diff --git a/Cargo.lock b/Cargo.lock
index c105d04c1f440..23481488563bd 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -473,9 +473,9 @@ version = "0.1.0"
 
 [[package]]
 name = "cc"
-version = "1.0.73"
+version = "1.0.76"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2fff2a6927b3bb87f9595d67196a70493f627687a71d87a0d692242c33f58c11"
+checksum = "76a284da2e6fe2092f2353e51713435363112dfd60030e22add80be333fb928f"
 dependencies = [
  "jobserver",
 ]
diff --git a/compiler/rustc_codegen_llvm/src/back/write.rs b/compiler/rustc_codegen_llvm/src/back/write.rs
index 11053a8f6c452..97d0de47b3a6e 100644
--- a/compiler/rustc_codegen_llvm/src/back/write.rs
+++ b/compiler/rustc_codegen_llvm/src/back/write.rs
@@ -765,11 +765,21 @@ pub(crate) unsafe fn codegen(
         drop(handlers);
     }
 
+    // `.dwo` files are only emitted if:
+    //
+    // - Object files are being emitted (i.e. bitcode only or metadata only compilations will not
+    //   produce dwarf objects, even if otherwise enabled)
+    // - Target supports Split DWARF
+    // - Split debuginfo is enabled
+    // - Split DWARF kind is `split` (i.e. debuginfo is split into `.dwo` files, not different
+    //   sections in the `.o` files).
+    let dwarf_object_emitted = matches!(config.emit_obj, EmitObj::ObjectCode(_))
+        && cgcx.target_can_use_split_dwarf
+        && cgcx.split_debuginfo != SplitDebuginfo::Off
+        && cgcx.split_dwarf_kind == SplitDwarfKind::Split;
     Ok(module.into_compiled_module(
         config.emit_obj != EmitObj::None,
-        cgcx.target_can_use_split_dwarf
-            && cgcx.split_debuginfo != SplitDebuginfo::Off
-            && cgcx.split_dwarf_kind == SplitDwarfKind::Split,
+        dwarf_object_emitted,
         config.emit_bc,
         &cgcx.output_filenames,
     ))
diff --git a/compiler/rustc_llvm/build.rs b/compiler/rustc_llvm/build.rs
index 28e092c1eb72c..d35e4191cc0b1 100644
--- a/compiler/rustc_llvm/build.rs
+++ b/compiler/rustc_llvm/build.rs
@@ -334,7 +334,7 @@ fn main() {
         "c++"
     } else if target.contains("netbsd") && llvm_static_stdcpp.is_some() {
         // NetBSD uses a separate library when relocation is required
-        "stdc++_pic"
+        "stdc++_p"
     } else if llvm_use_libcxx.is_some() {
         "c++"
     } else {
diff --git a/compiler/rustc_parse/src/parser/attr_wrapper.rs b/compiler/rustc_parse/src/parser/attr_wrapper.rs
index 1b16ecb5ec2d6..c8160548763c8 100644
--- a/compiler/rustc_parse/src/parser/attr_wrapper.rs
+++ b/compiler/rustc_parse/src/parser/attr_wrapper.rs
@@ -5,7 +5,8 @@ use rustc_ast::tokenstream::{AttrTokenTree, DelimSpan, LazyAttrTokenStream, Spac
 use rustc_ast::{self as ast};
 use rustc_ast::{AttrVec, Attribute, HasAttrs, HasTokens};
 use rustc_errors::PResult;
-use rustc_span::{sym, Span};
+use rustc_session::parse::ParseSess;
+use rustc_span::{sym, Span, DUMMY_SP};
 
 use std::convert::TryInto;
 use std::ops::Range;
@@ -39,8 +40,13 @@ impl AttrWrapper {
     pub fn empty() -> AttrWrapper {
         AttrWrapper { attrs: AttrVec::new(), start_pos: usize::MAX }
     }
-    // FIXME: Delay span bug here?
-    pub(crate) fn take_for_recovery(self) -> AttrVec {
+
+    pub(crate) fn take_for_recovery(self, sess: &ParseSess) -> AttrVec {
+        sess.span_diagnostic.delay_span_bug(
+            self.attrs.get(0).map(|attr| attr.span).unwrap_or(DUMMY_SP),
+            "AttrVec is taken for recovery but no error is produced",
+        );
+
         self.attrs
     }
 
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 7355730c9ebf1..b072573af23f0 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -2272,7 +2272,7 @@ impl<'a> Parser<'a> {
                 self.mk_block_err(cond_span.shrink_to_hi())
             }
         } else {
-            let attrs = self.parse_outer_attributes()?.take_for_recovery(); // For recovery.
+            let attrs = self.parse_outer_attributes()?; // For recovery.
             let block = if self.check(&token::OpenDelim(Delimiter::Brace)) {
                 self.parse_block()?
             } else {
@@ -2289,7 +2289,7 @@ impl<'a> Parser<'a> {
                     })?
                 }
             };
-            self.error_on_if_block_attrs(lo, false, block.span, &attrs);
+            self.error_on_if_block_attrs(lo, false, block.span, attrs);
             block
         };
         let els = if self.eat_keyword(kw::Else) { Some(self.parse_else_expr()?) } else { None };
@@ -2350,7 +2350,7 @@ impl<'a> Parser<'a> {
     /// Parses an `else { ... }` expression (`else` token already eaten).
     fn parse_else_expr(&mut self) -> PResult<'a, P<Expr>> {
         let else_span = self.prev_token.span; // `else`
-        let attrs = self.parse_outer_attributes()?.take_for_recovery(); // For recovery.
+        let attrs = self.parse_outer_attributes()?; // For recovery.
         let expr = if self.eat_keyword(kw::If) {
             self.parse_if_expr()?
         } else if self.check(&TokenKind::OpenDelim(Delimiter::Brace)) {
@@ -2385,7 +2385,7 @@ impl<'a> Parser<'a> {
                 },
             }
         };
-        self.error_on_if_block_attrs(else_span, true, expr.span, &attrs);
+        self.error_on_if_block_attrs(else_span, true, expr.span, attrs);
         Ok(expr)
     }
 
