Auto merge of #79441 - jonas-schievink:rollup-l9v00bl, r=jonas-schievink

Rollup of 10 pull requests

Successful merges:

 - #77758 (suggest turbofish syntax for uninferred const arguments)
 - #79000 (Move lev_distance to rustc_ast, make non-generic)
 - #79362 (Lower patterns before using the bound variable)
 - #79365 (Upgrades the coverage map to Version 4)
 - #79402 (Fix typos)
 - #79412 (Clean up rustdoc tests by removing unnecessary features)
 - #79413 (Fix persisted doctests on Windows / when using workspaces)
 - #79420 (Fixes a word typo in librustdoc)
 - #79421 (Fix docs formatting for `thir::pattern::_match`)
 - #79428 (Fixup compiler docs)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

31 files changed, 138 insertions, 42 deletions

diff --git a/src/test/run-make-fulldeps/coverage-llvmir-base/Makefile b/src/test/run-make-fulldeps/coverage-llvmir-base/Makefile
index e84642922d9..219ba15ad11 100644
--- a/src/test/run-make-fulldeps/coverage-llvmir-base/Makefile
+++ b/src/test/run-make-fulldeps/coverage-llvmir-base/Makefile
@@ -12,10 +12,12 @@ ifeq ($(UNAME),Darwin)
 	INSTR_PROF_DATA_SUFFIX=,regular,live_support
 	DATA_SECTION_PREFIX=__DATA,
 	LLVM_COV_SECTION_PREFIX=__LLVM_COV,
+	COMDAT_IF_SUPPORTED=
 else
 	INSTR_PROF_DATA_SUFFIX=
 	DATA_SECTION_PREFIX=
 	LLVM_COV_SECTION_PREFIX=
+	COMDAT_IF_SUPPORTED=, comdat
 endif
 
 ifeq ($(LINK_DEAD_CODE),yes)
@@ -29,28 +31,39 @@ ifdef IS_WINDOWS
 		-check-prefixes=CHECK,WINDOWS \
 		-DPRIVATE_GLOBAL='internal global' \
 		-DDEFINE_INTERNAL='$(DEFINE_INTERNAL)' \
+		-DCOMDAT_IF_SUPPORTED='$(COMDAT_IF_SUPPORTED)' \
 		-DINSTR_PROF_DATA='.lprfd$$M' \
 		-DINSTR_PROF_NAME='.lprfn$$M' \
 		-DINSTR_PROF_CNTS='.lprfc$$M' \
 		-DINSTR_PROF_VALS='.lprfv$$M' \
 		-DINSTR_PROF_VNODES='.lprfnd$$M' \
 		-DINSTR_PROF_COVMAP='.lcovmap$$M' \
+		-DINSTR_PROF_COVFUN='.lcovfun$$M' \
 		-DINSTR_PROF_ORDERFILE='.lorderfile$$M'
 else
 	LLVM_FILECHECK_OPTIONS=\
 		-check-prefixes=CHECK \
 		-DPRIVATE_GLOBAL='private global' \
 		-DDEFINE_INTERNAL='$(DEFINE_INTERNAL)' \
+		-DCOMDAT_IF_SUPPORTED='$(COMDAT_IF_SUPPORTED)' \
 		-DINSTR_PROF_DATA='$(DATA_SECTION_PREFIX)__llvm_prf_data$(INSTR_PROF_DATA_SUFFIX)' \
 		-DINSTR_PROF_NAME='$(DATA_SECTION_PREFIX)__llvm_prf_names' \
 		-DINSTR_PROF_CNTS='$(DATA_SECTION_PREFIX)__llvm_prf_cnts' \
 		-DINSTR_PROF_VALS='$(DATA_SECTION_PREFIX)__llvm_prf_vals' \
 		-DINSTR_PROF_VNODES='$(DATA_SECTION_PREFIX)__llvm_prf_vnds' \
 		-DINSTR_PROF_COVMAP='$(LLVM_COV_SECTION_PREFIX)__llvm_covmap' \
+		-DINSTR_PROF_COVFUN='$(LLVM_COV_SECTION_PREFIX)__llvm_covfun' \
 		-DINSTR_PROF_ORDERFILE='$(DATA_SECTION_PREFIX)__llvm_orderfile'
 endif
 
