diff --git a/src/librustc/dep_graph/graph.rs b/src/librustc/dep_graph/graph.rs
index de57edc1251a2..8a2f79e6793c0 100644
--- a/src/librustc/dep_graph/graph.rs
+++ b/src/librustc/dep_graph/graph.rs
@@ -292,17 +292,28 @@ impl DepGraph {
                 task_deps.map(|lock| lock.into_inner()),
             );
 
+            let print_status = cfg!(debug_assertions) && hcx.sess().opts.debugging_opts.dep_tasks;
+
             // Determine the color of the new DepNode.
             if let Some(prev_index) = data.previous.node_to_index_opt(&key) {
                 let prev_fingerprint = data.previous.fingerprint_by_index(prev_index);
 
                 let color = if let Some(current_fingerprint) = current_fingerprint {
                     if current_fingerprint == prev_fingerprint {
+                        if print_status {
+                            eprintln!("[task::green] {:?}", key);
+                        }
                         DepNodeColor::Green(dep_node_index)
                     } else {
+                        if print_status {
+                            eprintln!("[task::red] {:?}", key);
+                        }
                         DepNodeColor::Red
                     }
                 } else {
+                    if print_status {
+                        eprintln!("[task::unknown] {:?}", key);
+                    }
                     // Mark the node as Red if we can't hash the result
                     DepNodeColor::Red
                 };
@@ -312,6 +323,10 @@ impl DepGraph {
                             insertion for {:?}", key);
 
                 data.colors.insert(prev_index, color);
+            } else {
+                if print_status {
+                    eprintln!("[task::new] {:?}", key);
+                }
             }
 
             (result, dep_node_index)
diff --git a/src/librustc/infer/error_reporting/nice_region_error/mod.rs b/src/librustc/infer/error_reporting/nice_region_error/mod.rs
index dad1e3ba80da3..d995fe92337c4 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/mod.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/mod.rs
@@ -1,9 +1,10 @@
 use crate::infer::InferCtxt;
 use crate::infer::lexical_region_resolve::RegionResolutionError;
 use crate::infer::lexical_region_resolve::RegionResolutionError::*;
-use syntax::source_map::Span;
 use crate::ty::{self, TyCtxt};
 use crate::util::common::ErrorReported;
+use errors::DiagnosticBuilder;
+use syntax::source_map::Span;
 
 mod different_lifetimes;
 mod find_anon_type;
@@ -59,7 +60,7 @@ impl<'cx, 'gcx, 'tcx> NiceRegionError<'cx, 'gcx, 'tcx> {
         self.infcx.tcx
     }
 
-    pub fn try_report_from_nll(&self) -> Option<ErrorReported> {
+    pub fn try_report_from_nll(&self) -> Option<DiagnosticBuilder<'cx>> {
         // Due to the improved diagnostics returned by the MIR borrow checker, only a subset of
         // the nice region errors are required when running under the MIR borrow checker.
         self.try_report_named_anon_conflict()
@@ -68,6 +69,7 @@ impl<'cx, 'gcx, 'tcx> NiceRegionError<'cx, 'gcx, 'tcx> {
 
     pub fn try_report(&self) -> Option<ErrorReported> {
         self.try_report_from_nll()
+            .map(|mut diag| { diag.emit(); ErrorReported })
             .or_else(|| self.try_report_anon_anon_conflict())
             .or_else(|| self.try_report_outlives_closure())
             .or_else(|| self.try_report_static_impl_trait())
diff --git a/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs b/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs
index b10af400f2b6c..3821484d38e5f 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs
@@ -2,13 +2,12 @@
 //! where one region is named and the other is anonymous.
 use crate::infer::error_reporting::nice_region_error::NiceRegionError;
 use crate::ty;
-use crate::util::common::ErrorReported;
-use errors::Applicability;
+use errors::{Applicability, DiagnosticBuilder};
 
 impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
     /// When given a `ConcreteFailure` for a function with arguments containing a named region and
     /// an anonymous region, emit an descriptive diagnostic error.
-    pub(super) fn try_report_named_anon_conflict(&self) -> Option<ErrorReported> {
+    pub(super) fn try_report_named_anon_conflict(&self) -> Option<DiagnosticBuilder<'a>> {
         let (span, sub, sup) = self.get_regions();
 
         debug!(
@@ -96,21 +95,23 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
             ("parameter type".to_owned(), "type".to_owned())
         };
 
-        struct_span_err!(
+        let mut diag = struct_span_err!(
             self.tcx().sess,
             span,
             E0621,
             "explicit lifetime required in {}",
             error_var
-        ).span_suggestion(
-            new_ty_span,
-            &format!("add explicit lifetime `{}` to {}", named, span_label_var),
-            new_ty.to_string(),
-            Applicability::Unspecified,
-        )
-        .span_label(span, format!("lifetime `{}` required", named))
-        .emit();
-        return Some(ErrorReported);
+        );
+
+        diag.span_suggestion(
+                new_ty_span,
+                &format!("add explicit lifetime `{}` to {}", named, span_label_var),
+                new_ty.to_string(),
+                Applicability::Unspecified,
+            )
+            .span_label(span, format!("lifetime `{}` required", named));
+
+        Some(diag)
     }
 
     // This method returns whether the given Region is Named
diff --git a/src/librustc/infer/error_reporting/nice_region_error/placeholder_error.rs b/src/librustc/infer/error_reporting/nice_region_error/placeholder_error.rs
index 843fa8b0182e2..3b2fb7d41008e 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/placeholder_error.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/placeholder_error.rs
@@ -8,13 +8,12 @@ use crate::traits::{ObligationCause, ObligationCauseCode};
 use crate::ty;
 use crate::ty::error::ExpectedFound;
 use crate::ty::subst::Substs;
-use crate::util::common::ErrorReported;
 use crate::util::ppaux::RegionHighlightMode;
 
 impl NiceRegionError<'me, 'gcx, 'tcx> {
     /// When given a `ConcreteFailure` for a function with arguments containing a named region and
     /// an anonymous region, emit a descriptive diagnostic error.
-    pub(super) fn try_report_placeholder_conflict(&self) -> Option<ErrorReported> {
+    pub(super) fn try_report_placeholder_conflict(&self) -> Option<DiagnosticBuilder<'me>> {
         match &self.error {
             ///////////////////////////////////////////////////////////////////////////
             // NB. The ordering of cases in this match is very
@@ -178,7 +177,7 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
         trait_def_id: DefId,
         expected_substs: &'tcx Substs<'tcx>,
         actual_substs: &'tcx Substs<'tcx>,
-    ) -> ErrorReported {
+    ) -> DiagnosticBuilder<'me> {
         debug!(
             "try_report_placeholders_trait(\
              vid={:?}, \
@@ -295,8 +294,7 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
             any_self_ty_has_vid,
         );
 
-        err.emit();
-        ErrorReported
+        err
     }
 
     /// Add notes with details about the expected and actual trait refs, with attention to cases
diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs
index 22b1c3f18acb2..65da458efbfff 100644
--- a/src/librustc/session/config.rs
+++ b/src/librustc/session/config.rs
@@ -1237,6 +1237,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "show extended diagnostic help"),
     continue_parse_after_error: bool = (false, parse_bool, [TRACKED],
         "attempt to recover from parse errors (experimental)"),
+    dep_tasks: bool = (false, parse_bool, [UNTRACKED],
+        "print tasks that execute and the color their dep node gets (requires debug build)"),
     incremental: Option<String> = (None, parse_opt_string, [UNTRACKED],
         "enable incremental compilation (experimental)"),
     incremental_queries: bool = (true, parse_bool, [UNTRACKED],
diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs
index 58bd4782b2143..833785f04076c 100644
--- a/src/librustc/session/mod.rs
+++ b/src/librustc/session/mod.rs
@@ -9,7 +9,7 @@ use crate::lint;
 use crate::lint::builtin::BuiltinLintDiagnostics;
 use crate::middle::allocator::AllocatorKind;
 use crate::middle::dependency_format;
-use crate::session::config::{OutputType, Lto};
+use crate::session::config::OutputType;
 use crate::session::search_paths::{PathKind, SearchPath};
 use crate::util::nodemap::{FxHashMap, FxHashSet};
 use crate::util::common::{duration_to_secs_str, ErrorReported};
@@ -1246,20 +1246,6 @@ pub fn build_session_(
 // If it is useful to have a Session available already for validating a
 // commandline argument, you can do so here.
 fn validate_commandline_args_with_session_available(sess: &Session) {
-
-    if sess.opts.incremental.is_some() {
-        match sess.lto() {
-            Lto::Thin |
-            Lto::Fat => {
-                sess.err("can't perform LTO when compiling incrementally");
-            }
-            Lto::ThinLocal |
-            Lto::No => {
-                // This is fine
-            }
-        }
-    }
-
     // Since we don't know if code in an rlib will be linked to statically or
     // dynamically downstream, rustc generates `__imp_` symbols that help the
     // MSVC linker deal with this lack of knowledge (#27438). Unfortunately,
diff --git a/src/librustc/ty/query/plumbing.rs b/src/librustc/ty/query/plumbing.rs
index 233aff9de243f..19b39be8a4ddf 100644
--- a/src/librustc/ty/query/plumbing.rs
+++ b/src/librustc/ty/query/plumbing.rs
@@ -124,7 +124,15 @@ impl<'a, 'tcx, Q: QueryDescription<'tcx>> JobOwner<'a, 'tcx, Q> {
             let job = match lock.active.entry((*key).clone()) {
                 Entry::Occupied(entry) => {
                     match *entry.get() {
-                        QueryResult::Started(ref job) => job.clone(),
+                        QueryResult::Started(ref job) => {
+                            //For parallel queries, we'll block and wait until the query running
+                            //in another thread has completed. Record how long we wait in the
+                            //self-profiler
+                            #[cfg(parallel_compiler)]
+                            tcx.sess.profiler(|p| p.query_blocked_start(Q::NAME, Q::CATEGORY));
+
+                            job.clone()
+                        },
                         QueryResult::Poisoned => FatalError.raise(),
                     }
                 }
@@ -160,7 +168,10 @@ impl<'a, 'tcx, Q: QueryDescription<'tcx>> JobOwner<'a, 'tcx, Q> {
             // thread
             #[cfg(parallel_compiler)]
             {
-                if let Err(cycle) = job.r#await(tcx, span) {
+                let result = job.r#await(tcx, span);
+                tcx.sess.profiler(|p| p.query_blocked_end(Q::NAME, Q::CATEGORY));
+
+                if let Err(cycle) = result {
                     return TryGetJob::JobCompleted(Err(cycle));
                 }
             }
@@ -441,7 +452,9 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         // First we try to load the result from the on-disk cache
         let result = if Q::cache_on_disk(self.global_tcx(), key.clone()) &&
                         self.sess.opts.debugging_opts.incremental_queries {
+            self.sess.profiler(|p| p.incremental_load_result_start(Q::NAME));
             let result = Q::try_load_from_disk(self.global_tcx(), prev_dep_node_index);
+            self.sess.profiler(|p| p.incremental_load_result_end(Q::NAME));
 
