span: move `MultiSpan`

`MultiSpan` contains labels, which are more complicated with the
introduction of diagnostic translation and will use types from
`rustc_errors` - however, `rustc_errors` depends on `rustc_span` so
`rustc_span` cannot use types like `DiagnosticMessage` without
dependency cycles. Introduce a new `rustc_error_messages` crate that can
contain `DiagnosticMessage` and `MultiSpan`.

Signed-off-by: David Wood <david.wood@huawei.com>

4 files changed, 8 insertions, 8 deletions

diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index d43c661dda6..fd414dd5bc7 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -31,7 +31,7 @@ use rustc_ast::{self as ast, *};
 use rustc_ast_pretty::pprust::{self, expr_to_string};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::stack::ensure_sufficient_stack;
-use rustc_errors::{Applicability, Diagnostic, DiagnosticStyledString};
+use rustc_errors::{Applicability, Diagnostic, DiagnosticStyledString, MultiSpan};
 use rustc_feature::{deprecated_attributes, AttributeGate, BuiltinAttribute, GateIssue, Stability};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
@@ -49,7 +49,7 @@ use rustc_session::lint::{BuiltinLintDiagnostics, FutureIncompatibilityReason};
 use rustc_span::edition::Edition;
 use rustc_span::source_map::Spanned;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use rustc_span::{BytePos, InnerSpan, MultiSpan, Span};
+use rustc_span::{BytePos, InnerSpan, Span};
 use rustc_target::abi::VariantIdx;
 use rustc_trait_selection::traits::{self, misc::can_type_implement_copy};
 
diff --git a/compiler/rustc_lint/src/context.rs b/compiler/rustc_lint/src/context.rs
index 882fa4496ca..3600b6ad212 100644
--- a/compiler/rustc_lint/src/context.rs
+++ b/compiler/rustc_lint/src/context.rs
@@ -21,7 +21,7 @@ use crate::passes::{EarlyLintPassObject, LateLintPassObject};
 use rustc_ast::util::unicode::TEXT_FLOW_CONTROL_CHARS;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync;
-use rustc_errors::{struct_span_err, Applicability, SuggestionStyle};
+use rustc_errors::{struct_span_err, Applicability, MultiSpan, SuggestionStyle};
 use rustc_hir as hir;
 use rustc_hir::def::Res;
 use rustc_hir::def_id::{CrateNum, DefId};
@@ -38,7 +38,7 @@ use rustc_session::lint::{FutureIncompatibleInfo, Level, Lint, LintBuffer, LintI
 use rustc_session::Session;
 use rustc_span::lev_distance::find_best_match_for_name;
 use rustc_span::symbol::{sym, Ident, Symbol};
-use rustc_span::{BytePos, MultiSpan, Span, DUMMY_SP};
+use rustc_span::{BytePos, Span, DUMMY_SP};
 use rustc_target::abi;
 use tracing::debug;
 
diff --git a/compiler/rustc_lint/src/levels.rs b/compiler/rustc_lint/src/levels.rs
index 99a5720832e..01f1d1e79ac 100644
--- a/compiler/rustc_lint/src/levels.rs
+++ b/compiler/rustc_lint/src/levels.rs
@@ -3,7 +3,7 @@ use crate::late::unerased_lint_store;
 use rustc_ast as ast;
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashMap;
-use rustc_errors::{struct_span_err, Applicability, Diagnostic};
+use rustc_errors::{struct_span_err, Applicability, Diagnostic, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::{intravisit, HirId};
 use rustc_middle::hir::nested_filter;
@@ -20,7 +20,7 @@ use rustc_session::lint::{
 use rustc_session::parse::{add_feature_diagnostics, feature_err};
 use rustc_session::Session;
 use rustc_span::symbol::{sym, Symbol};
-use rustc_span::{source_map::MultiSpan, Span, DUMMY_SP};
+use rustc_span::{Span, DUMMY_SP};
 use tracing::debug;
 
 fn lint_levels(tcx: TyCtxt<'_>, (): ()) -> LintLevelMap {
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index 91b72f1d2b1..494bdaa1e2b 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -3,7 +3,7 @@ use crate::{EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext}
 use rustc_ast as ast;
 use rustc_ast::util::{classify, parser};
 use rustc_ast::{ExprKind, StmtKind};
-use rustc_errors::{pluralize, Applicability};
+use rustc_errors::{pluralize, Applicability, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::DefId;
@@ -11,7 +11,7 @@ use rustc_middle::ty::adjustment;
 use rustc_middle::ty::{self, Ty};
 use rustc_span::symbol::Symbol;
 use rustc_span::symbol::{kw, sym};
-use rustc_span::{BytePos, MultiSpan, Span, DUMMY_SP};
+use rustc_span::{BytePos, Span, DUMMY_SP};
 
 declare_lint! {
     /// The `unused_must_use` lint detects unused result of a type flagged as