Use diagnostic API on Session

src/librustc/session/mod.rs

@@ -965,7 +965,7 @@ pub fn codegen_units(&self) -> usize {
     }
 
     pub fn teach(&self, code: &DiagnosticId) -> bool {
-        self.opts.debugging_opts.teach && self.parse_sess.span_diagnostic.must_teach(code)
+        self.opts.debugging_opts.teach && self.diagnostic().must_teach(code)
     }
 
     /// Are we allowed to use features from the Rust 2018 edition?

src/librustc_codegen_utils/codegen_backend.rs

@@ -116,7 +116,7 @@ fn init(&self, sess: &Session) {
             match *cty {
                 CrateType::Rlib | CrateType::Dylib | CrateType::Executable => {},
                 _ => {
-                    sess.parse_sess.span_diagnostic.warn(
+                    sess.diagnostic().warn(
                         &format!("LLVM unsupported, so output type {} is not supported", cty)
                     );
                 },

src/librustc_driver/driver.rs

@@ -1133,7 +1133,7 @@ pub fn phase_2_configure_and_expand_inner<'a, 'b: 'a, F>(
     // Unresolved macros might be due to mistyped `#[macro_use]`,
     // so abort after checking for unknown attributes. (#49074)
     if resolver.found_unresolved_macro {
-        sess.parse_sess.span_diagnostic.abort_if_errors();
+        sess.diagnostic().abort_if_errors();
     }
 
     // Lower ast -> hir.

src/librustc_passes/ast_validation.rs

@@ -32,7 +32,7 @@ struct AstValidator<'a> {
 
 impl<'a> AstValidator<'a> {
     fn err_handler(&self) -> &errors::Handler {
-        &self.session.parse_sess.span_diagnostic
+        &self.session.diagnostic()
     }
 
     fn check_lifetime(&self, ident: Ident) {