             // We always expect to find a cached result for things that
             // can be forced from DepNode.
diff --git a/src/librustc/util/profiling.rs b/src/librustc/util/profiling.rs
index f8fa01b639500..c90bd12a3100f 100644
--- a/src/librustc/util/profiling.rs
+++ b/src/librustc/util/profiling.rs
@@ -25,6 +25,10 @@ pub enum ProfilerEvent {
     GenericActivityEnd { category: ProfileCategory, time: Instant },
     QueryCacheHit { query_name: &'static str, category: ProfileCategory },
     QueryCount { query_name: &'static str, category: ProfileCategory, count: usize },
+    IncrementalLoadResultStart { query_name: &'static str, time: Instant },
+    IncrementalLoadResultEnd { query_name: &'static str, time: Instant },
+    QueryBlockedStart { query_name: &'static str, category: ProfileCategory, time: Instant },
+    QueryBlockedEnd { query_name: &'static str, category: ProfileCategory, time: Instant },
 }
 
 impl ProfilerEvent {
@@ -32,9 +36,17 @@ impl ProfilerEvent {
         use self::ProfilerEvent::*;
 
         match self {
-            QueryStart { .. } | GenericActivityStart { .. } => true,
-            QueryEnd { .. } | GenericActivityEnd { .. } |
-            QueryCacheHit { .. } | QueryCount { .. } => false,
+            QueryStart { .. } |
+            GenericActivityStart { .. } |
+            IncrementalLoadResultStart { .. } |
+            QueryBlockedStart { .. } => true,
+
+            QueryEnd { .. } |
+            GenericActivityEnd { .. } |
+            QueryCacheHit { .. } |
+            QueryCount { .. } |
+            IncrementalLoadResultEnd { .. } |
+            QueryBlockedEnd { .. } => false,
         }
     }
 }
@@ -57,12 +69,7 @@ impl CategoryResultData {
     }
 
     fn total_time(&self) -> u64 {
-        let mut total = 0;
-        for (_, time) in &self.query_times {
-            total += time;
-        }
-
-        total
+        self.query_times.iter().map(|(_, time)| time).sum()
     }
 
     fn total_cache_data(&self) -> (u64, u64) {
@@ -121,13 +128,7 @@ impl CalculatedResults {
     }
 
     fn total_time(&self) -> u64 {
-        let mut total = 0;
-
-        for (_, data) in &self.categories {
-            total += data.total_time();
-        }
-
-        total
+        self.categories.iter().map(|(_, data)| data.total_time()).sum()
     }
 
     fn with_options(mut self, opts: &Options) -> CalculatedResults {
@@ -225,6 +226,40 @@ impl SelfProfiler {
         })
     }
 
+    #[inline]
+    pub fn incremental_load_result_start(&mut self, query_name: &'static str) {
+        self.record(ProfilerEvent::IncrementalLoadResultStart {
+            query_name,
+            time: Instant::now(),
+        })
+    }
+
+    #[inline]
+    pub fn incremental_load_result_end(&mut self, query_name: &'static str) {
+        self.record(ProfilerEvent::IncrementalLoadResultEnd {
+            query_name,
+            time: Instant::now(),
+        })
+    }
+
+    #[inline]
+    pub fn query_blocked_start(&mut self, query_name: &'static str, category: ProfileCategory) {
+        self.record(ProfilerEvent::QueryBlockedStart {
+            query_name,
+            category,
+            time: Instant::now(),
+        })
+    }
+
+    #[inline]
+    pub fn query_blocked_end(&mut self, query_name: &'static str, category: ProfileCategory) {
+        self.record(ProfilerEvent::QueryBlockedEnd {
+            query_name,
+            category,
+            time: Instant::now(),
+        })
+    }
+
     #[inline]
     fn record(&mut self, event: ProfilerEvent) {
         let thread_id = std::thread::current().id();
@@ -317,6 +352,10 @@ impl SelfProfiler {
                         result_data.query_cache_stats.entry(query_name).or_insert((0, 0));
                     *totals += *count as u64;
                 },
+                //we don't summarize incremental load result events in the simple output mode
+                IncrementalLoadResultStart { .. } | IncrementalLoadResultEnd { .. } => { },
+                //we don't summarize parallel query blocking in the simple output mode
+                QueryBlockedStart { .. } | QueryBlockedEnd { .. } => { },
             }
         }
 
@@ -361,9 +400,9 @@ impl SelfProfiler {
             .unwrap();
 
         let mut categories: Vec<_> = results.categories.iter().collect();
-        categories.sort_by(|(_, data1), (_, data2)| data2.total_time().cmp(&data1.total_time()));
+        categories.sort_by_cached_key(|(_, d)| d.total_time());
 
-        for (category, data) in categories {
+        for (category, data) in categories.iter().rev() {
             let (category_hits, category_total) = data.total_cache_data();
             let category_hit_percent = calculate_percent(category_hits, category_total);
 
diff --git a/src/librustc_codegen_llvm/back/lto.rs b/src/librustc_codegen_llvm/back/lto.rs
index ac55244d8d931..fc3ab7f734a79 100644
--- a/src/librustc_codegen_llvm/back/lto.rs
+++ b/src/librustc_codegen_llvm/back/lto.rs
@@ -1,6 +1,6 @@
 use back::bytecode::{DecodedBytecode, RLIB_BYTECODE_EXTENSION};
 use rustc_codegen_ssa::back::symbol_export;
-use rustc_codegen_ssa::back::write::{ModuleConfig, CodegenContext, pre_lto_bitcode_filename};
+use rustc_codegen_ssa::back::write::{ModuleConfig, CodegenContext, FatLTOInput};
 use rustc_codegen_ssa::back::lto::{SerializedModule, LtoModuleCodegen, ThinShared, ThinModule};
 use rustc_codegen_ssa::traits::*;
 use back::write::{self, DiagnosticHandlers, with_llvm_pmb, save_temp_bitcode, to_llvm_opt_settings};
@@ -21,7 +21,6 @@ use rustc_codegen_ssa::{ModuleCodegen, ModuleKind};
 use libc;
 
 use std::ffi::{CStr, CString};
-use std::fs;
 use std::ptr;
 use std::slice;
 use std::sync::Arc;
@@ -133,7 +132,8 @@ fn prepare_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,
 /// Performs fat LTO by merging all modules into a single one and returning it
 /// for further optimization.
 pub(crate) fn run_fat(cgcx: &CodegenContext<LlvmCodegenBackend>,
-                      modules: Vec<ModuleCodegen<ModuleLlvm>>,
+                      modules: Vec<FatLTOInput<LlvmCodegenBackend>>,
+                      cached_modules: Vec<(SerializedModule<ModuleBuffer>, WorkProduct)>,
                       timeline: &mut Timeline)
     -> Result<LtoModuleCodegen<LlvmCodegenBackend>, FatalError>
 {
@@ -142,7 +142,15 @@ pub(crate) fn run_fat(cgcx: &CodegenContext<LlvmCodegenBackend>,
     let symbol_white_list = symbol_white_list.iter()
                                              .map(|c| c.as_ptr())
                                              .collect::<Vec<_>>();
-    fat_lto(cgcx, &diag_handler, modules, upstream_modules, &symbol_white_list, timeline)
+    fat_lto(
+        cgcx,
+        &diag_handler,
+        modules,
+        cached_modules,
+        upstream_modules,
+        &symbol_white_list,
+        timeline,
+    )
 }
 
 /// Performs thin LTO by performing necessary global analysis and returning two
@@ -173,33 +181,17 @@ pub(crate) fn run_thin(cgcx: &CodegenContext<LlvmCodegenBackend>,
 }
 
 pub(crate) fn prepare_thin(
-    cgcx: &CodegenContext<LlvmCodegenBackend>,
     module: ModuleCodegen<ModuleLlvm>
 ) -> (String, ThinBuffer) {
     let name = module.name.clone();
     let buffer = ThinBuffer::new(module.module_llvm.llmod());
-
-    // We emit the module after having serialized it into a ThinBuffer
-    // because only then it will contain the ThinLTO module summary.
-    if let Some(ref incr_comp_session_dir) = cgcx.incr_comp_session_dir {
-        if cgcx.config(module.kind).emit_pre_thin_lto_bc {
-            let path = incr_comp_session_dir
-                .join(pre_lto_bitcode_filename(&name));
-
-            fs::write(&path, buffer.data()).unwrap_or_else(|e| {
-                panic!("Error writing pre-lto-bitcode file `{}`: {}",
-                       path.display(),
-                       e);
-            });
-        }
-    }
-
     (name, buffer)
 }
 
 fn fat_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,
            diag_handler: &Handler,
-           mut modules: Vec<ModuleCodegen<ModuleLlvm>>,
+           mut modules: Vec<FatLTOInput<LlvmCodegenBackend>>,
+           cached_modules: Vec<(SerializedModule<ModuleBuffer>, WorkProduct)>,
            mut serialized_modules: Vec<(SerializedModule<ModuleBuffer>, CString)>,
            symbol_white_list: &[*const libc::c_char],
            timeline: &mut Timeline)
@@ -216,8 +208,14 @@ fn fat_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,
     // file copy operations in the backend work correctly. The only other kind
     // of module here should be an allocator one, and if your crate is smaller
     // than the allocator module then the size doesn't really matter anyway.
-    let (_, costliest_module) = modules.iter()
+    let costliest_module = modules.iter()
         .enumerate()
+        .filter_map(|(i, module)| {
+            match module {
+                FatLTOInput::InMemory(m) => Some((i, m)),
+                FatLTOInput::Serialized { .. } => None,
+            }
+        })
         .filter(|&(_, module)| module.kind == ModuleKind::Regular)
         .map(|(i, module)| {
             let cost = unsafe {
@@ -225,9 +223,38 @@ fn fat_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,
             };
             (cost, i)
         })
-        .max()
-        .expect("must be codegen'ing at least one module");
-    let module = modules.remove(costliest_module);
+        .max();
+
+    // If we found a costliest module, we're good to go. Otherwise all our
+    // inputs were serialized which could happen in the case, for example, that
+    // all our inputs were incrementally reread from the cache and we're just
+    // re-executing the LTO passes. If that's the case deserialize the first
+    // module and create a linker with it.
+    let module: ModuleCodegen<ModuleLlvm> = match costliest_module {
+        Some((_cost, i)) => {
+            match modules.remove(i) {
+                FatLTOInput::InMemory(m) => m,
+                FatLTOInput::Serialized { .. } => unreachable!(),
+            }
+        }
+        None => {
+            let pos = modules.iter().position(|m| {
+                match m {
+                    FatLTOInput::InMemory(_) => false,
+                    FatLTOInput::Serialized { .. } => true,
+                }
+            }).expect("must have at least one serialized module");
+            let (name, buffer) = match modules.remove(pos) {
+                FatLTOInput::Serialized { name, buffer } => (name, buffer),
+                FatLTOInput::InMemory(_) => unreachable!(),
+            };
+            ModuleCodegen {
+                module_llvm: ModuleLlvm::parse(cgcx, &name, &buffer, diag_handler)?,
+                name,
+                kind: ModuleKind::Regular,
+            }
+        }
+    };
     let mut serialized_bitcode = Vec::new();
     {
         let (llcx, llmod) = {
@@ -247,10 +274,20 @@ fn fat_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,
         // way we know of to do that is to serialize them to a string and them parse
         // them later. Not great but hey, that's why it's "fat" LTO, right?
         serialized_modules.extend(modules.into_iter().map(|module| {
-            let buffer = ModuleBuffer::new(module.module_llvm.llmod());
-            let llmod_id = CString::new(&module.name[..]).unwrap();
-
-            (SerializedModule::Local(buffer), llmod_id)
+            match module {
+                FatLTOInput::InMemory(module) => {
+                    let buffer = ModuleBuffer::new(module.module_llvm.llmod());
+                    let llmod_id = CString::new(&module.name[..]).unwrap();
+                    (SerializedModule::Local(buffer), llmod_id)
+                }
+                FatLTOInput::Serialized { name, buffer } => {
+                    let llmod_id = CString::new(name).unwrap();
+                    (SerializedModule::Local(buffer), llmod_id)
+                }
+            }
+        }));
+        serialized_modules.extend(cached_modules.into_iter().map(|(buffer, wp)| {
+            (buffer, CString::new(wp.cgu_name.clone()).unwrap())
         }));
 
