Auto merge of #84564 - Dylan-DPC:rollup-wxa2yr0, r=Dylan-DPC

Rollup of 8 pull requests

Successful merges:

 - #84235 (refactor StyledBuffer)
 - #84450 (Give a better error when `std` or `core` are missing)
 - #84486 (Handle pretty printing of `else if let` clauses without ICEing)
 - #84499 (Tweak trait not `use`d suggestion)
 - #84516 (Add suggestion to "use break" when attempting to implicit-break a loop)
 - #84520 (Improve diagnostics for function passed when a type was expected.)
 - #84541 (Inline most raw socket, fd and handle conversions)
 - #84547 (Get rid of is_min_const_fn)

Failed merges:

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

27 files changed, 323 insertions, 30 deletions

diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index e88a739d042..3986167bac8 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -10,7 +10,6 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::Mutability;
 use rustc_metadata::creader::LoadedMacro;
 use rustc_middle::ty::{self, TyCtxt};
-use rustc_mir::const_eval::is_min_const_fn;
 use rustc_span::hygiene::MacroKind;
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_span::Span;
@@ -210,7 +209,7 @@ fn build_external_function(cx: &mut DocContext<'_>, did: DefId) -> clean::Functi
     let sig = cx.tcx.fn_sig(did);
 
     let constness =
-        if is_min_const_fn(cx.tcx, did) { hir::Constness::Const } else { hir::Constness::NotConst };
+        if cx.tcx.is_const_fn_raw(did) { hir::Constness::Const } else { hir::Constness::NotConst };
     let asyncness = cx.tcx.asyncness(did);
     let predicates = cx.tcx.predicates_of(did);
     let (generics, decl) = clean::enter_impl_trait(cx, |cx| {
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index c0a8c88bdeb..6b04157d953 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -22,7 +22,7 @@ use rustc_middle::middle::resolve_lifetime as rl;
 use rustc_middle::ty::fold::TypeFolder;
 use rustc_middle::ty::subst::{InternalSubsts, Subst};
 use rustc_middle::ty::{self, AdtKind, Lift, Ty, TyCtxt};
-use rustc_mir::const_eval::{is_const_fn, is_min_const_fn, is_unstable_const_fn};
+use rustc_mir::const_eval::{is_const_fn, is_unstable_const_fn};
 use rustc_span::hygiene::{AstPass, MacroKind};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{self, ExpnKind};
@@ -1048,7 +1048,7 @@ impl Clean<Item> for ty::AssocItem {
                     ty::TraitContainer(_) => self.defaultness.has_value(),
                 };
                 if provided {
-                    let constness = if is_min_const_fn(tcx, self.def_id) {
+                    let constness = if tcx.is_const_fn_raw(self.def_id) {
                         hir::Constness::Const
                     } else {
                         hir::Constness::NotConst
diff --git a/src/test/ui/cast/cast-ptr-to-int-const.rs b/src/test/ui/cast/cast-ptr-to-int-const.rs
index ac153cb5742..aed099a53ea 100644
--- a/src/test/ui/cast/cast-ptr-to-int-const.rs
+++ b/src/test/ui/cast/cast-ptr-to-int-const.rs
@@ -1,11 +1,25 @@
 // gate-test-const_raw_ptr_to_usize_cast
+// revisions: with_feature without_feature
+
+#![cfg_attr(with_feature, feature(const_raw_ptr_to_usize_cast))]
 