@@ -2394,8 +2394,13 @@ impl<'a> Parser<'a> {
         ctx_span: Span,
         is_ctx_else: bool,
         branch_span: Span,
-        attrs: &[ast::Attribute],
+        attrs: AttrWrapper,
     ) {
+        if attrs.is_empty() {
+            return;
+        }
+
+        let attrs: &[ast::Attribute] = &attrs.take_for_recovery(self.sess);
         let (attributes, last) = match attrs {
             [] => return,
             [x0 @ xn] | [x0, .., xn] => (x0.span.to(xn.span), xn.span),
diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs
index 12753c6785c9a..9684145ad9948 100644
--- a/compiler/rustc_parse/src/parser/stmt.rs
+++ b/compiler/rustc_parse/src/parser/stmt.rs
@@ -19,7 +19,7 @@ use rustc_ast as ast;
 use rustc_ast::ptr::P;
 use rustc_ast::token::{self, Delimiter, TokenKind};
 use rustc_ast::util::classify;
-use rustc_ast::{AttrStyle, AttrVec, Attribute, LocalKind, MacCall, MacCallStmt, MacStmtStyle};
+use rustc_ast::{AttrStyle, AttrVec, LocalKind, MacCall, MacCallStmt, MacStmtStyle};
 use rustc_ast::{Block, BlockCheckMode, Expr, ExprKind, HasAttrs, Local, Stmt};
 use rustc_ast::{StmtKind, DUMMY_NODE_ID};
 use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, PResult};
@@ -101,7 +101,7 @@ impl<'a> Parser<'a> {
             self.mk_stmt(lo.to(item.span), StmtKind::Item(P(item)))
         } else if self.eat(&token::Semi) {
             // Do not attempt to parse an expression if we're done here.
-            self.error_outer_attrs(&attrs.take_for_recovery());
+            self.error_outer_attrs(attrs);
             self.mk_stmt(lo, StmtKind::Empty)
         } else if self.token != token::CloseDelim(Delimiter::Brace) {
             // Remainder are line-expr stmts.
@@ -120,7 +120,7 @@ impl<'a> Parser<'a> {
             }
             self.mk_stmt(lo.to(e.span), StmtKind::Expr(e))
         } else {
-            self.error_outer_attrs(&attrs.take_for_recovery());
+            self.error_outer_attrs(attrs);
             return Ok(None);
         }))
     }
@@ -199,8 +199,10 @@ impl<'a> Parser<'a> {
 
     /// Error on outer attributes in this context.
     /// Also error if the previous token was a doc comment.
-    fn error_outer_attrs(&self, attrs: &[Attribute]) {
-        if let [.., last] = attrs {
+    fn error_outer_attrs(&self, attrs: AttrWrapper) {
+        if !attrs.is_empty()
+        && let attrs = attrs.take_for_recovery(self.sess)
+        && let attrs @ [.., last] = &*attrs {
             if last.is_doc_comment() {
                 self.sess.emit_err(DocCommentDoesNotDocumentAnything {
                     span: last.span,
diff --git a/library/std/src/path.rs b/library/std/src/path.rs
index 9d63281627d66..af88b9070c189 100644
--- a/library/std/src/path.rs
+++ b/library/std/src/path.rs
@@ -2142,7 +2142,10 @@ impl Path {
 
     /// Returns the `Path` without its final component, if there is one.
     ///
-    /// Returns [`None`] if the path terminates in a root or prefix.
+    /// This means it returns `Some("")` for relative paths with one component.
+    ///
+    /// Returns [`None`] if the path terminates in a root or prefix, or if it's
+    /// the empty string.
     ///
     /// # Examples
     ///
@@ -2156,6 +2159,14 @@ impl Path {
     /// let grand_parent = parent.parent().unwrap();
     /// assert_eq!(grand_parent, Path::new("/"));
     /// assert_eq!(grand_parent.parent(), None);
+    ///
+    /// let relative_path = Path::new("foo/bar");
+    /// let parent = relative_path.parent();
+    /// assert_eq!(parent, Some(Path::new("foo")));
+    /// let grand_parent = parent.and_then(Path::parent);
+    /// assert_eq!(grand_parent, Some(Path::new("")));
+    /// let great_grand_parent = grand_parent.and_then(Path::parent);
+    /// assert_eq!(great_grand_parent, None);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[doc(alias = "dirname")]
diff --git a/library/unwind/Cargo.toml b/library/unwind/Cargo.toml
index 32c4a7eb5c18c..eab2717c45233 100644
--- a/library/unwind/Cargo.toml
+++ b/library/unwind/Cargo.toml
@@ -20,7 +20,7 @@ compiler_builtins = "0.1.0"
 cfg-if = "1.0"
 
 [build-dependencies]
-cc = "1.0.69"
+cc = "1.0.76"
 
 [features]
 
diff --git a/src/bootstrap/util.rs b/src/bootstrap/util.rs
index 8a2f46abbd23c..58220783228b2 100644
--- a/src/bootstrap/util.rs
+++ b/src/bootstrap/util.rs
@@ -44,7 +44,13 @@ pub use t;
 /// Given an executable called `name`, return the filename for the
 /// executable for a particular target.
 pub fn exe(name: &str, target: TargetSelection) -> String {
-    if target.contains("windows") { format!("{}.exe", name) } else { name.to_string() }
+    if target.contains("windows") {
+        format!("{}.exe", name)
+    } else if target.contains("uefi") {
+        format!("{}.efi", name)
+    } else {
+        name.to_string()
+    }
 }
 
 /// Returns `true` if the file name given looks like a dynamic library.
diff --git a/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile
index 7d77fdd30d1d8..43a449b3a1926 100644
--- a/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile
@@ -28,5 +28,5 @@ ENV \
 