+ifeq ($(LLVM_VERSION_11_PLUS),true)
+all: test_llvm_ir
+else
+$(info Rust option `-Z instrument-coverage` requires LLVM 11 or higher. Test skipped.)
 all:
+endif
+
+test_llvm_ir:
 	# Compile the test program with non-experimental coverage instrumentation, and generate LLVM IR
 	#
 	# Note: `-Clink-dead-code=no` disables the option, needed because the option is automatically
@@ -62,4 +75,5 @@ all:
 			-Clink-dead-code=$(LINK_DEAD_CODE) \
 			--emit=llvm-ir
 
-	cat "$(TMPDIR)"/testprog.ll | "$(LLVM_FILECHECK)" $(BASEDIR)/filecheck.testprog.txt $(LLVM_FILECHECK_OPTIONS)
+	cat "$(TMPDIR)"/testprog.ll | \
+			"$(LLVM_FILECHECK)" $(BASEDIR)/filecheck.testprog.txt $(LLVM_FILECHECK_OPTIONS)
diff --git a/src/test/run-make-fulldeps/coverage-llvmir-base/filecheck.testprog.txt b/src/test/run-make-fulldeps/coverage-llvmir-base/filecheck.testprog.txt
index bd2a2475d9e..a312ec48e84 100644
--- a/src/test/run-make-fulldeps/coverage-llvmir-base/filecheck.testprog.txt
+++ b/src/test/run-make-fulldeps/coverage-llvmir-base/filecheck.testprog.txt
@@ -3,7 +3,10 @@
 
 WINDOWS:      $__llvm_profile_runtime_user = comdat any
 
-CHECK:        @__llvm_coverage_mapping = internal constant
+CHECK:        @__covrec_{{[A-F0-9]+}}u = linkonce_odr hidden constant
+CHECK-SAME:   section "[[INSTR_PROF_COVFUN]]"[[COMDAT_IF_SUPPORTED]], align 8
+
+CHECK:        @__llvm_coverage_mapping = private constant
 CHECK-SAME:   section "[[INSTR_PROF_COVMAP]]", align 8
 
 WINDOWS:      @__llvm_profile_runtime = external global i32
diff --git a/src/test/run-make-fulldeps/coverage-reports-base/Makefile b/src/test/run-make-fulldeps/coverage-reports-base/Makefile
index 1e2aa056e40..2dac8fc2225 100644
--- a/src/test/run-make-fulldeps/coverage-reports-base/Makefile
+++ b/src/test/run-make-fulldeps/coverage-reports-base/Makefile
@@ -18,7 +18,10 @@ SOURCEDIR=../coverage
 # `llvm/release_debuginfo`. Note that some CI builds disable debug assertions (by setting
 # `NO_LLVM_ASSERTIONS=1`), so it is not OK to fail the test, but `bless`ed test results cannot be
 # generated without debug assertions.
-LLVM_COV_DEBUG := $(shell "$(LLVM_BIN_DIR)"/llvm-cov show --debug 2>&1 | grep -q "Unknown command line argument '--debug'"; echo $$?)
+LLVM_COV_DEBUG := $(shell \
+		"$(LLVM_BIN_DIR)"/llvm-cov show --debug 2>&1 | \
+		grep -q "Unknown command line argument '--debug'"; \
+		echo $$?)
 ifeq ($(LLVM_COV_DEBUG), 1)
 DEBUG_FLAG=--debug
 endif
@@ -30,7 +33,12 @@ ifdef RUSTC_BLESS_TEST
 DEBUG_FLAG=--debug
 endif
 
