethercote Date: Wed, 3 Jan 2024 12:17:35 +1100 Subject: [PATCH] Make `DiagnosticBuilder::emit` consuming. This works for most of its call sites. This is nice, because `emit` very much makes sense as a consuming operation -- indeed, `DiagnosticBuilderState` exists to ensure no diagnostic is emitted twice, but it uses runtime checks. For the small number of call sites where a consuming emit doesn't work, the commit adds `DiagnosticBuilder::emit_without_consuming`. (This will be removed in subsequent commits.) Likewise, `emit_unless` becomes consuming. And `delay_as_bug` becomes consuming, while `delay_as_bug_without_consuming` is added (which will also be removed in subsequent commits.) All this requires significant changes to `DiagnosticBuilder`'s chaining methods. Currently `DiagnosticBuilder` method chaining uses a non-consuming `&mut self -> &mut Self` style, which allows chaining to be used when the chain ends in `emit()`, like so: ``` struct_err(msg).span(span).emit(); ``` But it doesn't work when producing a `DiagnosticBuilder` value, requiring this: ``` let mut err = self.struct_err(msg); err.span(span); err ``` This style of chaining won't work with consuming `emit` though. For that, we need to use to a `self -> Self` style. That also would allow `DiagnosticBuilder` production to be chained, e.g.: ``` self.struct_err(msg).span(span) ``` However, removing the `&mut self -> &mut Self` style would require that individual modifications of a `DiagnosticBuilder` go from this: ``` err.span(span); ``` to this: ``` err = err.span(span); ``` There are *many* such places. I have a high tolerance for tedious refactorings, but even I gave up after a long time trying to convert them all. Instead, this commit has it both ways: the existing `&mut self -> Self` chaining methods are kept, and new `self -> Self` chaining methods are added, all of which have a `_mv` suffix (short for "move"). Changes to the existing `forward!` macro lets this happen with very little additional boilerplate code. I chose to add the suffix to the new chaining methods rather than the existing ones, because the number of changes required is much smaller that way. This doubled chainging is a bit clumsy, but I think it is worthwhile because it allows a *lot* of good things to subsequently happen. In this commit, there are many `mut` qualifiers removed in places where diagnostics are emitted without being modified. In subsequent commits: - chaining can be used more, making the code more concise; - more use of chaining also permits the removal of redundant diagnostic APIs like `struct_err_with_code`, which can be replaced easily with `struct_err` + `code_mv`; - `emit_without_diagnostic` can be removed, which simplifies a lot of machinery, removing the need for `DiagnosticBuilderState`. --- clippy_config/src/msrvs.rs | 2 +- clippy_utils/src/attrs.rs | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/clippy_config/src/msrvs.rs b/clippy_config/src/msrvs.rs index 471ad73e207..76f3663f04f 100644 --- a/clippy_config/src/msrvs.rs +++ b/clippy_config/src/msrvs.rs @@ -109,7 +109,7 @@ fn parse_attr(sess: &Session, attrs: &[Attribute]) -> Option { if let Some(duplicate) = msrv_attrs.last() { sess.dcx() .struct_span_err(duplicate.span, "`clippy::msrv` is defined multiple times") - .span_note(msrv_attr.span, "first definition found here") + .span_note_mv(msrv_attr.span, "first definition found here") .emit(); } diff --git a/clippy_utils/src/attrs.rs b/clippy_utils/src/attrs.rs index db80e07ca1c..19d38903ade 100644 --- a/clippy_utils/src/attrs.rs +++ b/clippy_utils/src/attrs.rs @@ -136,7 +136,7 @@ pub fn get_unique_attr<'a>( if let Some(duplicate) = unique_attr { sess.dcx() .struct_span_err(attr.span, format!("`{name}` is defined multiple times")) - .span_note(duplicate.span, "first definition found here") + .span_note_mv(duplicate.span, "first definition found here") .emit(); } else { unique_attr = Some(attr);