 ENV HOSTS=s390x-unknown-linux-gnu
 
-ENV RUST_CONFIGURE_ARGS --enable-extended --enable-lld --disable-docs
+ENV RUST_CONFIGURE_ARGS --enable-extended --enable-lld --enable-profiler --disable-docs
 ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS
diff --git a/src/ci/docker/host-x86_64/dist-x86_64-netbsd/Dockerfile b/src/ci/docker/host-x86_64/dist-x86_64-netbsd/Dockerfile
index fed4be4c30a74..d03c364547e03 100644
--- a/src/ci/docker/host-x86_64/dist-x86_64-netbsd/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-x86_64-netbsd/Dockerfile
@@ -1,7 +1,8 @@
-FROM ubuntu:16.04
+FROM ubuntu:20.04
 
 COPY scripts/cross-apt-packages.sh /scripts/
 RUN sh /scripts/cross-apt-packages.sh
+RUN DEBIAN_FRONTEND=noninteractive apt-get install -y zlib1g-dev
 
 COPY host-x86_64/dist-x86_64-netbsd/build-netbsd-toolchain.sh /tmp/
 RUN /tmp/build-netbsd-toolchain.sh
@@ -9,9 +10,6 @@ RUN /tmp/build-netbsd-toolchain.sh
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
-COPY scripts/cmake.sh /scripts/
-RUN /scripts/cmake.sh
-
 ENV PATH=$PATH:/x-tools/x86_64-unknown-netbsd/bin
 
 ENV \
@@ -21,6 +19,5 @@ ENV \
 
 ENV HOSTS=x86_64-unknown-netbsd
 
-ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs \
-    --set llvm.allow-old-toolchain
+ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
 ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS
diff --git a/src/ci/docker/host-x86_64/dist-x86_64-netbsd/build-netbsd-toolchain.sh b/src/ci/docker/host-x86_64/dist-x86_64-netbsd/build-netbsd-toolchain.sh
index 5dfa47b4eed74..e0c008b76fa8b 100755
--- a/src/ci/docker/host-x86_64/dist-x86_64-netbsd/build-netbsd-toolchain.sh
+++ b/src/ci/docker/host-x86_64/dist-x86_64-netbsd/build-netbsd-toolchain.sh
@@ -25,19 +25,19 @@ cd netbsd
 
 mkdir -p /x-tools/x86_64-unknown-netbsd/sysroot
 
-URL=https://ci-mirrors.rust-lang.org/rustc
-
-# Originally from ftp://ftp.netbsd.org/pub/NetBSD/NetBSD-$BSD/source/sets/*.tgz
-curl $URL/2018-03-01-netbsd-src.tgz | tar xzf -
-curl $URL/2018-03-01-netbsd-gnusrc.tgz | tar xzf -
-curl $URL/2018-03-01-netbsd-sharesrc.tgz | tar xzf -
-curl $URL/2018-03-01-netbsd-syssrc.tgz | tar xzf -
-
-# Originally from ftp://ftp.netbsd.org/pub/NetBSD/NetBSD-$BSD/amd64/binary/sets/*.tgz
-curl $URL/2018-03-01-netbsd-base.tgz | \
-  tar xzf - -C /x-tools/x86_64-unknown-netbsd/sysroot ./usr/include ./usr/lib ./lib
-curl $URL/2018-03-01-netbsd-comp.tgz | \
-  tar xzf - -C /x-tools/x86_64-unknown-netbsd/sysroot ./usr/include ./usr/lib
+# URL=https://ci-mirrors.rust-lang.org/rustc
+
+SOURCE_URL=https://cdn.netbsd.org/pub/NetBSD/NetBSD-9.0/source/sets
+curl $SOURCE_URL/src.tgz | tar xzf -
+curl $SOURCE_URL/gnusrc.tgz | tar xzf -
+curl $SOURCE_URL/sharesrc.tgz | tar xzf -
+curl $SOURCE_URL/syssrc.tgz | tar xzf -
+
+BINARY_URL=https://cdn.netbsd.org/pub/NetBSD/NetBSD-9.0/amd64/binary/sets
+curl $BINARY_URL/base.tar.xz | \
+  tar xJf - -C /x-tools/x86_64-unknown-netbsd/sysroot ./usr/include ./usr/lib ./lib
+curl $BINARY_URL/comp.tar.xz | \
+  tar xJf - -C /x-tools/x86_64-unknown-netbsd/sysroot ./usr/include ./usr/lib
 
 cd usr/src
 
diff --git a/src/test/incremental/issue-101518.rs b/src/test/incremental/issue-101518.rs
new file mode 100644
index 0000000000000..501be175fce50
--- /dev/null
+++ b/src/test/incremental/issue-101518.rs
@@ -0,0 +1,31 @@
+// revisions: cfail1
+// should-ice
+// error-pattern: forcing query
+// known-bug: #101518
+
+#[derive(PartialEq, Eq)]
+struct Id<'a> {
+    ns: &'a str,
+}
+fn visit_struct() {
+    let id = Id { ns: "random1" };
+    const FLAG: Id<'static> = Id {
+        ns: "needs_to_be_the_same",
+    };
+    match id {
+        FLAG => {}
+        _ => {}
+    }
+}
+fn visit_struct2() {
+    let id = Id { ns: "random2" };
+    const FLAG: Id<'static> = Id {
+        ns: "needs_to_be_the_same",
+    };
+    match id {
+        FLAG => {}
+        _ => {}
+    }
+}
+
+fn main() {}
diff --git a/src/test/run-make-fulldeps/split-debuginfo/Makefile b/src/test/run-make-fulldeps/split-debuginfo/Makefile
index 1032f3408f062..1831ab38fab49 100644
--- a/src/test/run-make-fulldeps/split-debuginfo/Makefile
+++ b/src/test/run-make-fulldeps/split-debuginfo/Makefile
@@ -3,7 +3,7 @@ include ../tools.mk
 all: off packed unpacked
 