         // For all serialized bitcode files we parse them and link them in as we did
@@ -579,6 +616,16 @@ impl ModuleBuffer {
             llvm::LLVMRustModuleBufferCreate(m)
         })
     }
+
+    pub fn parse<'a>(
+        &self,
+        name: &str,
+        cx: &'a llvm::Context,
+        handler: &Handler,
+    ) -> Result<&'a llvm::Module, FatalError> {
+        let name = CString::new(name).unwrap();
+        parse_module(cx, &name, self.data(), handler)
+    }
 }
 
 impl ModuleBufferMethods for ModuleBuffer {
@@ -658,15 +705,12 @@ pub unsafe fn optimize_thin_module(
     // crates but for locally codegened modules we may be able to reuse
     // that LLVM Context and Module.
     let llcx = llvm::LLVMRustContextCreate(cgcx.fewer_names);
-    let llmod_raw = llvm::LLVMRustParseBitcodeForThinLTO(
+    let llmod_raw = parse_module(
         llcx,
-        thin_module.data().as_ptr(),
-        thin_module.data().len(),
-        thin_module.shared.module_names[thin_module.idx].as_ptr(),
-    ).ok_or_else(|| {
-        let msg = "failed to parse bitcode for thin LTO module";
-        write::llvm_err(&diag_handler, msg)
-    })? as *const _;
+        &thin_module.shared.module_names[thin_module.idx],
+        thin_module.data(),
+        &diag_handler,
+    )? as *const _;
     let module = ModuleCodegen {
         module_llvm: ModuleLlvm {
             llmod_raw,
@@ -823,3 +867,22 @@ fn module_name_to_str(c_str: &CStr) -> &str {
     c_str.to_str().unwrap_or_else(|e|
         bug!("Encountered non-utf8 LLVM module name `{}`: {}", c_str.to_string_lossy(), e))
 }
+
+fn parse_module<'a>(
+    cx: &'a llvm::Context,
+    name: &CStr,
+    data: &[u8],
+    diag_handler: &Handler,
+) -> Result<&'a llvm::Module, FatalError> {
+    unsafe {
+        llvm::LLVMRustParseBitcodeForLTO(
+            cx,
+            data.as_ptr(),
+            data.len(),
+            name.as_ptr(),
+        ).ok_or_else(|| {
+            let msg = "failed to parse bitcode for LTO module";
+            write::llvm_err(&diag_handler, msg)
+        })
+    }
+}
diff --git a/src/librustc_codegen_llvm/lib.rs b/src/librustc_codegen_llvm/lib.rs
index ad8db25ee95a0..b605badc153f0 100644
--- a/src/librustc_codegen_llvm/lib.rs
+++ b/src/librustc_codegen_llvm/lib.rs
@@ -54,7 +54,7 @@ extern crate tempfile;
 extern crate memmap;
 
 use rustc_codegen_ssa::traits::*;
-use rustc_codegen_ssa::back::write::{CodegenContext, ModuleConfig};
+use rustc_codegen_ssa::back::write::{CodegenContext, ModuleConfig, FatLTOInput};
 use rustc_codegen_ssa::back::lto::{SerializedModule, LtoModuleCodegen, ThinModule};
 use rustc_codegen_ssa::CompiledModule;
 use errors::{FatalError, Handler};
@@ -165,10 +165,11 @@ impl WriteBackendMethods for LlvmCodegenBackend {
     }
     fn run_fat_lto(
         cgcx: &CodegenContext<Self>,
-        modules: Vec<ModuleCodegen<Self::Module>>,
+        modules: Vec<FatLTOInput<Self>>,
+        cached_modules: Vec<(SerializedModule<Self::ModuleBuffer>, WorkProduct)>,
         timeline: &mut Timeline
     ) -> Result<LtoModuleCodegen<Self>, FatalError> {
-        back::lto::run_fat(cgcx, modules, timeline)
+        back::lto::run_fat(cgcx, modules, cached_modules, timeline)
     }
     fn run_thin_lto(
         cgcx: &CodegenContext<Self>,
@@ -204,10 +205,14 @@ impl WriteBackendMethods for LlvmCodegenBackend {
         back::write::codegen(cgcx, diag_handler, module, config, timeline)
     }
     fn prepare_thin(
-        cgcx: &CodegenContext<Self>,
         module: ModuleCodegen<Self::Module>
     ) -> (String, Self::ThinBuffer) {
-        back::lto::prepare_thin(cgcx, module)
+        back::lto::prepare_thin(module)
+    }
+    fn serialize_module(
+        module: ModuleCodegen<Self::Module>
+    ) -> (String, Self::ModuleBuffer) {
+        (module.name, back::lto::ModuleBuffer::new(module.module_llvm.llmod()))
     }
     fn run_lto_pass_manager(
         cgcx: &CodegenContext<Self>,
@@ -375,6 +380,31 @@ impl ModuleLlvm {
         }
     }
 
+    fn parse(
+        cgcx: &CodegenContext<LlvmCodegenBackend>,
+        name: &str,
+        buffer: &back::lto::ModuleBuffer,
+        handler: &Handler,
+    ) -> Result<Self, FatalError> {
+        unsafe {
+            let llcx = llvm::LLVMRustContextCreate(cgcx.fewer_names);
+            let llmod_raw = buffer.parse(name, llcx, handler)?;
+            let tm = match (cgcx.tm_factory.0)() {
+                Ok(m) => m,
+                Err(e) => {
+                    handler.struct_err(&e).emit();
+                    return Err(FatalError)
+                }
+            };
+
+            Ok(ModuleLlvm {
+                llmod_raw,
+                llcx,
+                tm,
+            })
+        }
+    }
+
     fn llmod(&self) -> &llvm::Module {
         unsafe {
             &*self.llmod_raw
diff --git a/src/librustc_codegen_llvm/llvm/ffi.rs b/src/librustc_codegen_llvm/llvm/ffi.rs
index 3232f4e8f51ac..52292f67b331d 100644
--- a/src/librustc_codegen_llvm/llvm/ffi.rs
+++ b/src/librustc_codegen_llvm/llvm/ffi.rs
@@ -1804,7 +1804,7 @@ extern "C" {
         CallbackPayload: *mut c_void,
     );
     pub fn LLVMRustFreeThinLTOData(Data: &'static mut ThinLTOData);
-    pub fn LLVMRustParseBitcodeForThinLTO(
+    pub fn LLVMRustParseBitcodeForLTO(
         Context: &Context,
         Data: *const u8,
         len: usize,
diff --git a/src/librustc_codegen_ssa/back/write.rs b/src/librustc_codegen_ssa/back/write.rs
index 2922d326c3b35..20842553c2666 100644
--- a/src/librustc_codegen_ssa/back/write.rs
+++ b/src/librustc_codegen_ssa/back/write.rs
@@ -41,7 +41,7 @@ use std::sync::mpsc::{channel, Sender, Receiver};
 use std::time::Instant;
 use std::thread;
 
-const PRE_THIN_LTO_BC_EXT: &str = "pre-thin-lto.bc";
+const PRE_LTO_BC_EXT: &str = "pre-lto.bc";
 
 /// Module-specific configuration for `optimize_and_codegen`.
 pub struct ModuleConfig {
@@ -58,7 +58,7 @@ pub struct ModuleConfig {
     pub pgo_use: String,
 
     // Flags indicating which outputs to produce.
-    pub emit_pre_thin_lto_bc: bool,
+    pub emit_pre_lto_bc: bool,
     pub emit_no_opt_bc: bool,
     pub emit_bc: bool,
     pub emit_bc_compressed: bool,
@@ -96,7 +96,7 @@ impl ModuleConfig {
             pgo_use: String::new(),
 
             emit_no_opt_bc: false,
-            emit_pre_thin_lto_bc: false,
+            emit_pre_lto_bc: false,
             emit_bc: false,
             emit_bc_compressed: false,
             emit_lto_bc: false,
@@ -258,7 +258,7 @@ impl<B: WriteBackendMethods> CodegenContext<B> {
 
 fn generate_lto_work<B: ExtraBackendMethods>(
     cgcx: &CodegenContext<B>,
-    needs_fat_lto: Vec<ModuleCodegen<B::Module>>,
+    needs_fat_lto: Vec<FatLTOInput<B>>,
     needs_thin_lto: Vec<(String, B::ThinBuffer)>,
     import_only_modules: Vec<(SerializedModule<B::ModuleBuffer>, WorkProduct)>
 ) -> Vec<(WorkItem<B>, u64)> {
@@ -270,9 +270,13 @@ fn generate_lto_work<B: ExtraBackendMethods>(
 
     let (lto_modules, copy_jobs) = if !needs_fat_lto.is_empty() {
         assert!(needs_thin_lto.is_empty());
-        assert!(import_only_modules.is_empty());
-        let lto_module = B::run_fat_lto(cgcx, needs_fat_lto, &mut timeline)
-            .unwrap_or_else(|e| e.raise());
+        let lto_module = B::run_fat_lto(
+            cgcx,
+            needs_fat_lto,
+            import_only_modules,
+            &mut timeline,
+        )
+        .unwrap_or_else(|e| e.raise());
         (vec![lto_module], vec![])
     } else {
         assert!(needs_fat_lto.is_empty());
@@ -302,14 +306,14 @@ fn need_crate_bitcode_for_rlib(sess: &Session) -> bool {
     sess.opts.output_types.contains_key(&OutputType::Exe)
 }
 
-fn need_pre_thin_lto_bitcode_for_incr_comp(sess: &Session) -> bool {
+fn need_pre_lto_bitcode_for_incr_comp(sess: &Session) -> bool {
     if sess.opts.incremental.is_none() {
         return false
     }
 
     match sess.lto() {
-        Lto::Fat |
         Lto::No => false,
+        Lto::Fat |
         Lto::Thin |
         Lto::ThinLocal => true,
     }
@@ -375,7 +379,7 @@ pub fn start_async_codegen<B: ExtraBackendMethods>(
     // Save all versions of the bytecode if we're saving our temporaries.
     if sess.opts.cg.save_temps {
         modules_config.emit_no_opt_bc = true;
-        modules_config.emit_pre_thin_lto_bc = true;
+        modules_config.emit_pre_lto_bc = true;
         modules_config.emit_bc = true;
         modules_config.emit_lto_bc = true;
         metadata_config.emit_bc = true;
@@ -390,8 +394,8 @@ pub fn start_async_codegen<B: ExtraBackendMethods>(
         allocator_config.emit_bc_compressed = true;
     }
 
-    modules_config.emit_pre_thin_lto_bc =
-        need_pre_thin_lto_bitcode_for_incr_comp(sess);
+    modules_config.emit_pre_lto_bc =
+        need_pre_lto_bitcode_for_incr_comp(sess);
 
     modules_config.no_integrated_as = tcx.sess.opts.cg.no_integrated_as ||
         tcx.sess.target.target.options.no_integrated_as;
@@ -686,10 +690,18 @@ impl<B: WriteBackendMethods> WorkItem<B> {
 
 enum WorkItemResult<B: WriteBackendMethods> {
     Compiled(CompiledModule),
-    NeedsFatLTO(ModuleCodegen<B::Module>),
+    NeedsFatLTO(FatLTOInput<B>),
     NeedsThinLTO(String, B::ThinBuffer),
 }
 
+pub enum FatLTOInput<B: WriteBackendMethods> {
+    Serialized {
+        name: String,
+        buffer: B::ModuleBuffer,
+    },
+    InMemory(ModuleCodegen<B::Module>),
+}
+
 fn execute_work_item<B: ExtraBackendMethods>(
     cgcx: &CodegenContext<B>,
     work_item: WorkItem<B>,
@@ -771,6 +783,15 @@ fn execute_optimize_work_item<B: ExtraBackendMethods>(
         }
     };
 
