Rollup merge of #65470 - traxys:fix_65401, r=michaelwoerister

Don't hide ICEs from previous incremental compiles

I think this fixes #65401, the compiler does not fail to ICE after the first compilation, tested on the last snippet of [this comment](https://github.com/rust-lang/rust/issues/63154#issuecomment-541592381).
I am not very sure of the fix as I don't understand much of the structure of the compiler.

src/librustc/session/mod.rs

@@ -312,6 +312,9 @@ pub fn err_count(&self) -> usize {
     pub fn has_errors(&self) -> bool {
         self.diagnostic().has_errors()
     }
+    pub fn has_errors_or_delayed_span_bugs(&self) -> bool {
+        self.diagnostic().has_errors_or_delayed_span_bugs()
+    }
     pub fn abort_if_errors(&self) {
         self.diagnostic().abort_if_errors();
     }

src/librustc_errors/lib.rs

@@ -704,6 +704,9 @@ pub fn err_count(&self) -> usize {
     pub fn has_errors(&self) -> bool {
         self.inner.borrow().has_errors()
     }
+    pub fn has_errors_or_delayed_span_bugs(&self) -> bool {
+        self.inner.borrow().has_errors_or_delayed_span_bugs()
+    }
 
     pub fn print_error_count(&self, registry: &Registry) {
         self.inner.borrow_mut().print_error_count(registry)
@@ -862,6 +865,9 @@ fn err_count(&self) -> usize {
     fn has_errors(&self) -> bool {
         self.err_count() > 0
     }
+    fn has_errors_or_delayed_span_bugs(&self) -> bool {
+        self.has_errors() || !self.delayed_span_bugs.is_empty()
+    }
 
     fn abort_if_errors_and_should_abort(&mut self) {
         self.emit_stashed_diagnostics();

src/librustc_incremental/persist/fs.rs

@@ -307,7 +307,7 @@ pub fn finalize_session_directory(sess: &Session, svh: Svh) {
 
     let incr_comp_session_dir: PathBuf = sess.incr_comp_session_dir().clone();
 
-    if sess.has_errors() {
+    if sess.has_errors_or_delayed_span_bugs() {
         // If there have been any errors during compilation, we don't want to
         // publish this session directory. Rather, we'll just delete it.
 

src/librustc_incremental/persist/save.rs

@@ -22,6 +22,10 @@ pub fn save_dep_graph(tcx: TyCtxt<'_>) {
         if sess.opts.incremental.is_none() {
             return;
         }
+        // This is going to be deleted in finalize_session_directory, so let's not create it
+        if sess.has_errors_or_delayed_span_bugs() {
+            return;
+        }
 
         let query_cache_path = query_cache_path(sess);
         let dep_graph_path = dep_graph_path(sess);
@@ -60,6 +64,10 @@ pub fn save_work_product_index(sess: &Session,
     if sess.opts.incremental.is_none() {
         return;
     }
+    // This is going to be deleted in finalize_session_directory, so let's not create it
+    if sess.has_errors_or_delayed_span_bugs() {
+            return;
+    }
 
     debug!("save_work_product_index()");
     dep_graph.assert_ignored();