 ifeq ($(UNAME),Darwin)
-# If disabled, don't run dsymutil
+# If disabled, don't run `dsymutil`.
 off:
 	rm -rf $(TMPDIR)/*.dSYM
 	$(RUSTC) foo.rs -g -C split-debuginfo=off
@@ -29,98 +29,280 @@ unpacked:
 	[ ! -d $(TMPDIR)/foo.dSYM ]
 else
 ifdef IS_WINDOWS
-# Windows only supports =packed
+# Windows only supports packed debuginfo - nothing to test.
 off:
 packed:
 unpacked:
 else
+# Some non-Windows, non-Darwin platforms are not stable, and some are.
 ifeq ($(UNAME),Linux)
   UNSTABLEOPTS :=
 else
   UNSTABLEOPTS := -Zunstable-options
 endif
 
+# - Debuginfo in `.o` files
+# - `.o` deleted
+# - `.dwo` never created
+# - `.dwp` never created
 off:
 	$(RUSTC) foo.rs -g -C $(UNSTABLEOPTS) split-debuginfo=off
 	[ ! -f $(TMPDIR)/*.dwp ]
 	[ ! -f $(TMPDIR)/*.dwo ]
-
 	$(RUSTC) foo.rs -g
 	[ ! -f $(TMPDIR)/*.dwp ]
 	[ ! -f $(TMPDIR)/*.dwo ]
 
-packed: packed-split packed-single
+packed: packed-split packed-single packed-lto packed-remapped packed-crosscrate
 
+# - Debuginfo in `.dwo` files
+# - `.o` deleted
+# - `.dwo` deleted
+# - `.dwp` present
 packed-split:
 	$(RUSTC) foo.rs -g $(UNSTABLEOPTS) -C split-debuginfo=packed -Zsplit-dwarf-kind=split
-	ls $(TMPDIR)/*.dwp
-	rm -rf $(TMPDIR)/*.dwp $(TMPDIR)/*.dwo
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
+	rm $(TMPDIR)/foo.dwp
+	rm $(TMPDIR)/$(call BIN,foo)
 
+# - Debuginfo in `.o` files
+# - `.o` deleted
+# - `.dwo` never created
+# - `.dwp` present
 packed-single:
 	$(RUSTC) foo.rs -g $(UNSTABLEOPTS) -C split-debuginfo=packed -Zsplit-dwarf-kind=single
-	ls $(TMPDIR)/*.dwp
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
+	rm $(TMPDIR)/foo.dwp
+	rm $(TMPDIR)/$(call BIN,foo)
+
+packed-lto: packed-lto-split packed-lto-single
+
+# - rmeta file added to rlib, no object files are generated and thus no debuginfo is generated
+# - `.o` never created
+# - `.dwo` never created
+# - `.dwp` never created
+packed-lto-split:
+	$(RUSTC) baz.rs -g $(UNSTABLEOPTS) -Csplit-debuginfo=packed -Zsplit-dwarf-kind=split \
+		--crate-type=rlib -Clinker-plugin-lto
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
+	rm $(TMPDIR)/libbaz.rlib
+
+# - rmeta file added to rlib, no object files are generated and thus no debuginfo is generated
+# - `.o` never created
+# - `.dwo` never created
+# - `.dwp` never created
+packed-lto-single:
+	$(RUSTC) baz.rs -g $(UNSTABLEOPTS) -Csplit-debuginfo=packed -Zsplit-dwarf-kind=single \
+		--crate-type=rlib -Clinker-plugin-lto
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
 	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
-	rm -rf $(TMPDIR)/*.dwp
+	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
+	rm $(TMPDIR)/libbaz.rlib
 
 packed-remapped: packed-remapped-split packed-remapped-single
 
+# - Debuginfo in `.dwo` files
+# - `.o` and binary refer to remapped `.dwo` paths which do not exist
+# - `.o` deleted
+# - `.dwo` deleted
+# - `.dwp` present
 packed-remapped-split:
 	$(RUSTC) $(UNSTABLEOPTS) -C split-debuginfo=packed -C debuginfo=2 \
 		-Z split-dwarf-kind=split --remap-path-prefix $(TMPDIR)=/a foo.rs -g
 	objdump -Wi $(TMPDIR)/foo | grep DW_AT_GNU_dwo_name | (! grep $(TMPDIR)) || exit 1
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
+	rm $(TMPDIR)/foo.dwp
+	rm $(TMPDIR)/$(call BIN,foo)
 
+# - Debuginfo in `.o` files
+# - `.o` and binary refer to remapped `.o` paths which do not exist
+# - `.o` deleted
+# - `.dwo` never created
+# - `.dwp` present
 packed-remapped-single:
 	$(RUSTC) $(UNSTABLEOPTS) -C split-debuginfo=packed -C debuginfo=2 \
 		-Z split-dwarf-kind=single --remap-path-prefix $(TMPDIR)=/a foo.rs -g
 	objdump -Wi $(TMPDIR)/foo | grep DW_AT_GNU_dwo_name | (! grep $(TMPDIR)) || exit 1
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
+	rm $(TMPDIR)/foo.dwp
+	rm $(TMPDIR)/$(call BIN,foo)
 
 packed-crosscrate: packed-crosscrate-split packed-crosscrate-single
 
+# - Debuginfo in `.dwo` files
+# - (bar) `.rlib` file created, contains `.dwo`
+# - (bar) `.o` deleted
+# - (bar) `.dwo` deleted
+# - (bar) `.dwp` never created
+# - (main) `.o` deleted
+# - (main) `.dwo` deleted
+# - (main) `.dwp` present
 packed-crosscrate-split:
 	$(RUSTC) --crate-type lib $(UNSTABLEOPTS) -C split-debuginfo=packed \
 		-Zsplit-dwarf-kind=split -C debuginfo=2 -g bar.rs
 	ls $(TMPDIR)/*.rlib
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
 	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
 	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
-	$(RUSTC) --extern bar=$(TMPDIR)/libbar.rlib -Z unstable-options $(UNSTABLEOPTS) \
+	$(RUSTC) --extern bar=$(TMPDIR)/libbar.rlib $(UNSTABLEOPTS) \
 		-C split-debuginfo=packed -Zsplit-dwarf-kind=split -C debuginfo=2 -g main.rs
-	rm $(TMPDIR)/*.dwo
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
 	rm $(TMPDIR)/main.dwp
 	rm $(TMPDIR)/$(call BIN,main)
 