+    // If we're doing some form of incremental LTO then we need to be sure to
+    // save our module to disk first.
+    let bitcode = if cgcx.config(module.kind).emit_pre_lto_bc {
+        let filename = pre_lto_bitcode_filename(&module.name);
+        cgcx.incr_comp_session_dir.as_ref().map(|path| path.join(&filename))
+    } else {
+        None
+    };
+
     Ok(match lto_type {
         ComputedLtoType::No => {
             let module = unsafe {
@@ -779,10 +800,30 @@ fn execute_optimize_work_item<B: ExtraBackendMethods>(
             WorkItemResult::Compiled(module)
         }
         ComputedLtoType::Thin => {
-            let (name, thin_buffer) = B::prepare_thin(cgcx, module);
+            let (name, thin_buffer) = B::prepare_thin(module);
+            if let Some(path) = bitcode {
+                fs::write(&path, thin_buffer.data()).unwrap_or_else(|e| {
+                    panic!("Error writing pre-lto-bitcode file `{}`: {}",
+                           path.display(),
+                           e);
+                });
+            }
             WorkItemResult::NeedsThinLTO(name, thin_buffer)
         }
-        ComputedLtoType::Fat => WorkItemResult::NeedsFatLTO(module),
+        ComputedLtoType::Fat => {
+            match bitcode {
+                Some(path) => {
+                    let (name, buffer) = B::serialize_module(module);
+                    fs::write(&path, buffer.data()).unwrap_or_else(|e| {
+                        panic!("Error writing pre-lto-bitcode file `{}`: {}",
+                               path.display(),
+                               e);
+                    });
+                    WorkItemResult::NeedsFatLTO(FatLTOInput::Serialized { name, buffer })
+                }
+                None => WorkItemResult::NeedsFatLTO(FatLTOInput::InMemory(module)),
+            }
+        }
     })
 }
 
@@ -866,7 +907,7 @@ fn execute_lto_work_item<B: ExtraBackendMethods>(
 pub enum Message<B: WriteBackendMethods> {
     Token(io::Result<Acquired>),
     NeedsFatLTO {
-        result: ModuleCodegen<B::Module>,
+        result: FatLTOInput<B>,
         worker_id: usize,
     },
     NeedsThinLTO {
@@ -1877,7 +1918,7 @@ pub fn submit_pre_lto_module_to_llvm<B: ExtraBackendMethods>(
 }
 
 pub fn pre_lto_bitcode_filename(module_name: &str) -> String {
-    format!("{}.{}", module_name, PRE_THIN_LTO_BC_EXT)
+    format!("{}.{}", module_name, PRE_LTO_BC_EXT)
 }
 
 fn msvc_imps_needed(tcx: TyCtxt) -> bool {
diff --git a/src/librustc_codegen_ssa/traits/write.rs b/src/librustc_codegen_ssa/traits/write.rs
index e8ef815b32acb..d8fb7c608c8af 100644
--- a/src/librustc_codegen_ssa/traits/write.rs
+++ b/src/librustc_codegen_ssa/traits/write.rs
@@ -1,5 +1,5 @@
 use crate::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule};
-use crate::back::write::{CodegenContext, ModuleConfig};
+use crate::back::write::{CodegenContext, ModuleConfig, FatLTOInput};
 use crate::{CompiledModule, ModuleCodegen};
 
 use rustc::dep_graph::WorkProduct;
@@ -18,7 +18,8 @@ pub trait WriteBackendMethods: 'static + Sized + Clone {
     /// for further optimization.
     fn run_fat_lto(
         cgcx: &CodegenContext<Self>,
-        modules: Vec<ModuleCodegen<Self::Module>>,
+        modules: Vec<FatLTOInput<Self>>,
+        cached_modules: Vec<(SerializedModule<Self::ModuleBuffer>, WorkProduct)>,
         timeline: &mut Timeline,
     ) -> Result<LtoModuleCodegen<Self>, FatalError>;
     /// Performs thin LTO by performing necessary global analysis and returning two
@@ -51,9 +52,11 @@ pub trait WriteBackendMethods: 'static + Sized + Clone {
         timeline: &mut Timeline,
     ) -> Result<CompiledModule, FatalError>;
     fn prepare_thin(
-        cgcx: &CodegenContext<Self>,
         module: ModuleCodegen<Self::Module>
     ) -> (String, Self::ThinBuffer);
+    fn serialize_module(
+        module: ModuleCodegen<Self::Module>
+    ) -> (String, Self::ModuleBuffer);
     fn run_lto_pass_manager(
         cgcx: &CodegenContext<Self>,
         llmod: &ModuleCodegen<Self::Module>,
diff --git a/src/librustc_lint/Cargo.toml b/src/librustc_lint/Cargo.toml
index 82f7118df2d0b..fd2b635faefb4 100644
--- a/src/librustc_lint/Cargo.toml
+++ b/src/librustc_lint/Cargo.toml
@@ -8,7 +8,6 @@ edition = "2018"
 name = "rustc_lint"
 path = "lib.rs"
 crate-type = ["dylib"]
-test = false
 
 [dependencies]
 log = "0.4"
diff --git a/src/librustc_lint/nonstandard_style.rs b/src/librustc_lint/nonstandard_style.rs
index 2dbafc7ede2a2..c2dd9a3d1b84f 100644
--- a/src/librustc_lint/nonstandard_style.rs
+++ b/src/librustc_lint/nonstandard_style.rs
@@ -38,66 +38,87 @@ declare_lint! {
     "types, variants, traits and type parameters should have camel case names"
 }
 
-#[derive(Copy, Clone)]
-pub struct NonCamelCaseTypes;
+fn char_has_case(c: char) -> bool {
+    c.is_lowercase() || c.is_uppercase()
+}
 
-impl NonCamelCaseTypes {
-    fn check_case(&self, cx: &EarlyContext<'_>, sort: &str, ident: &Ident) {
-        fn char_has_case(c: char) -> bool {
-            c.is_lowercase() || c.is_uppercase()
-        }
+fn is_camel_case(name: &str) -> bool {
+    let name = name.trim_matches('_');
+    if name.is_empty() {
+        return true;
+    }
 
-        fn is_camel_case(name: &str) -> bool {
-            let name = name.trim_matches('_');
-            if name.is_empty() {
-                return true;
+    // start with a non-lowercase letter rather than non-uppercase
+    // ones (some scripts don't have a concept of upper/lowercase)
+    !name.chars().next().unwrap().is_lowercase()
+        && !name.contains("__")
+        && !name.chars().collect::<Vec<_>>().windows(2).any(|pair| {
+            // contains a capitalisable character followed by, or preceded by, an underscore
+            char_has_case(pair[0]) && pair[1] == '_' || char_has_case(pair[1]) && pair[0] == '_'
+        })
+}
+
+fn to_camel_case(s: &str) -> String {
+    s.trim_matches('_')
+        .split('_')
+        .filter(|component| !component.is_empty())
+        .map(|component| {
+            let mut camel_cased_component = String::new();
+
+            let mut new_word = true;
+            let mut prev_is_lower_case = true;
+
+            for c in component.chars() {
+                // Preserve the case if an uppercase letter follows a lowercase letter, so that
+                // `camelCase` is converted to `CamelCase`.
+                if prev_is_lower_case && c.is_uppercase() {
+                    new_word = true;
+                }
+
+                if new_word {
+                    camel_cased_component.push_str(&c.to_uppercase().to_string());
+                } else {
+                    camel_cased_component.push_str(&c.to_lowercase().to_string());
+                }
+
+                prev_is_lower_case = c.is_lowercase();
+                new_word = false;
             }
 
-            // start with a non-lowercase letter rather than non-uppercase
-            // ones (some scripts don't have a concept of upper/lowercase)
-            !name.is_empty() && !name.chars().next().unwrap().is_lowercase() &&
-                !name.contains("__") && !name.chars().collect::<Vec<_>>().windows(2).any(|pair| {
-                    // contains a capitalisable character followed by, or preceded by, an underscore
-                    char_has_case(pair[0]) && pair[1] == '_' ||
-                    char_has_case(pair[1]) && pair[0] == '_'
-                })
-        }
+            camel_cased_component
+        })
+        .fold(
+            (String::new(), None),
+            |(acc, prev): (String, Option<String>), next| {
+                // separate two components with an underscore if their boundary cannot
+                // be distinguished using a uppercase/lowercase case distinction
+                let join = if let Some(prev) = prev {
+                    let l = prev.chars().last().unwrap();
+                    let f = next.chars().next().unwrap();
+                    !char_has_case(l) && !char_has_case(f)
+                } else {
+                    false
+                };
+                (acc + if join { "_" } else { "" } + &next, Some(next))
+            },
+        )
+        .0
+}
 
-        fn to_camel_case(s: &str) -> String {
-            s.trim_matches('_')
-                .split('_')
-                .map(|word| {
-                    word.chars().enumerate().map(|(i, c)| if i == 0 {
-                        c.to_uppercase().collect::<String>()
-                    } else {
-                        c.to_lowercase().collect()
-                    })
-                    .collect::<String>()
-                })
-                .filter(|x| !x.is_empty())
-                .fold((String::new(), None), |(acc, prev): (String, Option<String>), next| {
-                    // separate two components with an underscore if their boundary cannot
-                    // be distinguished using a uppercase/lowercase case distinction
-                    let join = if let Some(prev) = prev {
-                                    let l = prev.chars().last().unwrap();
-                                    let f = next.chars().next().unwrap();
-                                    !char_has_case(l) && !char_has_case(f)
-                                } else { false };
-                    (acc + if join { "_" } else { "" } + &next, Some(next))
-                }).0
-        }
+#[derive(Copy, Clone)]
+pub struct NonCamelCaseTypes;
 
+impl NonCamelCaseTypes {
+    fn check_case(&self, cx: &EarlyContext<'_>, sort: &str, ident: &Ident) {
         let name = &ident.name.as_str();
 
         if !is_camel_case(name) {
-            let c = to_camel_case(name);
-
-            let msg = format!("{} `{}` should have a camel case name", sort, name);
+            let msg = format!("{} `{}` should have an upper camel case name", sort, name);
             cx.struct_span_lint(NON_CAMEL_CASE_TYPES, ident.span, &msg)
                 .span_suggestion(
                     ident.span,
-                    "convert the identifier to camel case",
-                    c,
+                    "convert the identifier to upper camel case",
+                    to_camel_case(name),
                     Applicability::MaybeIncorrect,
                 )
                 .emit();
@@ -119,11 +140,7 @@ impl EarlyLintPass for NonCamelCaseTypes {
     fn check_item(&mut self, cx: &EarlyContext<'_>, it: &ast::Item) {
         let has_repr_c = it.attrs
             .iter()
-            .any(|attr| {
-                attr::find_repr_attrs(&cx.sess.parse_sess, attr)
-                    .iter()
-                    .any(|r| r == &attr::ReprC)
-            });
+            .any(|attr| attr::find_repr_attrs(&cx.sess.parse_sess, attr).contains(&attr::ReprC));
 
         if has_repr_c {
             return;
@@ -439,3 +456,28 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonUpperCaseGlobals {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::{is_camel_case, to_camel_case};
+
+    #[test]
+    fn camel_case() {
+        assert!(!is_camel_case("userData"));
+        assert_eq!(to_camel_case("userData"), "UserData");
+
+        assert!(is_camel_case("X86_64"));
+
+        assert!(!is_camel_case("X86__64"));
+        assert_eq!(to_camel_case("X86__64"), "X86_64");
+
+        assert!(!is_camel_case("Abc_123"));
+        assert_eq!(to_camel_case("Abc_123"), "Abc123");
+
+        assert!(!is_camel_case("A1_b2_c3"));
+        assert_eq!(to_camel_case("A1_b2_c3"), "A1B2C3");
+
+        assert!(!is_camel_case("ONE_TWO_THREE"));
+        assert_eq!(to_camel_case("ONE_TWO_THREE"), "OneTwoThree");
+    }
+}
diff --git a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/mod.rs b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/mod.rs
index f741af0b228b5..081c458bfc17a 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/mod.rs
@@ -244,7 +244,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         if let (Some(f), Some(o)) = (self.to_error_region(fr), self.to_error_region(outlived_fr)) {
             let tables = infcx.tcx.typeck_tables_of(mir_def_id);
             let nice = NiceRegionError::new_from_span(infcx, span, o, f, Some(tables));
-            if let Some(_error_reported) = nice.try_report_from_nll() {
+            if let Some(diag) = nice.try_report_from_nll() {
+                diag.buffer(errors_buffer);
                 return;
             }
         }
diff --git a/src/librustc_mir/borrow_check/nll/region_infer/mod.rs b/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
index 6de05777fe888..cbeb5dc206ee6 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
@@ -15,7 +15,7 @@ use rustc::mir::{
     ConstraintCategory, Local, Location, Mir,
 };
 use rustc::ty::{self, RegionVid, Ty, TyCtxt, TypeFoldable};
-use rustc::util::common;
+use rustc::util::common::{self, ErrorReported};
 use rustc_data_structures::bit_set::BitSet;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::graph::scc::Sccs;
@@ -763,20 +763,26 @@ impl<'tcx> RegionInferenceContext<'tcx> {
 
             debug!("try_promote_type_test: ur={:?}", ur);
 
