Rename some arguments.

`sess` is a terribly misleading name for a `Handler`! This confused me
for a bit.

Author: nnethercote

compiler/rustc_codegen_gcc/src/errors.rs

@@ -111,8 +111,8 @@ pub(crate) struct TargetFeatureDisableOrEnable<'a> {
 pub(crate) struct MissingFeatures;
 
 impl IntoDiagnostic<'_, ErrorGuaranteed> for TargetFeatureDisableOrEnable<'_> {
-    fn into_diagnostic(self, sess: &'_ Handler) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
-        let mut diag = sess.struct_err(fluent::codegen_gcc_target_feature_disable_or_enable);
+    fn into_diagnostic(self, handler: &'_ Handler) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+        let mut diag = handler.struct_err(fluent::codegen_gcc_target_feature_disable_or_enable);
         if let Some(span) = self.span {
             diag.set_span(span);
         };

compiler/rustc_codegen_llvm/src/errors.rs

@@ -102,12 +102,12 @@ pub(crate) struct DynamicLinkingWithLTO;
 pub(crate) struct ParseTargetMachineConfig<'a>(pub LlvmError<'a>);
 
 impl<EM: EmissionGuarantee> IntoDiagnostic<'_, EM> for ParseTargetMachineConfig<'_> {
-    fn into_diagnostic(self, sess: &'_ Handler) -> DiagnosticBuilder<'_, EM> {
-        let diag: DiagnosticBuilder<'_, EM> = self.0.into_diagnostic(sess);
+    fn into_diagnostic(self, handler: &'_ Handler) -> DiagnosticBuilder<'_, EM> {
+        let diag: DiagnosticBuilder<'_, EM> = self.0.into_diagnostic(handler);
         let (message, _) = diag.styled_message().first().expect("`LlvmError` with no message");
-        let message = sess.eagerly_translate_to_string(message.clone(), diag.args());
+        let message = handler.eagerly_translate_to_string(message.clone(), diag.args());
 
-        let mut diag = sess.struct_diagnostic(fluent::codegen_llvm_parse_target_machine_config);
+        let mut diag = handler.struct_diagnostic(fluent::codegen_llvm_parse_target_machine_config);
         diag.set_arg("error", message);
         diag
     }
@@ -124,8 +124,8 @@ pub(crate) struct TargetFeatureDisableOrEnable<'a> {
 pub(crate) struct MissingFeatures;
 
 impl IntoDiagnostic<'_, ErrorGuaranteed> for TargetFeatureDisableOrEnable<'_> {
-    fn into_diagnostic(self, sess: &'_ Handler) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
-        let mut diag = sess.struct_err(fluent::codegen_llvm_target_feature_disable_or_enable);
+    fn into_diagnostic(self, handler: &'_ Handler) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+        let mut diag = handler.struct_err(fluent::codegen_llvm_target_feature_disable_or_enable);
         if let Some(span) = self.span {
             diag.set_span(span);
         };
@@ -184,7 +184,7 @@ pub enum LlvmError<'a> {
 pub(crate) struct WithLlvmError<'a>(pub LlvmError<'a>, pub String);
 
 impl<EM: EmissionGuarantee> IntoDiagnostic<'_, EM> for WithLlvmError<'_> {
-    fn into_diagnostic(self, sess: &'_ Handler) -> DiagnosticBuilder<'_, EM> {
+    fn into_diagnostic(self, handler: &'_ Handler) -> DiagnosticBuilder<'_, EM> {
         use LlvmError::*;
         let msg_with_llvm_err = match &self.0 {
             WriteOutput { .. } => fluent::codegen_llvm_write_output_with_llvm_err,
@@ -201,7 +201,7 @@ impl<EM: EmissionGuarantee> IntoDiagnostic<'_, EM> for WithLlvmError<'_> {
             PrepareThinLtoModule => fluent::codegen_llvm_prepare_thin_lto_module_with_llvm_err,
             ParseBitcode => fluent::codegen_llvm_parse_bitcode_with_llvm_err,
         };
-        let mut diag = self.0.into_diagnostic(sess);
+        let mut diag = self.0.into_diagnostic(handler);
         diag.set_primary_message(msg_with_llvm_err);
         diag.set_arg("llvm_err", self.1);
         diag