+# - Debuginfo in `.o` files
+# - (bar) `.rlib` file created, contains `.o`
+# - (bar) `.o` deleted
+# - (bar) `.dwo` never created
+# - (bar) `.dwp` never created
+# - (main) `.o` deleted
+# - (main) `.dwo` never created
+# - (main) `.dwp` present
 packed-crosscrate-single:
 	$(RUSTC) --crate-type lib $(UNSTABLEOPTS) -C split-debuginfo=packed \
 		-Zsplit-dwarf-kind=single -C debuginfo=2 -g bar.rs
 	ls $(TMPDIR)/*.rlib
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
 	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
 	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
-	$(RUSTC) --extern bar=$(TMPDIR)/libbar.rlib -Z unstable-options $(UNSTABLEOPTS) \
+	$(RUSTC) --extern bar=$(TMPDIR)/libbar.rlib $(UNSTABLEOPTS) \
 		-C split-debuginfo=packed -Zsplit-dwarf-kind=single -C debuginfo=2 -g main.rs
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
 	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
 	rm $(TMPDIR)/main.dwp
 	rm $(TMPDIR)/$(call BIN,main)
 
-unpacked: unpacked-split unpacked-single unpacked-remapped-split unpacked-remapped-single
+unpacked: unpacked-split unpacked-single unpacked-lto unpacked-remapped unpacked-crosscrate
 
+# - Debuginfo in `.dwo` files
+# - `.o` deleted
+# - `.dwo` present
+# - `.dwp` never created
 unpacked-split:
 	$(RUSTC) foo.rs -g $(UNSTABLEOPTS) -C split-debuginfo=unpacked -Zsplit-dwarf-kind=split
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
+	rm $(TMPDIR)/*.dwo
 	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
-	ls $(TMPDIR)/*.dwo
-	rm -rf $(TMPDIR)/*.dwp $(TMPDIR)/*.dwo
+	rm $(TMPDIR)/$(call BIN,foo)
 
+# - Debuginfo in `.o` files
+# - `.o` present
+# - `.dwo` never created
+# - `.dwp` never created
 unpacked-single:
 	$(RUSTC) foo.rs -g $(UNSTABLEOPTS) -C split-debuginfo=unpacked -Zsplit-dwarf-kind=single
+	ls $(TMPDIR)/*.o
+	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
+	rm $(TMPDIR)/$(call BIN,foo)
+
+unpacked-lto: packed-lto-split packed-lto-single
+
+# - rmeta file added to rlib, no object files are generated and thus no debuginfo is generated
+# - `.o` never created
+# - `.dwo` never created
+# - `.dwp` never created
+unpacked-lto-split:
+	$(RUSTC) baz.rs -g $(UNSTABLEOPTS) -Csplit-debuginfo=unpacked -Zsplit-dwarf-kind=split \
+		--crate-type=rlib -Clinker-plugin-lto
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
 	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
+	rm $(TMPDIR)/libbaz.rlib
+
+# - rmeta file added to rlib, no object files are generated and thus no debuginfo is generated
+# - `.o` never created
+# - `.dwo` never created
+# - `.dwp` never created
+unpacked-lto-single:
+	$(RUSTC) baz.rs -g $(UNSTABLEOPTS) -Csplit-debuginfo=unpacked -Zsplit-dwarf-kind=single \
+		--crate-type=rlib -Clinker-plugin-lto
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
 	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
+	rm $(TMPDIR)/libbaz.rlib
+
+unpacked-remapped: unpacked-remapped-split unpacked-remapped-single
 
+# - Debuginfo in `.dwo` files
+# - `.o` and binary refer to remapped `.dwo` paths which do not exist
+# - `.o` deleted
+# - `.dwo` present
+# - `.dwp` never created
 unpacked-remapped-split:
 	$(RUSTC) $(UNSTABLEOPTS) -C split-debuginfo=unpacked -C debuginfo=2 \
 		-Z split-dwarf-kind=split --remap-path-prefix $(TMPDIR)=/a foo.rs -g
 	objdump -Wi $(TMPDIR)/foo | grep DW_AT_GNU_dwo_name | (! grep $(TMPDIR)) || exit 1
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
+	rm $(TMPDIR)/*.dwo
+	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
+	rm $(TMPDIR)/$(call BIN,foo)
 