-            let non_local_ub = self.universal_region_relations.non_local_upper_bound(ur);
+            let non_local_ub = self.universal_region_relations.non_local_upper_bounds(&ur);
             debug!("try_promote_type_test: non_local_ub={:?}", non_local_ub);
 
-            assert!(self.universal_regions.is_universal_region(non_local_ub));
-            assert!(!self.universal_regions.is_local_free_region(non_local_ub));
-
-            let requirement = ClosureOutlivesRequirement {
-                subject,
-                outlived_free_region: non_local_ub,
-                blame_span: locations.span(mir),
-                category: ConstraintCategory::Boring,
-            };
-            debug!("try_promote_type_test: pushing {:#?}", requirement);
-            propagated_outlives_requirements.push(requirement);
+            // This is slightly too conservative. To show T: '1, given `'2: '1`
+            // and `'3: '1` we only need to prove that T: '2 *or* T: '3, but to
+            // avoid potential non-determinism we approximate this by requiring
+            // T: '1 and T: '2.
+            for &upper_bound in non_local_ub {
+                debug_assert!(self.universal_regions.is_universal_region(upper_bound));
+                debug_assert!(!self.universal_regions.is_local_free_region(upper_bound));
+
+                let requirement = ClosureOutlivesRequirement {
+                    subject,
+                    outlived_free_region: upper_bound,
+                    blame_span: locations.span(mir),
+                    category: ConstraintCategory::Boring,
+                };
+                debug!("try_promote_type_test: pushing {:#?}", requirement);
+                propagated_outlives_requirements.push(requirement);
+            }
         }
         true
     }
@@ -1157,63 +1163,109 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                 .is_none()
         );
 
+        // Only check all of the relations for the main representative of each
+        // SCC, otherwise just check that we outlive said representative. This
+        // reduces the number of redundant relations propagated out of
+        // closures.
+        // Note that the representative will be a universal region if there is
+        // one in this SCC, so we will always check the representative here.
+        let representative = self.scc_representatives[longer_fr_scc];
+        if representative != longer_fr {
+            self.check_universal_region_relation(
+                longer_fr,
+                representative,
+                infcx,
+                mir,
+                mir_def_id,
+                propagated_outlives_requirements,
+                errors_buffer,
+            );
+            return;
+        }
+
         // Find every region `o` such that `fr: o`
         // (because `fr` includes `end(o)`).
         for shorter_fr in self.scc_values.universal_regions_outlived_by(longer_fr_scc) {
-            // If it is known that `fr: o`, carry on.
-            if self.universal_region_relations
-                .outlives(longer_fr, shorter_fr)
-            {
-                continue;
+            if let Some(ErrorReported) = self.check_universal_region_relation(
+                longer_fr,
+                shorter_fr,
+                infcx,
+                mir,
+                mir_def_id,
+                propagated_outlives_requirements,
+                errors_buffer,
+            ) {
+                // continuing to iterate just reports more errors than necessary
+                return;
             }
+        }
+    }
 
-            debug!(
-                "check_universal_region: fr={:?} does not outlive shorter_fr={:?}",
-                longer_fr, shorter_fr,
-            );
+    fn check_universal_region_relation(
+        &self,
+        longer_fr: RegionVid,
+        shorter_fr: RegionVid,
+        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        mir: &Mir<'tcx>,
+        mir_def_id: DefId,
+        propagated_outlives_requirements: &mut Option<&mut Vec<ClosureOutlivesRequirement<'gcx>>>,
+        errors_buffer: &mut Vec<Diagnostic>,
+    ) -> Option<ErrorReported> {
+        // If it is known that `fr: o`, carry on.
+        if self.universal_region_relations
+            .outlives(longer_fr, shorter_fr)
+        {
+            return None;
+        }
 
-            let blame_span_category = self.find_outlives_blame_span(mir, longer_fr, shorter_fr);
-
-            if let Some(propagated_outlives_requirements) = propagated_outlives_requirements {
-                // Shrink `fr` until we find a non-local region (if we do).
-                // We'll call that `fr-` -- it's ever so slightly smaller than `fr`.
-                if let Some(fr_minus) = self.universal_region_relations
-                    .non_local_lower_bound(longer_fr)
-                {
-                    debug!("check_universal_region: fr_minus={:?}", fr_minus);
-
-                    // Grow `shorter_fr` until we find a non-local
-                    // region. (We always will.)  We'll call that
-                    // `shorter_fr+` -- it's ever so slightly larger than
-                    // `fr`.
-                    let shorter_fr_plus = self.universal_region_relations
-                        .non_local_upper_bound(shorter_fr);
-                    debug!(
-                        "check_universal_region: shorter_fr_plus={:?}",
-                        shorter_fr_plus
-                    );
+        debug!(
+            "check_universal_region_relation: fr={:?} does not outlive shorter_fr={:?}",
+            longer_fr, shorter_fr,
+        );
 
+        if let Some(propagated_outlives_requirements) = propagated_outlives_requirements {
+            // Shrink `longer_fr` until we find a non-local region (if we do).
+            // We'll call it `fr-` -- it's ever so slightly smaller than
+            // `longer_fr`.
+
+            if let Some(fr_minus) = self
+                .universal_region_relations
+                .non_local_lower_bound(longer_fr)
+            {
+                debug!("check_universal_region: fr_minus={:?}", fr_minus);
+
+                let blame_span_category = self.find_outlives_blame_span(mir, longer_fr, shorter_fr);
+
+                // Grow `shorter_fr` until we find some non-local regions. (We
+                // always will.)  We'll call them `shorter_fr+` -- they're ever
+                // so slightly larger than `shorter_fr`.
+                let shorter_fr_plus = self.universal_region_relations
+                    .non_local_upper_bounds(&shorter_fr);
+                debug!(
+                    "check_universal_region: shorter_fr_plus={:?}",
+                    shorter_fr_plus
+                );
+                for &&fr in &shorter_fr_plus {
                     // Push the constraint `fr-: shorter_fr+`
                     propagated_outlives_requirements.push(ClosureOutlivesRequirement {
                         subject: ClosureOutlivesSubject::Region(fr_minus),
-                        outlived_free_region: shorter_fr_plus,
+                        outlived_free_region: fr,
                         blame_span: blame_span_category.1,
                         category: blame_span_category.0,
                     });
-                    continue;
                 }
+                return None;
             }
-
-            // If we are not in a context where we can propagate
-            // errors, or we could not shrink `fr` to something
-            // smaller, then just report an error.
-            //
-            // Note: in this case, we use the unapproximated regions
-            // to report the error. This gives better error messages
-            // in some cases.
-            self.report_error(mir, infcx, mir_def_id, longer_fr, shorter_fr, errors_buffer);
-            return; // continuing to iterate just reports more errors than necessary
         }
+
+        // If we are not in a context where we can't propagate errors, or we
+        // could not shrink `fr` to something smaller, then just report an
+        // error.
+        //
+        // Note: in this case, we use the unapproximated regions to report the
+        // error. This gives better error messages in some cases.
+        self.report_error(mir, infcx, mir_def_id, longer_fr, shorter_fr, errors_buffer);
+        Some(ErrorReported)
     }
 
     fn check_bound_universal_region<'gcx>(
diff --git a/src/librustc_mir/borrow_check/nll/type_check/free_region_relations.rs b/src/librustc_mir/borrow_check/nll/type_check/free_region_relations.rs
index 7ddfd55dbbb94..3b663ef6dad61 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/free_region_relations.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/free_region_relations.rs
@@ -105,44 +105,89 @@ impl UniversalRegionRelations<'tcx> {
 
     /// Finds an "upper bound" for `fr` that is not local. In other
     /// words, returns the smallest (*) known region `fr1` that (a)
-    /// outlives `fr` and (b) is not local. This cannot fail, because
-    /// we will always find `'static` at worst.
+    /// outlives `fr` and (b) is not local.
     ///
-    /// (*) If there are multiple competing choices, we pick the "postdominating"
-    /// one. See `TransitiveRelation::postdom_upper_bound` for details.
-    crate fn non_local_upper_bound(&self, fr: RegionVid) -> RegionVid {
+    /// (*) If there are multiple competing choices, we return all of them.
+    crate fn non_local_upper_bounds(&'a self, fr: &'a RegionVid) -> Vec<&'a RegionVid> {
         debug!("non_local_upper_bound(fr={:?})", fr);
-        self.non_local_bound(&self.inverse_outlives, fr)
+        let res = self.non_local_bounds(&self.inverse_outlives, fr);
+        assert!(!res.is_empty(), "can't find an upper bound!?");
+        res
+    }
+
+    /// Returns the "postdominating" bound of the set of
+    /// `non_local_upper_bounds` for the given region.
+    crate fn non_local_upper_bound(&self, fr: RegionVid) -> RegionVid {
+        let upper_bounds = self.non_local_upper_bounds(&fr);
+
+        // In case we find more than one, reduce to one for
+        // convenience.  This is to prevent us from generating more
+        // complex constraints, but it will cause spurious errors.
+        let post_dom = self
+            .inverse_outlives
+            .mutual_immediate_postdominator(upper_bounds);
+
+        debug!("non_local_bound: post_dom={:?}", post_dom);
+
+        post_dom
+            .and_then(|&post_dom| {
+                // If the mutual immediate postdom is not local, then
+                // there is no non-local result we can return.
+                if !self.universal_regions.is_local_free_region(post_dom) {
+                    Some(post_dom)
+                } else {
+                    None
+                }
+            })
             .unwrap_or(self.universal_regions.fr_static)
     }
 
+
     /// Finds a "lower bound" for `fr` that is not local. In other
     /// words, returns the largest (*) known region `fr1` that (a) is
-    /// outlived by `fr` and (b) is not local. This cannot fail,
-    /// because we will always find `'static` at worst.
+    /// outlived by `fr` and (b) is not local.
     ///
     /// (*) If there are multiple competing choices, we pick the "postdominating"
     /// one. See `TransitiveRelation::postdom_upper_bound` for details.
     crate fn non_local_lower_bound(&self, fr: RegionVid) -> Option<RegionVid> {
         debug!("non_local_lower_bound(fr={:?})", fr);
-        self.non_local_bound(&self.outlives, fr)
+        let lower_bounds = self.non_local_bounds(&self.outlives, &fr);
+
+        // In case we find more than one, reduce to one for
+        // convenience.  This is to prevent us from generating more
+        // complex constraints, but it will cause spurious errors.
+        let post_dom = self
+            .outlives
+            .mutual_immediate_postdominator(lower_bounds);
+
+        debug!("non_local_bound: post_dom={:?}", post_dom);
+
+        post_dom
+            .and_then(|&post_dom| {
+                // If the mutual immediate postdom is not local, then
+                // there is no non-local result we can return.
+                if !self.universal_regions.is_local_free_region(post_dom) {
+                    Some(post_dom)
+                } else {
+                    None
+                }
+            })
     }
 
