Generate lint diagnostic message from BuiltinLintDiag

Translation of the lint message happens when the actual diagnostic is
created, not when the lint is buffered. Generating the message from
BuiltinLintDiag ensures that all required data to construct the message
is preserved in the LintBuffer, eventually allowing the messages to be
moved to fluent.

Remove the `msg` field from BufferedEarlyLint, it is either generated
from the data in the BuiltinLintDiag or stored inside
BuiltinLintDiag::Normal.

1 files changed, 7 insertions, 16 deletions

diff --git a/compiler/rustc_resolve/src/check_unused.rs b/compiler/rustc_resolve/src/check_unused.rs
index 180e7f6def3..2a8eb940ccf 100644
--- a/compiler/rustc_resolve/src/check_unused.rs
+++ b/compiler/rustc_resolve/src/check_unused.rs
@@ -32,7 +32,7 @@ use rustc_ast as ast;
 use rustc_ast::visit::{self, Visitor};
 use rustc_data_structures::fx::{FxHashMap, FxIndexMap, FxIndexSet};
 use rustc_data_structures::unord::UnordSet;
-use rustc_errors::{pluralize, MultiSpan};
+use rustc_errors::MultiSpan;
 use rustc_hir::def::{DefKind, Res};
 use rustc_session::lint::builtin::{MACRO_USE_EXTERN_CRATE, UNUSED_EXTERN_CRATES};
 use rustc_session::lint::builtin::{UNUSED_IMPORTS, UNUSED_QUALIFICATIONS};
@@ -155,7 +155,6 @@ impl<'a, 'b, 'tcx> UnusedImportCheckVisitor<'a, 'b, 'tcx> {
                         UNUSED_EXTERN_CRATES,
                         extern_crate.id,
                         span,
-                        "unused extern crate",
                         BuiltinLintDiag::UnusedExternCrate {
                             removal_span: extern_crate.span_with_attributes,
                         },
@@ -208,7 +207,6 @@ impl<'a, 'b, 'tcx> UnusedImportCheckVisitor<'a, 'b, 'tcx> {
                 UNUSED_EXTERN_CRATES,
                 extern_crate.id,
                 extern_crate.span,
-                "`extern crate` is not idiomatic in the new edition",
                 BuiltinLintDiag::ExternCrateNotIdiomatic { vis_span, ident_span },
             );
         }
@@ -459,16 +457,6 @@ impl Resolver<'_, '_> {
                 .collect::<Vec<String>>();
             span_snippets.sort();
 
-            let msg = format!(
-                "unused import{}{}",
-                pluralize!(ms.primary_spans().len()),
-                if !span_snippets.is_empty() {
-                    format!(": {}", span_snippets.join(", "))
-                } else {
-                    String::new()
-                }
-            );
-
             let fix_msg = if fixes.len() == 1 && fixes[0].0 == unused.item_span {
                 "remove the whole `use` item"
             } else if ms.primary_spans().len() > 1 {
@@ -505,8 +493,12 @@ impl Resolver<'_, '_> {
                 UNUSED_IMPORTS,
                 unused.use_tree_id,
                 ms,
-                msg,
-                BuiltinLintDiag::UnusedImports(fix_msg.into(), fixes, test_module_span),
+                BuiltinLintDiag::UnusedImports {
+                    fix_msg: fix_msg.into(),
+                    fixes,
+                    test_module_span,
+                    span_snippets,
+                },
             );
         }
 
@@ -556,7 +548,6 @@ impl Resolver<'_, '_> {
                 UNUSED_QUALIFICATIONS,
                 unn_qua.node_id,
                 unn_qua.path_span,
-                "unnecessary qualification",
                 BuiltinLintDiag::UnusedQualifications { removal_span: unn_qua.removal_span },
             );
         }