+# - Debuginfo in `.o` files
+# - `.o` and binary refer to remapped `.o` paths which do not exist
+# - `.o` present
+# - `.dwo` never created
+# - `.dwp` never created
 unpacked-remapped-single:
 	$(RUSTC) $(UNSTABLEOPTS) -C split-debuginfo=unpacked -C debuginfo=2 \
 		-Z split-dwarf-kind=single --remap-path-prefix $(TMPDIR)=/a foo.rs -g
 	objdump -Wi $(TMPDIR)/foo | grep DW_AT_GNU_dwo_name | (! grep $(TMPDIR)) || exit 1
+	ls $(TMPDIR)/*.o
+	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
+	rm $(TMPDIR)/$(call BIN,foo)
+
+unpacked-crosscrate: packed-crosscrate-split packed-crosscrate-single
+
+# - Debuginfo in `.dwo` files
+# - (bar) `.rlib` file created, contains `.dwo`
+# - (bar) `.o` deleted
+# - (bar) `.dwo` present
+# - (bar) `.dwp` never created
+# - (main) `.o` deleted
+# - (main) `.dwo` present
+# - (main) `.dwp` never created
+unpacked-crosscrate-split:
+	$(RUSTC) --crate-type lib $(UNSTABLEOPTS) -C split-debuginfo=unpacked \
+		-Zsplit-dwarf-kind=split -C debuginfo=2 -g bar.rs
+	ls $(TMPDIR)/*.rlib
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwo
+	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
+	$(RUSTC) --extern bar=$(TMPDIR)/libbar.rlib $(UNSTABLEOPTS) \
+		-C split-debuginfo=unpacked -Zsplit-dwarf-kind=split -C debuginfo=2 -g main.rs
+	ls $(TMPDIR)/*.o && exit 1 || exit 0
+	rm $(TMPDIR)/*.dwo
+	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
+	rm $(TMPDIR)/$(call BIN,main)
+
+# - Debuginfo in `.o` files
+# - (bar) `.rlib` file created, contains `.o`
+# - (bar) `.o` present
+# - (bar) `.dwo` never created
+# - (bar) `.dwp` never created
+# - (main) `.o` present
+# - (main) `.dwo` never created
+# - (main) `.dwp` never created
+unpacked-crosscrate-single:
+	$(RUSTC) --crate-type lib $(UNSTABLEOPTS) -C split-debuginfo=unpacked \
+		-Zsplit-dwarf-kind=single -C debuginfo=2 -g bar.rs
+	ls $(TMPDIR)/*.rlib
+	ls $(TMPDIR)/*.o
+	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
+	$(RUSTC) --extern bar=$(TMPDIR)/libbar.rlib $(UNSTABLEOPTS) \
+		-C split-debuginfo=unpacked -Zsplit-dwarf-kind=single -C debuginfo=2 -g main.rs
+	ls $(TMPDIR)/*.o
+	ls $(TMPDIR)/*.dwo && exit 1 || exit 0
+	ls $(TMPDIR)/*.dwp && exit 1 || exit 0
+	rm $(TMPDIR)/$(call BIN,main)
 endif
 endif
diff --git a/src/test/run-make-fulldeps/split-debuginfo/baz.rs b/src/test/run-make-fulldeps/split-debuginfo/baz.rs
new file mode 100644
index 0000000000000..8b1a393741c96
--- /dev/null
+++ b/src/test/run-make-fulldeps/split-debuginfo/baz.rs
@@ -0,0 +1 @@
+// empty
diff --git a/src/test/ui/borrowck/async-reference-generality.rs b/src/test/ui/borrowck/async-reference-generality.rs
new file mode 100644
index 0000000000000..487d1ac81bfc6
--- /dev/null
+++ b/src/test/ui/borrowck/async-reference-generality.rs
@@ -0,0 +1,35 @@
+// check-fail
+// known-bug: #99492
+// edition: 2021
+
+use std::marker::PhantomData;
+
+pub struct Struct<I, T>(PhantomData<fn() -> <Self as It>::Item>)
+where
+    Self: It;
+
+impl<I> It for Struct<I, I::Item>
+where
+    I: It,
+{
+    type Item = ();
+}
+
+pub trait It {
+    type Item;
+}
+
+fn f() -> impl Send {
+    async {
+        let _x = Struct::<Empty<&'static ()>, _>(PhantomData);
+        async {}.await;
+    }
+}
+
+pub struct Empty<T>(PhantomData<fn() -> T>);
+
+impl<T> It for Empty<T> {
+    type Item = T;
+}
+
+fn main() {}
diff --git a/src/test/ui/borrowck/async-reference-generality.stderr b/src/test/ui/borrowck/async-reference-generality.stderr
new file mode 100644
index 0000000000000..af720ad29314f
--- /dev/null
+++ b/src/test/ui/borrowck/async-reference-generality.stderr
@@ -0,0 +1,27 @@
+error[E0308]: mismatched types
+  --> $DIR/async-reference-generality.rs:23:5
+   |
+LL | /     async {
+LL | |         let _x = Struct::<Empty<&'static ()>, _>(PhantomData);
+LL | |         async {}.await;
+LL | |     }
+   | |_____^ one type is more general than the other
+   |
+   = note: expected reference `&()`
+              found reference `&()`
+
+error[E0308]: mismatched types
+  --> $DIR/async-reference-generality.rs:23:5
+   |
+LL | /     async {
+LL | |         let _x = Struct::<Empty<&'static ()>, _>(PhantomData);
+LL | |         async {}.await;
+LL | |     }
+   | |_____^ one type is more general than the other
+   |
+   = note: expected reference `&()`
+              found reference `&()`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/dyn-star/issue-102430.rs b/src/test/ui/dyn-star/issue-102430.rs
new file mode 100644
index 0000000000000..244ecda6626ae
--- /dev/null
+++ b/src/test/ui/dyn-star/issue-102430.rs
@@ -0,0 +1,32 @@
+// check-pass
+
+#![feature(dyn_star)]
+#![allow(incomplete_features)]
+
+trait AddOne {
+    fn add1(&mut self) -> usize;
+}
+
+impl AddOne for usize {
+    fn add1(&mut self) -> usize {
+        *self += 1;
+        *self
+    }
+}
+
+impl AddOne for &mut usize {
+    fn add1(&mut self) -> usize {
+        (*self).add1()
+    }
+}
+
+fn add_one(mut i: dyn* AddOne + '_) -> usize {
+    i.add1()
+}
+
+fn main() {
+    let mut x = 42usize;