-    /// Helper for `non_local_upper_bound` and
-    /// `non_local_lower_bound`. Repeatedly invokes `postdom_parent`
-    /// until we find something that is not local. Returns `None` if we
-    /// never do so.
-    fn non_local_bound(
+    /// Helper for `non_local_upper_bounds` and `non_local_lower_bounds`.
+    /// Repeatedly invokes `postdom_parent` until we find something that is not
+    /// local. Returns `None` if we never do so.
+    fn non_local_bounds<'a>(
         &self,
-        relation: &TransitiveRelation<RegionVid>,
-        fr0: RegionVid,
-    ) -> Option<RegionVid> {
+        relation: &'a TransitiveRelation<RegionVid>,
+        fr0: &'a RegionVid,
+    ) -> Vec<&'a RegionVid> {
         // This method assumes that `fr0` is one of the universally
         // quantified region variables.
-        assert!(self.universal_regions.is_universal_region(fr0));
+        assert!(self.universal_regions.is_universal_region(*fr0));
 
         let mut external_parents = vec![];
-        let mut queue = vec![&fr0];
+        let mut queue = vec![fr0];
 
         // Keep expanding `fr` into its parents until we reach
         // non-local regions.
@@ -157,24 +202,7 @@ impl UniversalRegionRelations<'tcx> {
 
         debug!("non_local_bound: external_parents={:?}", external_parents);
 
-        // In case we find more than one, reduce to one for
-        // convenience.  This is to prevent us from generating more
-        // complex constraints, but it will cause spurious errors.
-        let post_dom = relation
-            .mutual_immediate_postdominator(external_parents)
-            .cloned();
-
-        debug!("non_local_bound: post_dom={:?}", post_dom);
-
-        post_dom.and_then(|post_dom| {
-            // If the mutual immediate postdom is not local, then
-            // there is no non-local result we can return.
-            if !self.universal_regions.is_local_free_region(post_dom) {
-                Some(post_dom)
-            } else {
-                None
-            }
-        })
+        external_parents
     }
 
     /// Returns `true` if fr1 is known to outlive fr2.
diff --git a/src/librustc_mir/build/matches/mod.rs b/src/librustc_mir/build/matches/mod.rs
index cb71ff27ceb53..28d2a397f3ed6 100644
--- a/src/librustc_mir/build/matches/mod.rs
+++ b/src/librustc_mir/build/matches/mod.rs
@@ -7,7 +7,7 @@ use crate::build::scope::{CachedBlock, DropKind};
 use crate::build::ForGuard::{self, OutsideGuard, RefWithinGuard, ValWithinGuard};
 use crate::build::{BlockAnd, BlockAndExtension, Builder};
 use crate::build::{GuardFrame, GuardFrameLocal, LocalsForNode};
-use crate::hair::*;
+use crate::hair::{self, *};
 use rustc::mir::*;
 use rustc::ty::{self, CanonicalUserTypeAnnotation, Ty};
 use rustc::ty::layout::VariantIdx;
@@ -283,9 +283,11 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     },
                     ..
                 },
-                user_ty: pat_ascription_ty,
-                variance: _,
-                user_ty_span,
+                ascription: hair::pattern::Ascription {
+                    user_ty: pat_ascription_ty,
+                    variance: _,
+                    user_ty_span,
+                },
             } => {
                 let place =
                     self.storage_live_binding(block, var, irrefutable_pat.span, OutsideGuard);
@@ -560,9 +562,11 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             }
             PatternKind::AscribeUserType {
                 ref subpattern,
-                ref user_ty,
-                user_ty_span,
-                variance: _,
+                ascription: hair::pattern::Ascription {
+                    ref user_ty,
+                    user_ty_span,
+                    variance: _,
+                },
             } => {
                 // This corresponds to something like
                 //
diff --git a/src/librustc_mir/build/matches/simplify.rs b/src/librustc_mir/build/matches/simplify.rs
index 6be9ccb27036e..b8e38e40b6347 100644
--- a/src/librustc_mir/build/matches/simplify.rs
+++ b/src/librustc_mir/build/matches/simplify.rs
@@ -14,7 +14,7 @@
 
 use crate::build::Builder;
 use crate::build::matches::{Ascription, Binding, MatchPair, Candidate};
-use crate::hair::*;
+use crate::hair::{self, *};
 use rustc::ty;
 use rustc::ty::layout::{Integer, IntegerExt, Size};
 use syntax::attr::{SignedInt, UnsignedInt};
@@ -58,9 +58,11 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
         match *match_pair.pattern.kind {
             PatternKind::AscribeUserType {
                 ref subpattern,
-                variance,
-                ref user_ty,
-                user_ty_span
+                ascription: hair::pattern::Ascription {
+                    variance,
+                    ref user_ty,
+                    user_ty_span,
+                },
             } => {
                 // Apply the type ascription to the value at `match_pair.place`, which is the
                 // value being matched, taking the variance field into account.
diff --git a/src/librustc_mir/hair/cx/block.rs b/src/librustc_mir/hair/cx/block.rs
index 38c3e68a441f4..4a64ddb73fc2e 100644
--- a/src/librustc_mir/hair/cx/block.rs
+++ b/src/librustc_mir/hair/cx/block.rs
@@ -1,4 +1,4 @@
-use crate::hair::*;
+use crate::hair::{self, *};
 use crate::hair::cx::Cx;
 use crate::hair::cx::to_ref::ToRef;
 use rustc::middle::region;
@@ -83,10 +83,12 @@ fn mirror_stmts<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
                             ty: pattern.ty,
                             span: pattern.span,
                             kind: Box::new(PatternKind::AscribeUserType {
-                                user_ty: PatternTypeProjection::from_user_type(user_ty),
-                                user_ty_span: ty.span,
+                                ascription: hair::pattern::Ascription {
+                                    user_ty: PatternTypeProjection::from_user_type(user_ty),
+                                    user_ty_span: ty.span,
+                                    variance: ty::Variance::Covariant,
+                                },
                                 subpattern: pattern,
-                                variance: ty::Variance::Covariant,
                             })
                         };
                     }
diff --git a/src/librustc_mir/hair/pattern/_match.rs b/src/librustc_mir/hair/pattern/_match.rs
index c52a57e17c60b..1c7e1aa4d71e0 100644
--- a/src/librustc_mir/hair/pattern/_match.rs
+++ b/src/librustc_mir/hair/pattern/_match.rs
@@ -871,18 +871,24 @@ impl<'tcx> IntRange<'tcx> {
     }
 
     fn from_pat(tcx: TyCtxt<'_, 'tcx, 'tcx>,
-                pat: &Pattern<'tcx>)
+                mut pat: &Pattern<'tcx>)
                 -> Option<IntRange<'tcx>> {
-        Self::from_ctor(tcx, &match pat.kind {
-            box PatternKind::Constant { value } => ConstantValue(value),
-            box PatternKind::Range(PatternRange { lo, hi, ty, end }) => ConstantRange(
-                lo.to_bits(tcx, ty::ParamEnv::empty().and(ty)).unwrap(),
-                hi.to_bits(tcx, ty::ParamEnv::empty().and(ty)).unwrap(),
-                ty,
-                end,
-            ),
-            _ => return None,
-        })
+        let range = loop {
+            match pat.kind {
+                box PatternKind::Constant { value } => break ConstantValue(value),
+                box PatternKind::Range(PatternRange { lo, hi, ty, end }) => break ConstantRange(
+                    lo.to_bits(tcx, ty::ParamEnv::empty().and(ty)).unwrap(),
+                    hi.to_bits(tcx, ty::ParamEnv::empty().and(ty)).unwrap(),
+                    ty,
+                    end,
+                ),
+                box PatternKind::AscribeUserType { ref subpattern, .. } => {
+                    pat = subpattern;
+                },
+                _ => return None,
+            }
+        };
+        Self::from_ctor(tcx, &range)
     }
 
     // The return value of `signed_bias` should be XORed with an endpoint to encode/decode it.
diff --git a/src/librustc_mir/hair/pattern/mod.rs b/src/librustc_mir/hair/pattern/mod.rs
index fc3af3295cc11..2012086ea6649 100644
--- a/src/librustc_mir/hair/pattern/mod.rs
+++ b/src/librustc_mir/hair/pattern/mod.rs
@@ -58,7 +58,7 @@ pub struct Pattern<'tcx> {
 }
 
 
-#[derive(Clone, Debug)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub struct PatternTypeProjection<'tcx> {
     pub user_ty: CanonicalUserType<'tcx>,
 }
@@ -87,33 +87,38 @@ impl<'tcx> PatternTypeProjection<'tcx> {
     }
 }
 
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub struct Ascription<'tcx> {
+    pub user_ty: PatternTypeProjection<'tcx>,
+    /// Variance to use when relating the type `user_ty` to the **type of the value being
+    /// matched**. Typically, this is `Variance::Covariant`, since the value being matched must
+    /// have a type that is some subtype of the ascribed type.
+    ///
+    /// Note that this variance does not apply for any bindings within subpatterns. The type
+    /// assigned to those bindings must be exactly equal to the `user_ty` given here.
+    ///
+    /// The only place where this field is not `Covariant` is when matching constants, where
+    /// we currently use `Contravariant` -- this is because the constant type just needs to
+    /// be "comparable" to the type of the input value. So, for example:
+    ///
+    /// ```text
+    /// match x { "foo" => .. }
+    /// ```
+    ///
+    /// requires that `&'static str <: T_x`, where `T_x` is the type of `x`. Really, we should
+    /// probably be checking for a `PartialEq` impl instead, but this preserves the behavior
+    /// of the old type-check for now. See #57280 for details.
+    pub variance: ty::Variance,
+    pub user_ty_span: Span,
+}
+
 #[derive(Clone, Debug)]
 pub enum PatternKind<'tcx> {
     Wild,
 
     AscribeUserType {
-        user_ty: PatternTypeProjection<'tcx>,
+        ascription: Ascription<'tcx>,
         subpattern: Pattern<'tcx>,
-        /// Variance to use when relating the type `user_ty` to the **type of the value being
-        /// matched**. Typically, this is `Variance::Covariant`, since the value being matched must
-        /// have a type that is some subtype of the ascribed type.
-        ///
-        /// Note that this variance does not apply for any bindings within subpatterns. The type
-        /// assigned to those bindings must be exactly equal to the `user_ty` given here.
-        ///
-        /// The only place where this field is not `Covariant` is when matching constants, where
-        /// we currently use `Contravariant` -- this is because the constant type just needs to
-        /// be "comparable" to the type of the input value. So, for example:
-        ///
-        /// ```text
-        /// match x { "foo" => .. }
-        /// ```
-        ///
-        /// requires that `&'static str <: T_x`, where `T_x` is the type of `x`. Really, we should
-        /// probably be checking for a `PartialEq` impl instead, but this preserves the behavior
-        /// of the old type-check for now. See #57280 for details.
-        variance: ty::Variance,
-        user_ty_span: Span,
     },
 
     /// `x`, `ref x`, `x @ P`, etc.
@@ -169,18 +174,7 @@ pub enum PatternKind<'tcx> {
     },
 }
 