+ifeq ($(LLVM_VERSION_11_PLUS),true)
 all: $(patsubst $(SOURCEDIR)/%.rs,%,$(wildcard $(SOURCEDIR)/*.rs))
+else
+$(info Rust option `-Z instrument-coverage` requires LLVM 11 or higher. Test skipped.)
+all:
+endif
 
 # Ensure there are no `expected` results for tests that may have been removed or renamed
 .PHONY: clear_expected_if_blessed
diff --git a/src/test/run-make-fulldeps/coverage-spanview-base/Makefile b/src/test/run-make-fulldeps/coverage-spanview-base/Makefile
index 03ef04776a0..9f9440340e0 100644
--- a/src/test/run-make-fulldeps/coverage-spanview-base/Makefile
+++ b/src/test/run-make-fulldeps/coverage-spanview-base/Makefile
@@ -24,7 +24,12 @@ For revisions in Pull Requests (PR):
 endef
 export SPANVIEW_HEADER
 
+ifeq ($(LLVM_VERSION_11_PLUS),true)
 all: $(patsubst $(SOURCEDIR)/%.rs,%,$(wildcard $(SOURCEDIR)/*.rs))
+else
+$(info Rust option `-Z instrument-coverage` requires LLVM 11 or higher. Test skipped.)
+all:
+endif
 
 # Ensure there are no `expected` results for tests that may have been removed or renamed
 .PHONY: clear_expected_if_blessed
diff --git a/src/test/run-make-fulldeps/coverage/coverage_tools.mk b/src/test/run-make-fulldeps/coverage/coverage_tools.mk
index 17f7696a8cf..99a2e0ba952 100644
--- a/src/test/run-make-fulldeps/coverage/coverage_tools.mk
+++ b/src/test/run-make-fulldeps/coverage/coverage_tools.mk
@@ -38,6 +38,13 @@ endif
 
 UNAME = $(shell uname)
 
+# Rust option `-Z instrument-coverage` uses LLVM Coverage Mapping Format version 4,
+# which requires LLVM 11 or greater.
+LLVM_VERSION_11_PLUS := $(shell \
+		LLVM_VERSION=$$("$(LLVM_BIN_DIR)"/llvm-config --version) && \
+		LLVM_VERSION_MAJOR=$${LLVM_VERSION/.*/} && \
+		[ $$LLVM_VERSION_MAJOR -ge 11 ] && echo true || echo false)
+
 # FIXME(richkadel): Can any of the features tested by `run-make-fulldeps/coverage-*` tests be tested
 # just as completely by more focused unit tests of the code logic itself, to reduce the number of
 # test result files generated and maintained, and to help identify specific test failures and root
diff --git a/src/test/rustdoc-js/doc-alias-filter-out.rs b/src/test/rustdoc-js/doc-alias-filter-out.rs
index 815e8cedd16..3f0c094794e 100644
--- a/src/test/rustdoc-js/doc-alias-filter-out.rs
+++ b/src/test/rustdoc-js/doc-alias-filter-out.rs
@@ -1,4 +1,2 @@
-#![feature(doc_alias)]
-
 #[doc(alias = "true")]
 pub struct Foo;
diff --git a/src/test/rustdoc-js/doc-alias-filter.rs b/src/test/rustdoc-js/doc-alias-filter.rs
index 8887f8c2b01..d5227814c06 100644
--- a/src/test/rustdoc-js/doc-alias-filter.rs
+++ b/src/test/rustdoc-js/doc-alias-filter.rs
@@ -1,5 +1,3 @@
-#![feature(doc_alias)]
-
 #[doc(alias = "true")]
 pub struct Foo;
 