+    let y = &mut x as (dyn* AddOne + '_);
+
+    println!("{}", add_one(y));
+}
diff --git a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90950.rs b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90950.rs
new file mode 100644
index 0000000000000..ab9d9a7ce6f08
--- /dev/null
+++ b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90950.rs
@@ -0,0 +1,53 @@
+// check-fail
+// known-bug: #90950
+
+trait Yokeable<'a>: 'static {
+    type Output: 'a;
+}
+
+
+trait IsCovariant<'a> {}
+
+struct Yoke<Y: for<'a> Yokeable<'a>> {
+    data: Y,
+}
+
+
+// impl<Y: for<'a> Yokeable<'a>> Yoke<Y> {
+//     fn project<Y2: for<'a> Yokeable<'a>>(
+//         &self,
+//         f: for<'a> fn(<Y as Yokeable<'a>>::Output, &'a (),
+//     ) -> <Y2 as Yokeable<'a>>::Output) -> Yoke<Y2> {
+//         unimplemented!()
+//     }
+// }
+
+fn upcast<Y>(x: Yoke<Y>) -> Yoke<Box<dyn IsCovariant<'static> + 'static>> where
+    Y: for<'a> Yokeable<'a>,
+    for<'a> <Y as Yokeable<'a>>::Output: IsCovariant<'a>
+    {
+    // x.project(|data, _| {
+    //     Box::new(data)
+    // })
+    unimplemented!()
+}
+
+
+impl<'a> Yokeable<'a> for Box<dyn IsCovariant<'static> + 'static> {
+    type Output = Box<dyn IsCovariant<'a> + 'a>;
+}
+
+// this impl is mostly an example and unnecessary for the pure repro
+use std::borrow::*;
+impl<'a, T: ToOwned + ?Sized> Yokeable<'a> for Cow<'static, T> {
+    type Output = Cow<'a, T>;
+}
+impl<'a, T: ToOwned + ?Sized> IsCovariant<'a> for Cow<'a, T> {}
+
+
+
+fn upcast_yoke(y: Yoke<Cow<'static, str>>) -> Yoke<Box<dyn IsCovariant<'static> + 'static>> {
+    upcast(y)
+}
+
+fn main() {}
diff --git a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90950.stderr b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90950.stderr
new file mode 100644
index 0000000000000..6206b167b0b8d
--- /dev/null
+++ b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-90950.stderr
@@ -0,0 +1,21 @@
+error[E0277]: the trait bound `for<'a> <_ as Yokeable<'a>>::Output: IsCovariant<'a>` is not satisfied
+  --> $DIR/issue-90950.rs:50:12
+   |
+LL |     upcast(y)
+   |     ------ ^ the trait `for<'a> IsCovariant<'a>` is not implemented for `<_ as Yokeable<'a>>::Output`
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = help: the trait `IsCovariant<'a>` is implemented for `std::borrow::Cow<'a, T>`
+note: required by a bound in `upcast`
+  --> $DIR/issue-90950.rs:27:42
+   |
+LL | fn upcast<Y>(x: Yoke<Y>) -> Yoke<Box<dyn IsCovariant<'static> + 'static>> where
+   |    ------ required by a bound in this
+LL |     Y: for<'a> Yokeable<'a>,
+LL |     for<'a> <Y as Yokeable<'a>>::Output: IsCovariant<'a>
+   |                                          ^^^^^^^^^^^^^^^ required by this bound in `upcast`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/norm-before-method-resolution.rs b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/norm-before-method-resolution.rs
new file mode 100644
index 0000000000000..7693b11824762
--- /dev/null
+++ b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/norm-before-method-resolution.rs
@@ -0,0 +1,23 @@
+// check-fail
+// known-bug: #89196
+
+// Should pass, but we normalize and check bounds before we resolve the generics
+// of the function (which we know because of the return type).
+
+trait Trait<'a> {
+    type Out;
+}
+
+impl<'a, T> Trait<'a> for T {
+    type Out = T;
+}
+
+fn weird_bound<X>() -> X
+    where
+        for<'a> X: Trait<'a>,
+        for<'a> <X as Trait<'a>>::Out: Copy
+{ todo!() }
+
+fn main() {
+    let _: () = weird_bound();
+}
diff --git a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/norm-before-method-resolution.stderr b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/norm-before-method-resolution.stderr
new file mode 100644
index 0000000000000..51c9646004afa
--- /dev/null
+++ b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/norm-before-method-resolution.stderr
@@ -0,0 +1,18 @@
+error[E0277]: the trait bound `for<'a> <_ as Trait<'a>>::Out: Copy` is not satisfied
+  --> $DIR/norm-before-method-resolution.rs:22:17
+   |
+LL |     let _: () = weird_bound();
+   |                 ^^^^^^^^^^^ the trait `for<'a> Copy` is not implemented for `<_ as Trait<'a>>::Out`
+   |
+note: required by a bound in `weird_bound`
+  --> $DIR/norm-before-method-resolution.rs:18:40
+   |
+LL | fn weird_bound<X>() -> X
+   |    ----------- required by a bound in this
+...
+LL |         for<'a> <X as Trait<'a>>::Out: Copy
+   |                                        ^^^^ required by this bound in `weird_bound`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/never_type/exhaustive_patterns.rs b/src/test/ui/never_type/exhaustive_patterns.rs
new file mode 100644
index 0000000000000..2e23fa1828091
--- /dev/null
+++ b/src/test/ui/never_type/exhaustive_patterns.rs
@@ -0,0 +1,21 @@
+// check-fail
+// known-bug: #104034
+
+#![feature(exhaustive_patterns, never_type)]
+
+mod inner {
+    pub struct Wrapper<T>(T);
+}
+
+enum Either<A, B> {
+    A(A),