-impl<'tcx> PatternKind<'tcx> {
-    /// If this is a `PatternKind::AscribeUserType` then return the subpattern kind, otherwise
-    /// return this pattern kind.
-    fn with_user_type_ascription_subpattern(self) -> Self {
-        match self {
-            PatternKind::AscribeUserType { subpattern: Pattern { box kind, ..  }, ..  } => kind,
-            kind => kind,
-        }
-    }
-}
-
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub struct PatternRange<'tcx> {
     pub lo: ty::Const<'tcx>,
     pub hi: ty::Const<'tcx>,
@@ -407,6 +401,19 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
             )
     }
 
+    fn lower_range_expr(
+        &mut self,
+        expr: &'tcx hir::Expr,
+    ) -> (PatternKind<'tcx>, Option<Ascription<'tcx>>) {
+        match self.lower_lit(expr) {
+            PatternKind::AscribeUserType {
+                ascription: lo_ascription,
+                subpattern: Pattern { kind: box kind, .. },
+            } => (kind, Some(lo_ascription)),
+            kind => (kind, None),
+        }
+    }
+
     fn lower_pattern_unadjusted(&mut self, pat: &'tcx hir::Pat) -> Pattern<'tcx> {
         let mut ty = self.tables.node_type(pat.hir_id);
 
@@ -416,14 +423,10 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
             PatKind::Lit(ref value) => self.lower_lit(value),
 
             PatKind::Range(ref lo_expr, ref hi_expr, end) => {
-                match (
-                    // Look for `PatternKind::Constant` patterns inside of any
-                    // `PatternKind::AscribeUserType` patterns. Type ascriptions can be safely
-                    // ignored for the purposes of lowering a range correctly - these are checked
-                    // elsewhere for well-formedness.
-                    self.lower_lit(lo_expr).with_user_type_ascription_subpattern(),
-                    self.lower_lit(hi_expr).with_user_type_ascription_subpattern(),
-                ) {
+                let (lo, lo_ascription) = self.lower_range_expr(lo_expr);
+                let (hi, hi_ascription) = self.lower_range_expr(hi_expr);
+
+                let mut kind = match (lo, hi) {
                     (PatternKind::Constant { value: lo }, PatternKind::Constant { value: hi }) => {
                         use std::cmp::Ordering;
                         let cmp = compare_const_vals(
@@ -472,17 +475,33 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
                                 PatternKind::Wild
                             }
                         }
-                    }
+                    },
                     ref pats => {
                         self.tcx.sess.delay_span_bug(
                             pat.span,
-                            &format!("found bad range pattern `{:?}` outside of error recovery",
-                                     pats),
+                            &format!(
+                                "found bad range pattern `{:?}` outside of error recovery",
+                                pats,
+                            ),
                         );
 
                         PatternKind::Wild
+                    },
+                };
+
+                // If we are handling a range with associated constants (e.g.
+                // `Foo::<'a>::A..=Foo::B`), we need to put the ascriptions for the associated
+                // constants somewhere. Have them on the range pattern.
+                for ascription in &[lo_ascription, hi_ascription] {
+                    if let Some(ascription) = ascription {
+                        kind = PatternKind::AscribeUserType {
+                            ascription: *ascription,
+                            subpattern: Pattern { span: pat.span, ty, kind: Box::new(kind), },
+                        };
                     }
                 }
+
+                kind
             }
 
             PatKind::Path(ref qpath) => {
@@ -758,9 +777,11 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
                     ty,
                     kind: Box::new(kind),
                 },
-                user_ty: PatternTypeProjection::from_user_type(user_ty),
-                user_ty_span: span,
-                variance: ty::Variance::Covariant,
+                ascription: Ascription {
+                    user_ty: PatternTypeProjection::from_user_type(user_ty),
+                    user_ty_span: span,
+                    variance: ty::Variance::Covariant,
+                },
             };
         }
 
@@ -810,11 +831,13 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
                                         kind: Box::new(
                                             PatternKind::AscribeUserType {
                                                 subpattern: pattern,
-                                                /// Note that use `Contravariant` here. See the
-                                                /// `variance` field documentation for details.
-                                                variance: ty::Variance::Contravariant,
-                                                user_ty,
-                                                user_ty_span: span,
+                                                ascription: Ascription {
+                                                    /// Note that use `Contravariant` here. See the
+                                                    /// `variance` field documentation for details.
+                                                    variance: ty::Variance::Contravariant,
+                                                    user_ty,
+                                                    user_ty_span: span,
+                                                },
                                             }
                                         ),
                                         ty: value.ty,
@@ -1107,14 +1130,18 @@ impl<'tcx> PatternFoldable<'tcx> for PatternKind<'tcx> {
             PatternKind::Wild => PatternKind::Wild,
             PatternKind::AscribeUserType {
                 ref subpattern,
-                variance,
-                ref user_ty,
-                user_ty_span,
+                ascription: Ascription {
+                    variance,
+                    ref user_ty,
+                    user_ty_span,
+                },
             } => PatternKind::AscribeUserType {
                 subpattern: subpattern.fold_with(folder),
-                user_ty: user_ty.fold_with(folder),
-                variance,
-                user_ty_span,
+                ascription: Ascription {
+                    user_ty: user_ty.fold_with(folder),
+                    variance,
+                    user_ty_span,
+                },
             },
             PatternKind::Binding {
                 mutability,
diff --git a/src/rustllvm/PassWrapper.cpp b/src/rustllvm/PassWrapper.cpp
index 18d277be21a16..25595e14982ae 100644
--- a/src/rustllvm/PassWrapper.cpp
+++ b/src/rustllvm/PassWrapper.cpp
@@ -1092,10 +1092,10 @@ LLVMRustThinLTOBufferLen(const LLVMRustThinLTOBuffer *Buffer) {
 // processing.  We'll call this once per module optimized through ThinLTO, and
 // it'll be called concurrently on many threads.
 extern "C" LLVMModuleRef
-LLVMRustParseBitcodeForThinLTO(LLVMContextRef Context,
-                               const char *data,
-                               size_t len,
-                               const char *identifier) {
+LLVMRustParseBitcodeForLTO(LLVMContextRef Context,
+                           const char *data,
+                           size_t len,
+                           const char *identifier) {
   StringRef Data(data, len);
   MemoryBufferRef Buffer(Data, identifier);
   unwrap(Context)->enableDebugTypeODRUniquing();
diff --git a/src/test/incremental/lto.rs b/src/test/incremental/lto.rs
new file mode 100644
index 0000000000000..2a3e3c2467cdc
--- /dev/null
+++ b/src/test/incremental/lto.rs
@@ -0,0 +1,40 @@
+// no-prefer-dynamic
+// revisions:rpass1 rpass2
+// compile-flags: -C lto
+
+mod x {
+    pub struct X {
+        x: u32, y: u32,
+    }
+
+    #[cfg(rpass1)]
+    fn make() -> X {
+        X { x: 22, y: 0 }
+    }
+
+    #[cfg(rpass2)]
+    fn make() -> X {
+        X { x: 11, y: 11 }
+    }
+
+    pub fn new() -> X {
+        make()
+    }
+
+    pub fn sum(x: &X) -> u32 {
+        x.x + x.y
+    }
+}
+
+mod y {
+    use x;
+
+    pub fn assert_sum() -> bool {
+        let x = x::new();
+        x::sum(&x) == 22
+    }
+}
+
+pub fn main() {
+    y::assert_sum();
+}
diff --git a/src/test/ui/lint/lint-group-nonstandard-style.rs b/src/test/ui/lint/lint-group-nonstandard-style.rs
index 0386daaa59b07..bd7f327bc0f63 100644
--- a/src/test/ui/lint/lint-group-nonstandard-style.rs
+++ b/src/test/ui/lint/lint-group-nonstandard-style.rs
@@ -19,7 +19,7 @@ mod test {
 
         fn CamelCase() {} //~ WARN should have a snake
 
-        struct snake_case; //~ WARN should have a camel
+        struct snake_case; //~ WARN should have an upper camel
     }
 }
 
diff --git a/src/test/ui/lint/lint-group-nonstandard-style.stderr b/src/test/ui/lint/lint-group-nonstandard-style.stderr
index f3c7d70054b77..ab36cda57ec80 100644
--- a/src/test/ui/lint/lint-group-nonstandard-style.stderr
+++ b/src/test/ui/lint/lint-group-nonstandard-style.stderr
@@ -1,8 +1,8 @@
-warning: type `snake_case` should have a camel case name
+warning: type `snake_case` should have an upper camel case name
   --> $DIR/lint-group-nonstandard-style.rs:22:16
    |
-LL |         struct snake_case; //~ WARN should have a camel
-   |                ^^^^^^^^^^ help: convert the identifier to camel case: `SnakeCase`
+LL |         struct snake_case; //~ WARN should have an upper camel
+   |                ^^^^^^^^^^ help: convert the identifier to upper camel case: `SnakeCase`
    |
 note: lint level defined here
   --> $DIR/lint-group-nonstandard-style.rs:18:17
diff --git a/src/test/ui/lint/lint-non-camel-case-types.rs b/src/test/ui/lint/lint-non-camel-case-types.rs
index bca1992605b77..d3b119a944109 100644
--- a/src/test/ui/lint/lint-non-camel-case-types.rs
+++ b/src/test/ui/lint/lint-non-camel-case-types.rs
@@ -2,43 +2,35 @@
 #![allow(dead_code)]
 
 struct ONE_TWO_THREE;
-//~^ ERROR type `ONE_TWO_THREE` should have a camel case name
+//~^ ERROR type `ONE_TWO_THREE` should have an upper camel case name
 
-struct foo { //~ ERROR type `foo` should have a camel case name
+struct foo { //~ ERROR type `foo` should have an upper camel case name
     bar: isize,
 }
 
-enum foo2 { //~ ERROR type `foo2` should have a camel case name
+enum foo2 { //~ ERROR type `foo2` should have an upper camel case name
     Bar
 }
 
-struct foo3 { //~ ERROR type `foo3` should have a camel case name
+struct foo3 { //~ ERROR type `foo3` should have an upper camel case name
     bar: isize
 }
 
-type foo4 = isize; //~ ERROR type `foo4` should have a camel case name
+type foo4 = isize; //~ ERROR type `foo4` should have an upper camel case name
 
 enum Foo5 {
-    bar //~ ERROR variant `bar` should have a camel case name
+    bar //~ ERROR variant `bar` should have an upper camel case name
 }
 
-trait foo6 { //~ ERROR trait `foo6` should have a camel case name
+trait foo6 { //~ ERROR trait `foo6` should have an upper camel case name
     fn dummy(&self) { }
 }
 
-fn f<ty>(_: ty) {} //~ ERROR type parameter `ty` should have a camel case name
+fn f<ty>(_: ty) {} //~ ERROR type parameter `ty` should have an upper camel case name
 
 #[repr(C)]
 struct foo7 {
     bar: isize,
 }
 
-struct X86_64;
-
-struct X86__64; //~ ERROR type `X86__64` should have a camel case name
-
-struct Abc_123; //~ ERROR type `Abc_123` should have a camel case name
-
-struct A1_b2_c3; //~ ERROR type `A1_b2_c3` should have a camel case name
-
 fn main() { }
diff --git a/src/test/ui/lint/lint-non-camel-case-types.stderr b/src/test/ui/lint/lint-non-camel-case-types.stderr
index 74f9a5993b859..7afacf64d8778 100644
--- a/src/test/ui/lint/lint-non-camel-case-types.stderr
+++ b/src/test/ui/lint/lint-non-camel-case-types.stderr
@@ -1,8 +1,8 @@
-error: type `ONE_TWO_THREE` should have a camel case name
+error: type `ONE_TWO_THREE` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:4:8
    |
 LL | struct ONE_TWO_THREE;
-   |        ^^^^^^^^^^^^^ help: convert the identifier to camel case: `OneTwoThree`
+   |        ^^^^^^^^^^^^^ help: convert the identifier to upper camel case: `OneTwoThree`
    |
 note: lint level defined here
   --> $DIR/lint-non-camel-case-types.rs:1:11
@@ -10,65 +10,47 @@ note: lint level defined here
 LL | #![forbid(non_camel_case_types)]
    |           ^^^^^^^^^^^^^^^^^^^^
 