diff --git a/src/test/rustdoc-js/doc-alias-whitespace.rs b/src/test/rustdoc-js/doc-alias-whitespace.rs
index bea3e382ae4..16c022c7498 100644
--- a/src/test/rustdoc-js/doc-alias-whitespace.rs
+++ b/src/test/rustdoc-js/doc-alias-whitespace.rs
@@ -1,4 +1,2 @@
-#![feature(doc_alias)]
-
 #[doc(alias = "Demon Lord")]
 pub struct Struct;
diff --git a/src/test/rustdoc-js/doc-alias.rs b/src/test/rustdoc-js/doc-alias.rs
index 41caa98643c..750b7b757bc 100644
--- a/src/test/rustdoc-js/doc-alias.rs
+++ b/src/test/rustdoc-js/doc-alias.rs
@@ -1,5 +1,3 @@
-#![feature(doc_alias)]
-
 #[doc(alias = "StructItem")]
 pub struct Struct {
     #[doc(alias = "StructFieldItem")]
diff --git a/src/test/rustdoc-ui/check-doc-alias-attr-location.rs b/src/test/rustdoc-ui/check-doc-alias-attr-location.rs
index 545964c7bd6..7de2caa189d 100644
--- a/src/test/rustdoc-ui/check-doc-alias-attr-location.rs
+++ b/src/test/rustdoc-ui/check-doc-alias-attr-location.rs
@@ -1,5 +1,3 @@
-#![feature(doc_alias)]
-
 pub struct Bar;
 pub trait Foo {
     type X;
diff --git a/src/test/rustdoc-ui/check-doc-alias-attr-location.stderr b/src/test/rustdoc-ui/check-doc-alias-attr-location.stderr
index a66e9939eaf..175626f49dc 100644
--- a/src/test/rustdoc-ui/check-doc-alias-attr-location.stderr
+++ b/src/test/rustdoc-ui/check-doc-alias-attr-location.stderr
@@ -1,23 +1,23 @@
 error: `#[doc(alias = "...")]` isn't allowed on extern block
-  --> $DIR/check-doc-alias-attr-location.rs:9:7
+  --> $DIR/check-doc-alias-attr-location.rs:7:7
    |
 LL | #[doc(alias = "foo")]
    |       ^^^^^^^^^^^^^
 
 error: `#[doc(alias = "...")]` isn't allowed on implementation block
-  --> $DIR/check-doc-alias-attr-location.rs:12:7
+  --> $DIR/check-doc-alias-attr-location.rs:10:7
    |
 LL | #[doc(alias = "bar")]
    |       ^^^^^^^^^^^^^
 
 error: `#[doc(alias = "...")]` isn't allowed on implementation block
-  --> $DIR/check-doc-alias-attr-location.rs:18:7
+  --> $DIR/check-doc-alias-attr-location.rs:16:7
    |
 LL | #[doc(alias = "foobar")]
    |       ^^^^^^^^^^^^^^^^
 
 error: `#[doc(alias = "...")]` isn't allowed on type alias in implementation block
-  --> $DIR/check-doc-alias-attr-location.rs:20:11
+  --> $DIR/check-doc-alias-attr-location.rs:18:11
    |
 LL |     #[doc(alias = "assoc")]
    |           ^^^^^^^^^^^^^^^
diff --git a/src/test/rustdoc-ui/check-doc-alias-attr.rs b/src/test/rustdoc-ui/check-doc-alias-attr.rs
index 0ca2349a43b..912e35f9165 100644
--- a/src/test/rustdoc-ui/check-doc-alias-attr.rs
+++ b/src/test/rustdoc-ui/check-doc-alias-attr.rs
@@ -1,5 +1,4 @@
 #![crate_type = "lib"]
-#![feature(doc_alias)]
 