+    B(inner::Wrapper<B>),
+}
+
+fn foo() -> Either<(), !> {
+    Either::A(())
+}
+
+fn main() {
+    let Either::A(()) = foo();
+}
diff --git a/src/test/ui/never_type/exhaustive_patterns.stderr b/src/test/ui/never_type/exhaustive_patterns.stderr
new file mode 100644
index 0000000000000..e41baf862180d
--- /dev/null
+++ b/src/test/ui/never_type/exhaustive_patterns.stderr
@@ -0,0 +1,25 @@
+error[E0005]: refutable pattern in local binding: `Either::B(_)` not covered
+  --> $DIR/exhaustive_patterns.rs:20:9
+   |
+LL |     let Either::A(()) = foo();
+   |         ^^^^^^^^^^^^^ pattern `Either::B(_)` not covered
+   |
+   = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
+   = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
+note: `Either<(), !>` defined here
+  --> $DIR/exhaustive_patterns.rs:12:5
+   |
+LL | enum Either<A, B> {
+   |      ------
+LL |     A(A),
+LL |     B(inner::Wrapper<B>),
+   |     ^ not covered
+   = note: the matched value is of type `Either<(), !>`
+help: you might want to use `if let` to ignore the variant that isn't matched
+   |
+LL |     if let Either::A(()) = foo() { todo!() }
+   |     ++                           ~~~~~~~~~~~
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0005`.
diff --git a/src/test/ui/nll/user-annotations/ascribed-type-wf.rs b/src/test/ui/nll/user-annotations/ascribed-type-wf.rs
new file mode 100644
index 0000000000000..14460dea5b527
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/ascribed-type-wf.rs
@@ -0,0 +1,16 @@
+// check-pass
+// known-bug: #101350
+
+trait Trait {
+    type Ty;
+}
+
+impl Trait for &'static () {
+    type Ty = ();
+}
+
+fn extend<'a>() {
+    None::<<&'a () as Trait>::Ty>;
+}
+
+fn main() {}
diff --git a/src/test/ui/traits/suggest-fully-qualified-closure.rs b/src/test/ui/traits/suggest-fully-qualified-closure.rs
new file mode 100644
index 0000000000000..c077921c0bdd2
--- /dev/null
+++ b/src/test/ui/traits/suggest-fully-qualified-closure.rs
@@ -0,0 +1,24 @@
+// check-fail
+// known-bug: #103705
+// normalize-stderr-test "\[closure@.*\]" -> "[closure@]"
+// normalize-stderr-test "\+* ~" -> "+++ ~"
+
+// The output of this currently suggests writing a closure in the qualified path.
+
+trait MyTrait<T> {
+   fn lol<F:FnOnce()>(&self, f:F) -> u16;
+}
+
+struct Qqq;
+
+impl MyTrait<u32> for Qqq{
+   fn lol<F:FnOnce()>(&self, _f:F) -> u16 { 5 }
+}
+impl MyTrait<u64> for Qqq{
+   fn lol<F:FnOnce()>(&self, _f:F) -> u16 { 6 }
+}
+
+fn main() {
+    let q = Qqq;
+    q.lol(||());
+}
diff --git a/src/test/ui/traits/suggest-fully-qualified-closure.stderr b/src/test/ui/traits/suggest-fully-qualified-closure.stderr
new file mode 100644
index 0000000000000..3df623c14c3d6
--- /dev/null
+++ b/src/test/ui/traits/suggest-fully-qualified-closure.stderr
@@ -0,0 +1,34 @@
+error[E0282]: type annotations needed
+  --> $DIR/suggest-fully-qualified-closure.rs:23:7
+   |
+LL |     q.lol(||());
+   |       ^^^
+   |
+help: try using a fully qualified path to specify the expected types
+   |
+LL |     <Qqq as MyTrait<T>>::lol::<[closure@]>(&q, ||());
+   |     +++ ~
+
+error[E0283]: type annotations needed
+  --> $DIR/suggest-fully-qualified-closure.rs:23:7
+   |
+LL |     q.lol(||());
+   |       ^^^
+   |
+note: multiple `impl`s satisfying `Qqq: MyTrait<_>` found
+  --> $DIR/suggest-fully-qualified-closure.rs:14:1
+   |
+LL | impl MyTrait<u32> for Qqq{
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL | impl MyTrait<u64> for Qqq{
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+help: try using a fully qualified path to specify the expected types
+   |
+LL |     <Qqq as MyTrait<T>>::lol::<[closure@]>(&q, ||());
+   |     +++ ~
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0282, E0283.
+For more information about an error, try `rustc --explain E0282`.
diff --git a/src/test/ui/typeck/issue-103899.rs b/src/test/ui/typeck/issue-103899.rs
new file mode 100644
index 0000000000000..9d5341dab42f3
--- /dev/null
+++ b/src/test/ui/typeck/issue-103899.rs
@@ -0,0 +1,33 @@
+// check-fail
+// failure-status: 101
+// normalize-stderr-test "note: .*" -> ""
+// normalize-stderr-test "thread 'rustc' .*" -> ""
+// normalize-stderr-test " .*\n" -> ""
+// normalize-stderr-test "  .*\n" -> ""
+// known-bug: #103899
+
+trait BaseWithAssoc {
+    type Assoc;
+}
+
+trait WrapperWithAssoc {
+    type BaseAssoc: BaseWithAssoc;
+}
+
+struct Wrapper<B> {
+    inner: B,
+}
+
+struct ProjectToBase<T: BaseWithAssoc> {
+    data_type_h: T::Assoc,
+}
+
+struct DoubleProject<L: WrapperWithAssoc> {
+    buffer: Wrapper<ProjectToBase<L::BaseAssoc>>,
+}
+
+fn trigger<L: WrapperWithAssoc<BaseAssoc = ()>>() -> DoubleProject<L> {
+    loop {}
+}
+
+fn main() {}
diff --git a/src/test/ui/typeck/issue-103899.stderr b/src/test/ui/typeck/issue-103899.stderr
new file mode 100644
index 0000000000000..836c6ee486f51
--- /dev/null
+++ b/src/test/ui/typeck/issue-103899.stderr
@@ -0,0 +1,12 @@
+
+stack
+error:
+
+
+
+
+
+
+
+
+query#0#1end
\ No newline at end of file