 fn main() {
-    const X: u32 = unsafe {
-        main as u32 //~ ERROR casting pointers to integers in constants is unstable
+    const X: usize = unsafe {
+        main as usize //[without_feature]~ ERROR casting pointers to integers in constants is unstable
     };
     const Y: u32 = 0;
-    const Z: u32 = unsafe {
-        &Y as *const u32 as u32 //~ ERROR is unstable
+    const Z: usize = unsafe {
+        &Y as *const u32 as usize //[without_feature]~ ERROR is unstable
+    };
+    // Cast in `const` without `unsafe` block
+    const SAFE: usize = {
+        &Y as *const u32 as usize //[without_feature]~ ERROR is unstable
+        //[with_feature]~^ ERROR cast of pointer to int is unsafe and requires unsafe
     };
 }
+
+// Cast in `const fn` without `unsafe` block
+const fn test() -> usize {
+    &0 as *const i32 as usize //[without_feature]~ ERROR is unstable
+    //[with_feature]~^ ERROR cast of pointer to int is unsafe and requires unsafe
+}
diff --git a/src/test/ui/cast/cast-ptr-to-int-const.stderr b/src/test/ui/cast/cast-ptr-to-int-const.stderr
deleted file mode 100644
index f523b14a98c..00000000000
--- a/src/test/ui/cast/cast-ptr-to-int-const.stderr
+++ /dev/null
@@ -1,21 +0,0 @@
-error[E0658]: casting pointers to integers in constants is unstable
-  --> $DIR/cast-ptr-to-int-const.rs:5:9
-   |
-LL |         main as u32
-   |         ^^^^^^^^^^^
-   |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
-
-error[E0658]: casting pointers to integers in constants is unstable
-  --> $DIR/cast-ptr-to-int-const.rs:9:9
-   |
-LL |         &Y as *const u32 as u32
-   |         ^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
-   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/cast/cast-ptr-to-int-const.with_feature.stderr b/src/test/ui/cast/cast-ptr-to-int-const.with_feature.stderr
new file mode 100644
index 00000000000..8282bc3db05
--- /dev/null
+++ b/src/test/ui/cast/cast-ptr-to-int-const.with_feature.stderr
@@ -0,0 +1,19 @@
+error[E0133]: cast of pointer to int is unsafe and requires unsafe function or block
+  --> $DIR/cast-ptr-to-int-const.rs:16:9
+   |
+LL |         &Y as *const u32 as usize
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^ cast of pointer to int
+   |
+   = note: casting pointers to integers in constants
+
+error[E0133]: cast of pointer to int is unsafe and requires unsafe function or block
+  --> $DIR/cast-ptr-to-int-const.rs:23:5
+   |
+LL |     &0 as *const i32 as usize
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ cast of pointer to int
+   |
+   = note: casting pointers to integers in constants
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0133`.
diff --git a/src/test/ui/cast/cast-ptr-to-int-const.without_feature.stderr b/src/test/ui/cast/cast-ptr-to-int-const.without_feature.stderr
new file mode 100644
index 00000000000..c87fa1a14a4
--- /dev/null
+++ b/src/test/ui/cast/cast-ptr-to-int-const.without_feature.stderr
@@ -0,0 +1,39 @@
+error[E0658]: casting pointers to integers in constants is unstable
+  --> $DIR/cast-ptr-to-int-const.rs:8:9
+   |
+LL |         main as usize
+   |         ^^^^^^^^^^^^^
+   |
+   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
+   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+
+error[E0658]: casting pointers to integers in constants is unstable
+  --> $DIR/cast-ptr-to-int-const.rs:12:9
+   |
+LL |         &Y as *const u32 as usize
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
+   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+
+error[E0658]: casting pointers to integers in constants is unstable
+  --> $DIR/cast-ptr-to-int-const.rs:16:9
+   |
+LL |         &Y as *const u32 as usize
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
+   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+
+error[E0658]: casting pointers to integers in constant functions is unstable
+  --> $DIR/cast-ptr-to-int-const.rs:23:5
+   |
+LL |     &0 as *const i32 as usize
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
+   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/crate-loading/missing-std.rs b/src/test/ui/crate-loading/missing-std.rs
new file mode 100644
index 00000000000..442a7c01e5a
--- /dev/null
+++ b/src/test/ui/crate-loading/missing-std.rs
@@ -0,0 +1,11 @@
+// compile-flags: --target x86_64-unknown-uefi
+// rustc-env:CARGO=/usr/bin/cargo
+// rustc-env:RUSTUP_HOME=/home/bors/.rustup
+#![no_core]
+extern crate core;
+//~^ ERROR can't find crate for `core`
+//~| NOTE can't find crate
+//~| NOTE target may not be installed
+//~| HELP consider building the standard library from source with `cargo build -Zbuild-std`
+//~| HELP consider downloading the target with `rustup target add x86_64-unknown-uefi`
+fn main() {}
diff --git a/src/test/ui/crate-loading/missing-std.stderr b/src/test/ui/crate-loading/missing-std.stderr
new file mode 100644
index 00000000000..25808efdfa6
--- /dev/null