-error: type `foo` should have a camel case name
+error: type `foo` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:7:8
    |
-LL | struct foo { //~ ERROR type `foo` should have a camel case name
-   |        ^^^ help: convert the identifier to camel case: `Foo`
+LL | struct foo { //~ ERROR type `foo` should have an upper camel case name
+   |        ^^^ help: convert the identifier to upper camel case: `Foo`
 
-error: type `foo2` should have a camel case name
+error: type `foo2` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:11:6
    |
-LL | enum foo2 { //~ ERROR type `foo2` should have a camel case name
-   |      ^^^^ help: convert the identifier to camel case: `Foo2`
+LL | enum foo2 { //~ ERROR type `foo2` should have an upper camel case name
+   |      ^^^^ help: convert the identifier to upper camel case: `Foo2`
 
-error: type `foo3` should have a camel case name
+error: type `foo3` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:15:8
    |
-LL | struct foo3 { //~ ERROR type `foo3` should have a camel case name
-   |        ^^^^ help: convert the identifier to camel case: `Foo3`
+LL | struct foo3 { //~ ERROR type `foo3` should have an upper camel case name
+   |        ^^^^ help: convert the identifier to upper camel case: `Foo3`
 
-error: type `foo4` should have a camel case name
+error: type `foo4` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:19:6
    |
-LL | type foo4 = isize; //~ ERROR type `foo4` should have a camel case name
-   |      ^^^^ help: convert the identifier to camel case: `Foo4`
+LL | type foo4 = isize; //~ ERROR type `foo4` should have an upper camel case name
+   |      ^^^^ help: convert the identifier to upper camel case: `Foo4`
 
-error: variant `bar` should have a camel case name
+error: variant `bar` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:22:5
    |
-LL |     bar //~ ERROR variant `bar` should have a camel case name
-   |     ^^^ help: convert the identifier to camel case: `Bar`
+LL |     bar //~ ERROR variant `bar` should have an upper camel case name
+   |     ^^^ help: convert the identifier to upper camel case: `Bar`
 
-error: trait `foo6` should have a camel case name
+error: trait `foo6` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:25:7
    |
-LL | trait foo6 { //~ ERROR trait `foo6` should have a camel case name
-   |       ^^^^ help: convert the identifier to camel case: `Foo6`
+LL | trait foo6 { //~ ERROR trait `foo6` should have an upper camel case name
+   |       ^^^^ help: convert the identifier to upper camel case: `Foo6`
 
-error: type parameter `ty` should have a camel case name
+error: type parameter `ty` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:29:6
    |
-LL | fn f<ty>(_: ty) {} //~ ERROR type parameter `ty` should have a camel case name
-   |      ^^ help: convert the identifier to camel case: `Ty`
+LL | fn f<ty>(_: ty) {} //~ ERROR type parameter `ty` should have an upper camel case name
+   |      ^^ help: convert the identifier to upper camel case: `Ty`
 
-error: type `X86__64` should have a camel case name
-  --> $DIR/lint-non-camel-case-types.rs:38:8
-   |
-LL | struct X86__64; //~ ERROR type `X86__64` should have a camel case name
-   |        ^^^^^^^ help: convert the identifier to camel case: `X86_64`
-
-error: type `Abc_123` should have a camel case name
-  --> $DIR/lint-non-camel-case-types.rs:40:8
-   |
-LL | struct Abc_123; //~ ERROR type `Abc_123` should have a camel case name
-   |        ^^^^^^^ help: convert the identifier to camel case: `Abc123`
-
-error: type `A1_b2_c3` should have a camel case name
-  --> $DIR/lint-non-camel-case-types.rs:42:8
-   |
-LL | struct A1_b2_c3; //~ ERROR type `A1_b2_c3` should have a camel case name
-   |        ^^^^^^^^ help: convert the identifier to camel case: `A1B2C3`
-
-error: aborting due to 11 previous errors
+error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/nll/closure-requirements/issue-58127-mutliple-requirements.rs b/src/test/ui/nll/closure-requirements/issue-58127-mutliple-requirements.rs
new file mode 100644
index 0000000000000..71d5d4053ee25
--- /dev/null
+++ b/src/test/ui/nll/closure-requirements/issue-58127-mutliple-requirements.rs
@@ -0,0 +1,40 @@
+// revisions: migrate nll
+//[migrate]compile-flags: -Z borrowck=migrate
+#![cfg_attr(nll, feature(nll))]
+
+// compile-pass
+
+// Test that we propagate region relations from closures precisely when there is
+// more than one non-local lower bound.
+
+// In this case the closure has signature
+// |x: &'4 mut (&'5 (&'1 str, &'2 str), &'3 str)| -> ..
+// We end up with a `'3: '5` constraint that we can propagate as
+// `'3: '1`, `'3: '2`, but previously we approximated it as `'3: 'static`.
+
+// As an optimization, we primarily propagate bounds for the "representative"
+// of each SCC. As such we have these two similar cases where hopefully one
+// of them will test the case we want (case2, when this test was added).
+mod case1 {
+    fn f(s: &str) {
+        g(s, |x| h(x));
+    }
+
+    fn g<T, F>(_: T, _: F)
+    where F: Fn(&mut (&(T, T), T)) {}
+
+    fn h<T>(_: &mut (&(T, T), T)) {}
+}
+
+mod case2 {
+    fn f(s: &str) {
+        g(s, |x| h(x));
+    }
+
+    fn g<T, F>(_: T, _: F)
+    where F: Fn(&mut (T, &(T, T))) {}
+
+    fn h<T>(_: &mut (T, &(T, T))) {}
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/issue-58299.rs b/src/test/ui/nll/issue-58299.rs
new file mode 100644
index 0000000000000..9267cac5dd3d7
--- /dev/null
+++ b/src/test/ui/nll/issue-58299.rs
@@ -0,0 +1,30 @@
+#![allow(dead_code)]
+#![feature(nll)]
+
+struct A<'a>(&'a ());
+
+trait Y {
+    const X: i32;
+}
+
+impl Y for A<'static> {
+    const X: i32 = 10;
+}
+
+fn foo<'a>(x: i32) {
+    match x {
+        // This uses <A<'a> as Y>::X, but `A<'a>` does not implement `Y`.
+        A::<'a>::X..=A::<'static>::X => (), //~ ERROR lifetime may not live long enough
+        _ => (),
+    }
+}
+
+fn bar<'a>(x: i32) {
+    match x {
+        // This uses <A<'a> as Y>::X, but `A<'a>` does not implement `Y`.
+        A::<'static>::X..=A::<'a>::X => (), //~ ERROR lifetime may not live long enough
+        _ => (),
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/issue-58299.stderr b/src/test/ui/nll/issue-58299.stderr
new file mode 100644
index 0000000000000..b87d0de51a37e
--- /dev/null
+++ b/src/test/ui/nll/issue-58299.stderr
@@ -0,0 +1,20 @@
+error: lifetime may not live long enough
+  --> $DIR/issue-58299.rs:17:9
+   |
+LL | fn foo<'a>(x: i32) {
+   |        -- lifetime `'a` defined here
+...
+LL |         A::<'a>::X..=A::<'static>::X => (), //~ ERROR lifetime may not live long enough
+   |         ^^^^^^^^^^ requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/issue-58299.rs:25:27
+   |
+LL | fn bar<'a>(x: i32) {
+   |        -- lifetime `'a` defined here
+...
+LL |         A::<'static>::X..=A::<'a>::X => (), //~ ERROR lifetime may not live long enough
+   |                           ^^^^^^^^^^ requires that `'a` must outlive `'static`
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/utf8_idents.rs b/src/test/ui/utf8_idents.rs
index e601c6e455544..f59d5502aae30 100644
--- a/src/test/ui/utf8_idents.rs
+++ b/src/test/ui/utf8_idents.rs
@@ -1,9 +1,7 @@
-//
-
 fn foo<
     'β, //~ ERROR non-ascii idents are not fully supported
     γ  //~ ERROR non-ascii idents are not fully supported
-       //~^ WARN type parameter `γ` should have a camel case name
+       //~^ WARN type parameter `γ` should have an upper camel case name
 >() {}
 
 struct X {
diff --git a/src/test/ui/utf8_idents.stderr b/src/test/ui/utf8_idents.stderr
index 268dd99d06031..52fb607af5b25 100644
--- a/src/test/ui/utf8_idents.stderr
+++ b/src/test/ui/utf8_idents.stderr
@@ -1,5 +1,5 @@
 error[E0658]: non-ascii idents are not fully supported. (see issue #55467)
-  --> $DIR/utf8_idents.rs:4:5
+  --> $DIR/utf8_idents.rs:2:5
    |
 LL |     'β, //~ ERROR non-ascii idents are not fully supported
    |     ^^
@@ -7,7 +7,7 @@ LL |     'β, //~ ERROR non-ascii idents are not fully supported
    = help: add #![feature(non_ascii_idents)] to the crate attributes to enable
 
 error[E0658]: non-ascii idents are not fully supported. (see issue #55467)
-  --> $DIR/utf8_idents.rs:5:5
+  --> $DIR/utf8_idents.rs:3:5
    |
 LL |     γ  //~ ERROR non-ascii idents are not fully supported
    |     ^
@@ -15,7 +15,7 @@ LL |     γ  //~ ERROR non-ascii idents are not fully supported
    = help: add #![feature(non_ascii_idents)] to the crate attributes to enable
 
 error[E0658]: non-ascii idents are not fully supported. (see issue #55467)
-  --> $DIR/utf8_idents.rs:10:5
+  --> $DIR/utf8_idents.rs:8:5
    |
 LL |     δ: usize //~ ERROR non-ascii idents are not fully supported
    |     ^
@@ -23,18 +23,18 @@ LL |     δ: usize //~ ERROR non-ascii idents are not fully supported
    = help: add #![feature(non_ascii_idents)] to the crate attributes to enable
 
 error[E0658]: non-ascii idents are not fully supported. (see issue #55467)
-  --> $DIR/utf8_idents.rs:14:9
+  --> $DIR/utf8_idents.rs:12:9
    |
 LL |     let α = 0.00001f64; //~ ERROR non-ascii idents are not fully supported
    |         ^
    |
    = help: add #![feature(non_ascii_idents)] to the crate attributes to enable
 
-warning: type parameter `γ` should have a camel case name
-  --> $DIR/utf8_idents.rs:5:5
+warning: type parameter `γ` should have an upper camel case name
+  --> $DIR/utf8_idents.rs:3:5
    |
 LL |     γ  //~ ERROR non-ascii idents are not fully supported
-   |     ^ help: convert the identifier to camel case: `Γ`
+   |     ^ help: convert the identifier to upper camel case: `Γ`
    |
    = note: #[warn(non_camel_case_types)] on by default
 
diff --git a/src/tools/publish_toolstate.py b/src/tools/publish_toolstate.py
index ed697fc542535..24d6fd5b19ba9 100755
--- a/src/tools/publish_toolstate.py
+++ b/src/tools/publish_toolstate.py
@@ -17,7 +17,7 @@
     'miri': '@oli-obk @RalfJung @eddyb',
     'clippy-driver': '@Manishearth @llogiq @mcarton @oli-obk',
     'rls': '@nrc @Xanewok',
-    'rustfmt': '@nrc',
+    'rustfmt': '@nrc @topecongiro',
     'book': '@carols10cents @steveklabnik',
     'nomicon': '@frewsxcv @Gankro',
     'reference': '@steveklabnik @Havvy @matthewjasper @alercah',