 #[doc(alias = "foo")] // ok!
 pub struct Bar;
diff --git a/src/test/rustdoc-ui/check-doc-alias-attr.stderr b/src/test/rustdoc-ui/check-doc-alias-attr.stderr
index 2c417a3bb65..8a729b02e72 100644
--- a/src/test/rustdoc-ui/check-doc-alias-attr.stderr
+++ b/src/test/rustdoc-ui/check-doc-alias-attr.stderr
@@ -1,35 +1,35 @@
 error: doc alias attribute expects a string: #[doc(alias = "0")]
-  --> $DIR/check-doc-alias-attr.rs:7:7
+  --> $DIR/check-doc-alias-attr.rs:6:7
    |
 LL | #[doc(alias)]
    |       ^^^^^
 
 error: doc alias attribute expects a string: #[doc(alias = "0")]
-  --> $DIR/check-doc-alias-attr.rs:8:7
+  --> $DIR/check-doc-alias-attr.rs:7:7
    |
 LL | #[doc(alias = 0)]
    |       ^^^^^^^^^
 
 error: doc alias attribute expects a string: #[doc(alias = "0")]
-  --> $DIR/check-doc-alias-attr.rs:9:7
+  --> $DIR/check-doc-alias-attr.rs:8:7
    |
 LL | #[doc(alias("bar"))]
    |       ^^^^^^^^^^^^
 
 error: '\"' character isn't allowed in `#[doc(alias = "...")]`
-  --> $DIR/check-doc-alias-attr.rs:10:7
+  --> $DIR/check-doc-alias-attr.rs:9:7
    |
 LL | #[doc(alias = "\"")]
    |       ^^^^^^^^^^^^
 
 error: '\n' character isn't allowed in `#[doc(alias = "...")]`
-  --> $DIR/check-doc-alias-attr.rs:11:7
+  --> $DIR/check-doc-alias-attr.rs:10:7
    |
 LL | #[doc(alias = "\n")]
    |       ^^^^^^^^^^^^
 
 error: '\n' character isn't allowed in `#[doc(alias = "...")]`
-  --> $DIR/check-doc-alias-attr.rs:12:7
+  --> $DIR/check-doc-alias-attr.rs:11:7
    |
 LL |   #[doc(alias = "
    |  _______^
@@ -37,19 +37,19 @@ LL | | ")]
    | |_^
 
 error: '\t' character isn't allowed in `#[doc(alias = "...")]`
-  --> $DIR/check-doc-alias-attr.rs:14:7
+  --> $DIR/check-doc-alias-attr.rs:13:7
    |
 LL | #[doc(alias = "\t")]
    |       ^^^^^^^^^^^^
 
 error: `#[doc(alias = "...")]` cannot start or end with ' '
-  --> $DIR/check-doc-alias-attr.rs:15:7
+  --> $DIR/check-doc-alias-attr.rs:14:7
    |
 LL | #[doc(alias = " hello")]
    |       ^^^^^^^^^^^^^^^^
 
 error: `#[doc(alias = "...")]` cannot start or end with ' '
-  --> $DIR/check-doc-alias-attr.rs:16:7
+  --> $DIR/check-doc-alias-attr.rs:15:7
    |
 LL | #[doc(alias = "hello ")]
    |       ^^^^^^^^^^^^^^^^
diff --git a/src/test/rustdoc-ui/doc-alias-assoc-const.rs b/src/test/rustdoc-ui/doc-alias-assoc-const.rs
index 73e23c152f2..d95324734be 100644
--- a/src/test/rustdoc-ui/doc-alias-assoc-const.rs
+++ b/src/test/rustdoc-ui/doc-alias-assoc-const.rs
@@ -1,4 +1,3 @@
-#![feature(doc_alias)]
 #![feature(trait_alias)]
 
