UPDATE - avoid exposing source_map methods from Handler

compiler/rustc_attr/src/builtin.rs

@@ -63,7 +63,7 @@ fn handle_errors(sess: &ParseSess, span: Span, error: AttrError) {
             sess.emit_err(session_diagnostics::MultipleStabilityLevels { span });
         }
         AttrError::UnsupportedLiteral(reason, is_bytestr) => {
-            sess.emit_err(session_diagnostics::UnsupportedLiteral { span, reason, is_bytestr });
+            sess.emit_err(session_diagnostics::UnsupportedLiteral { span, reason, is_bytestr, source_map: sess.source_map() });
         }
     }
 }

compiler/rustc_attr/src/session_diagnostics.rs

@@ -6,7 +6,7 @@ use rustc_errors::{
 };
 use rustc_macros::SessionDiagnostic;
 use rustc_session::SessionDiagnostic;
-use rustc_span::{Span, Symbol};
+use rustc_span::{Span, Symbol, source_map::SourceMap};
 
 use crate::UnsupportedLiteralReason;
 
@@ -202,13 +202,14 @@ pub(crate) struct InvalidReprHintNoValue {
 }
 
 // Error code: E0565
-pub(crate) struct UnsupportedLiteral {
+pub(crate) struct UnsupportedLiteral<'a> {
     pub span: Span,
     pub reason: UnsupportedLiteralReason,
     pub is_bytestr: bool,
+    pub source_map: &'a SourceMap,
 }
 
-impl<'a> SessionDiagnostic<'a> for UnsupportedLiteral {
+impl<'a> SessionDiagnostic<'a> for UnsupportedLiteral<'a> {
     fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
         let mut diag = handler.struct_span_err_with_code(
             self.span,
@@ -225,10 +226,8 @@ impl<'a> SessionDiagnostic<'a> for UnsupportedLiteral {
             error_code!(E0565),
         );
         if self.is_bytestr {
-            let start_point = handler.span_start_point_from_emitter(self.span).unwrap_or(self.span);
-
             diag.span_suggestion(
-                start_point,
+                self.source_map.start_point(self.span),
                 fluent::attr::unsupported_literal_suggestion,
                 "",
                 Applicability::MaybeIncorrect,

compiler/rustc_errors/src/lib.rs

@@ -1098,28 +1098,6 @@ impl Handler {
         );
         std::mem::take(&mut self.inner.borrow_mut().fulfilled_expectations)
     }
-
-    pub fn span_to_snippet_from_emitter(
-        &self,
-        span: rustc_span::Span,
-    ) -> Option<Result<String, rustc_span::SpanSnippetError>> {
-        self.inner
-            .borrow()
-            .emitter
-            .source_map()
-            .map_or_else(|| Option::None, |sm| Some(sm.span_to_snippet(span)))
-    }
-
-    pub fn span_start_point_from_emitter(
-        &self,
-        span: rustc_span::Span,
-    ) -> Option<rustc_span::Span> {
-        self.inner
-            .borrow()
-            .emitter
-            .source_map()
-            .map_or_else(|| Option::None, |sm| Some(sm.start_point(span)))
-    }
 }
 
 impl HandlerInner {

compiler/rustc_typeck/src/astconv/errors.rs

@@ -29,6 +29,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         self.tcx().sess.emit_err(MissingTypeParams {
             span,
             def_span: self.tcx().def_span(def_id),
+            source_map: self.tcx().sess.source_map(),
             missing_type_params,
             empty_generic_args,
         });

compiler/rustc_typeck/src/errors.rs

@@ -3,7 +3,7 @@ use rustc_errors::{error_code, Applicability, DiagnosticBuilder, ErrorGuaranteed
 use rustc_macros::{LintDiagnostic, SessionDiagnostic, SessionSubdiagnostic};
 use rustc_middle::ty::Ty;
 use rustc_session::SessionDiagnostic;
-use rustc_span::{symbol::Ident, Span, Symbol};
+use rustc_span::{symbol::Ident, Span, Symbol, source_map::SourceMap};
 
 #[derive(SessionDiagnostic)]
 #[diag(typeck::field_multiply_specified_in_initializer, code = "E0062")]
@@ -241,15 +241,16 @@ pub struct UnconstrainedOpaqueType {
     pub name: Symbol,
 }
 
-pub struct MissingTypeParams {
+pub struct MissingTypeParams<'a> {
     pub span: Span,
     pub def_span: Span,
     pub missing_type_params: Vec<Symbol>,
     pub empty_generic_args: bool,
+    pub source_map: &'a SourceMap,
 }
 
 // Manual implementation of `SessionDiagnostic` to be able to call `span_to_snippet`.
-impl<'a> SessionDiagnostic<'a> for MissingTypeParams {
+impl<'a> SessionDiagnostic<'a> for MissingTypeParams<'a> {
     fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
         let mut err = handler.struct_span_err_with_code(
             self.span,
@@ -269,8 +270,8 @@ impl<'a> SessionDiagnostic<'a> for MissingTypeParams {
         err.span_label(self.def_span, rustc_errors::fluent::typeck::label);
 
         let mut suggested = false;
-        if let (Some(Ok(snippet)), true) = (
-            handler.span_to_snippet_from_emitter(self.span),
+        if let (Ok(snippet), true) = (
+            self.source_map.span_to_snippet(self.span),
             // Don't suggest setting the type params if there are some already: the order is
             // tricky to get right and the user will already know what the syntax is.
             self.empty_generic_args,