 pub struct Foo;
diff --git a/src/test/rustdoc-ui/doc-alias-assoc-const.stderr b/src/test/rustdoc-ui/doc-alias-assoc-const.stderr
index 3c64548cc20..cbca40e1364 100644
--- a/src/test/rustdoc-ui/doc-alias-assoc-const.stderr
+++ b/src/test/rustdoc-ui/doc-alias-assoc-const.stderr
@@ -1,5 +1,5 @@
 error: `#[doc(alias = "...")]` isn't allowed on associated constant in trait implementation block
-  --> $DIR/doc-alias-assoc-const.rs:11:11
+  --> $DIR/doc-alias-assoc-const.rs:10:11
    |
 LL |     #[doc(alias = "CONST_BAZ")]
    |           ^^^^^^^^^^^^^^^^^^^
diff --git a/src/test/rustdoc-ui/doc-test-doctest-feature.rs b/src/test/rustdoc-ui/doc-test-doctest-feature.rs
index 9a79fb88383..2798804880a 100644
--- a/src/test/rustdoc-ui/doc-test-doctest-feature.rs
+++ b/src/test/rustdoc-ui/doc-test-doctest-feature.rs
@@ -2,13 +2,10 @@
 // compile-flags:--test
 // normalize-stdout-test: "src/test/rustdoc-ui" -> "$$DIR"
 
-#![feature(cfg_doctest)]
-
 // Make sure `cfg(doctest)` is set when finding doctests but not inside
 // the doctests.
 
 /// ```
-/// #![feature(cfg_doctest)]
 /// assert!(!cfg!(doctest));
 /// ```
 #[cfg(doctest)]
diff --git a/src/test/rustdoc-ui/doc-test-doctest-feature.stdout b/src/test/rustdoc-ui/doc-test-doctest-feature.stdout
index 75d29fab17d..b1cd74bf852 100644
--- a/src/test/rustdoc-ui/doc-test-doctest-feature.stdout
+++ b/src/test/rustdoc-ui/doc-test-doctest-feature.stdout
@@ -1,6 +1,6 @@
 
 running 1 test
-test $DIR/doc-test-doctest-feature.rs - Foo (line 10) ... ok
+test $DIR/doc-test-doctest-feature.rs - Foo (line 8) ... ok
 
 test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
 
diff --git a/src/test/rustdoc/deprecated-future.rs b/src/test/rustdoc/deprecated-future.rs
index c5248c52fb9..7db8cc60281 100644
--- a/src/test/rustdoc/deprecated-future.rs
+++ b/src/test/rustdoc/deprecated-future.rs
@@ -1,5 +1,3 @@
-#![feature(deprecated)]
-
 // @has deprecated_future/index.html '//*[@class="stab deprecated"]' \
 //      'Deprecated'
 // @has deprecated_future/struct.S.html '//*[@class="stab deprecated"]' \
diff --git a/src/test/rustdoc/deprecated.rs b/src/test/rustdoc/deprecated.rs
index 18a33438a23..a286856b2c3 100644
--- a/src/test/rustdoc/deprecated.rs
+++ b/src/test/rustdoc/deprecated.rs
@@ -1,5 +1,3 @@
-#![feature(deprecated)]
-
 // @has deprecated/index.html '//*[@class="docblock-short"]/span[@class="stab deprecated"]' \
 //      'Deprecated'
 // @has - '//*[@class="docblock-short"]' 'Deprecated docs'
diff --git a/src/test/rustdoc/issue-76501.rs b/src/test/rustdoc/issue-76501.rs
index 605059fe0dd..d468f35e280 100644
--- a/src/test/rustdoc/issue-76501.rs
+++ b/src/test/rustdoc/issue-76501.rs
@@ -1,5 +1,3 @@
-#![feature(const_fn)]
-
 // @has 'issue_76501/fn.bloop.html' '//pre' 'pub const fn bloop() -> i32'
 /// A useless function that always returns 1.
 pub const fn bloop() -> i32 {
diff --git a/src/test/ui/const-generics/infer/cannot-infer-const-args.full.stderr b/src/test/ui/const-generics/infer/cannot-infer-const-args.full.stderr
index b438ed3ad65..05bf67a5ff7 100644
--- a/src/test/ui/const-generics/infer/cannot-infer-const-args.full.stderr
+++ b/src/test/ui/const-generics/infer/cannot-infer-const-args.full.stderr
@@ -3,6 +3,11 @@ error[E0282]: type annotations needed
    |
 LL |     foo();
    |     ^^^ cannot infer the value of const parameter `X` declared on the function `foo`
+   |
+help: consider specifying the const argument
+   |
+LL |     foo::<X>();
+   |     ^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/const-generics/infer/cannot-infer-const-args.min.stderr b/src/test/ui/const-generics/infer/cannot-infer-const-args.min.stderr
index b438ed3ad65..05bf67a5ff7 100644
--- a/src/test/ui/const-generics/infer/cannot-infer-const-args.min.stderr
+++ b/src/test/ui/const-generics/infer/cannot-infer-const-args.min.stderr
@@ -3,6 +3,11 @@ error[E0282]: type annotations needed
    |
 LL |     foo();
    |     ^^^ cannot infer the value of const parameter `X` declared on the function `foo`
+   |
+help: consider specifying the const argument
+   |
+LL |     foo::<X>();
+   |     ^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/const-generics/infer/issue-77092.stderr b/src/test/ui/const-generics/infer/issue-77092.stderr
index 63facbf3b8c..99894173bc8 100644
--- a/src/test/ui/const-generics/infer/issue-77092.stderr
+++ b/src/test/ui/const-generics/infer/issue-77092.stderr
@@ -3,6 +3,11 @@ error[E0282]: type annotations needed
    |
 LL |         println!("{:?}", take_array_from_mut(&mut arr, i));
    |                          ^^^^^^^^^^^^^^^^^^^ cannot infer the value of const parameter `N` declared on the function `take_array_from_mut`
+   |
+help: consider specifying the const argument
+   |
+LL |         println!("{:?}", take_array_from_mut::<N>(&mut arr, i));
+   |                          ^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/const-generics/infer/method-chain.full.stderr b/src/test/ui/const-generics/infer/method-chain.full.stderr
index 1fb0b23cf11..7aa3bd44df8 100644
--- a/src/test/ui/const-generics/infer/method-chain.full.stderr
+++ b/src/test/ui/const-generics/infer/method-chain.full.stderr
@@ -3,6 +3,11 @@ error[E0282]: type annotations needed
    |
 LL |     Foo.bar().bar().bar().bar().baz();
    |                                 ^^^ cannot infer the value of const parameter `N` declared on the associated function `baz`
+   |
+help: consider specifying the const argument
+   |
+LL |     Foo.bar().bar().bar().bar().baz::<N>();
+   |                                 ^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/const-generics/infer/method-chain.min.stderr b/src/test/ui/const-generics/infer/method-chain.min.stderr
index 1fb0b23cf11..7aa3bd44df8 100644
--- a/src/test/ui/const-generics/infer/method-chain.min.stderr
+++ b/src/test/ui/const-generics/infer/method-chain.min.stderr
@@ -3,6 +3,11 @@ error[E0282]: type annotations needed
    |
 LL |     Foo.bar().bar().bar().bar().baz();
    |                                 ^^^ cannot infer the value of const parameter `N` declared on the associated function `baz`
+   |
+help: consider specifying the const argument
+   |
+LL |     Foo.bar().bar().bar().bar().baz::<N>();
+   |                                 ^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/const-generics/infer/one-param-uninferred.full.stderr b/src/test/ui/const-generics/infer/one-param-uninferred.full.stderr
new file mode 100644
index 00000000000..cc6c9a47510
--- /dev/null
+++ b/src/test/ui/const-generics/infer/one-param-uninferred.full.stderr
@@ -0,0 +1,14 @@
+error[E0282]: type annotations needed
+  --> $DIR/one-param-uninferred.rs:15:23
+   |
+LL |     let _: [u8; 17] = foo();
+   |                       ^^^ cannot infer the value of const parameter `M` declared on the function `foo`
+   |
+help: consider specifying the const argument
+   |
+LL |     let _: [u8; 17] = foo::<M>();
+   |                       ^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0282`.
diff --git a/src/test/ui/const-generics/infer/one-param-uninferred.min.stderr b/src/test/ui/const-generics/infer/one-param-uninferred.min.stderr
new file mode 100644
index 00000000000..cc6c9a47510
--- /dev/null
+++ b/src/test/ui/const-generics/infer/one-param-uninferred.min.stderr
@@ -0,0 +1,14 @@
+error[E0282]: type annotations needed
+  --> $DIR/one-param-uninferred.rs:15:23
+   |
+LL |     let _: [u8; 17] = foo();
+   |                       ^^^ cannot infer the value of const parameter `M` declared on the function `foo`
+   |
+help: consider specifying the const argument
+   |
+LL |     let _: [u8; 17] = foo::<M>();
+   |                       ^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0282`.
diff --git a/src/test/ui/const-generics/infer/one-param-uninferred.rs b/src/test/ui/const-generics/infer/one-param-uninferred.rs
new file mode 100644
index 00000000000..0e947131f4c
--- /dev/null
+++ b/src/test/ui/const-generics/infer/one-param-uninferred.rs
@@ -0,0 +1,17 @@
+// Test that we emit an error if we cannot properly infer a constant.
+// revisions: full min
+
+#![cfg_attr(full, feature(const_generics))]
+#![cfg_attr(full, allow(incomplete_features))]
+#![cfg_attr(min, feature(min_const_generics))]
+
+fn foo<const N: usize, const M: usize>() -> [u8; N] {
+    todo!()
+}
+
+fn main() {
+    // FIXME(const_generics): Currently this only suggests one const parameter,
+    // but instead it should suggest to provide all parameters.
+    let _: [u8; 17] = foo();
+                  //~^ ERROR type annotations needed
+}
diff --git a/src/test/ui/const-generics/infer/uninferred-consts.full.stderr b/src/test/ui/const-generics/infer/uninferred-consts.full.stderr
index 7a451903e96..4be625ba909 100644
--- a/src/test/ui/const-generics/infer/uninferred-consts.full.stderr
+++ b/src/test/ui/const-generics/infer/uninferred-consts.full.stderr
@@ -2,7 +2,12 @@ error[E0282]: type annotations needed
   --> $DIR/uninferred-consts.rs:14:9
    |
 LL |     Foo.foo();
-   |         ^^^ cannot infer the value of const parameter `N` declared on the associated function `foo`
+   |         ^^^ cannot infer the value of const parameter `A` declared on the associated function `foo`
+   |
+help: consider specifying the const argument
+   |
+LL |     Foo.foo::<A>();
+   |         ^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/const-generics/infer/uninferred-consts.min.stderr b/src/test/ui/const-generics/infer/uninferred-consts.min.stderr
index 7a451903e96..4be625ba909 100644
--- a/src/test/ui/const-generics/infer/uninferred-consts.min.stderr
+++ b/src/test/ui/const-generics/infer/uninferred-consts.min.stderr
@@ -2,7 +2,12 @@ error[E0282]: type annotations needed
   --> $DIR/uninferred-consts.rs:14:9
    |
 LL |     Foo.foo();
-   |         ^^^ cannot infer the value of const parameter `N` declared on the associated function `foo`
+   |         ^^^ cannot infer the value of const parameter `A` declared on the associated function `foo`
+   |
+help: consider specifying the const argument
+   |
+LL |     Foo.foo::<A>();
+   |         ^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/const-generics/infer/uninferred-consts.rs b/src/test/ui/const-generics/infer/uninferred-consts.rs
index ec5b3ffe544..00fb6eac992 100644
--- a/src/test/ui/const-generics/infer/uninferred-consts.rs
+++ b/src/test/ui/const-generics/infer/uninferred-consts.rs
@@ -8,7 +8,7 @@
 // taken from https://github.com/rust-lang/rust/issues/70507#issuecomment-615268893
 struct Foo;
 impl Foo {
-    fn foo<const N: usize>(self) {}
+    fn foo<const A: usize, const B: usize>(self) {}
 }
 fn main() {
     Foo.foo();