+++ b/src/test/ui/crate-loading/missing-std.stderr
@@ -0,0 +1,13 @@
+error[E0463]: can't find crate for `core`
+  --> $DIR/missing-std.rs:5:1
+   |
+LL | extern crate core;
+   | ^^^^^^^^^^^^^^^^^^ can't find crate
+   |
+   = note: the `x86_64-unknown-uefi` target may not be installed
+   = help: consider downloading the target with `rustup target add x86_64-unknown-uefi`
+   = help: consider building the standard library from source with `cargo build -Zbuild-std`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0463`.
diff --git a/src/test/ui/generics/generic-function-item-where-type.rs b/src/test/ui/generics/generic-function-item-where-type.rs
new file mode 100644
index 00000000000..e1b0578cadb
--- /dev/null
+++ b/src/test/ui/generics/generic-function-item-where-type.rs
@@ -0,0 +1,6 @@
+fn foo<U>() {}
+
+fn main() {
+    foo::<main>()
+    //~^ ERROR constant provided when a type was expected
+}
diff --git a/src/test/ui/generics/generic-function-item-where-type.stderr b/src/test/ui/generics/generic-function-item-where-type.stderr
new file mode 100644
index 00000000000..88594129caa
--- /dev/null
+++ b/src/test/ui/generics/generic-function-item-where-type.stderr
@@ -0,0 +1,12 @@
+error[E0747]: constant provided when a type was expected
+  --> $DIR/generic-function-item-where-type.rs:4:11
+   |
+LL |     foo::<main>()
+   |           ^^^^
+   |
+   = help: `main` is a function item, not a type
+   = help: function item types cannot be named directly
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0747`.
diff --git a/src/test/ui/hygiene/trait_items.stderr b/src/test/ui/hygiene/trait_items.stderr
index d24336883e9..2913a955dce 100644
--- a/src/test/ui/hygiene/trait_items.stderr
+++ b/src/test/ui/hygiene/trait_items.stderr
@@ -1,6 +1,9 @@
 error[E0599]: no method named `f` found for unit type `()` in the current scope
   --> $DIR/trait_items.rs:17:24
    |
+LL |         fn f(&self) {}
+   |            - the method is available for `()` here
+...
 LL |     fn f() { ::baz::m!(); }
    |              ------------ in this macro invocation
 ...
diff --git a/src/test/ui/impl-trait/no-method-suggested-traits.stderr b/src/test/ui/impl-trait/no-method-suggested-traits.stderr
index 64ddcb81c0a..b993115502f 100644
--- a/src/test/ui/impl-trait/no-method-suggested-traits.stderr
+++ b/src/test/ui/impl-trait/no-method-suggested-traits.stderr
@@ -37,6 +37,9 @@ LL | use no_method_suggested_traits::Reexported;
 error[E0599]: no method named `method` found for type `char` in the current scope
   --> $DIR/no-method-suggested-traits.rs:30:9
    |
+LL |         fn method(&self) {}
+   |            ------ the method is available for `char` here
+...
 LL |     'a'.method();
    |         ^^^^^^ method not found in `char`
    |
@@ -63,6 +66,11 @@ error[E0599]: no method named `method` found for type `i32` in the current scope
    |
 LL |     1i32.method();
    |          ^^^^^^ method not found in `i32`
+   | 
+  ::: $DIR/auxiliary/no_method_suggested_traits.rs:8:12
+   |
+LL |         fn method(&self) {}
+   |            ------ the method is available for `i32` here
    |
    = help: items from traits can only be used if the trait is in scope
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
diff --git a/src/test/ui/issues/issue-43189.stderr b/src/test/ui/issues/issue-43189.stderr
index 3f63cb8e78f..3a3767c349d 100644
--- a/src/test/ui/issues/issue-43189.stderr
+++ b/src/test/ui/issues/issue-43189.stderr
@@ -3,6 +3,11 @@ error[E0599]: no method named `a` found for unit type `()` in the current scope
    |
 LL |     ().a();
    |        ^ method not found in `()`
+   | 
+  ::: $DIR/auxiliary/xcrate-issue-43189-a.rs:5:8
+   |
+LL |     fn a(&self) {}
+   |        - the method is available for `()` here
    |
    = help: items from traits can only be used if the trait is in scope
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
diff --git a/src/test/ui/issues/issue-56175.stderr b/src/test/ui/issues/issue-56175.stderr
index ee3f609f47d..e6b0fffce66 100644
--- a/src/test/ui/issues/issue-56175.stderr
+++ b/src/test/ui/issues/issue-56175.stderr
@@ -3,6 +3,11 @@ error[E0599]: no method named `trait_method` found for struct `FooStruct` in the
    |
 LL |     reexported_trait::FooStruct.trait_method();
    |                                 ^^^^^^^^^^^^ method not found in `FooStruct`
+   | 
+  ::: $DIR/auxiliary/reexported-trait.rs:3:12
+   |
+LL |         fn trait_method(&self) {
+   |            ------------ the method is available for `FooStruct` here
    |
    = help: items from traits can only be used if the trait is in scope
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
@@ -15,6 +20,11 @@ error[E0599]: no method named `trait_method_b` found for struct `FooStruct` in t
    |
 LL |     reexported_trait::FooStruct.trait_method_b();
    |                                 ^^^^^^^^^^^^^^ method not found in `FooStruct`
+   | 
+  ::: $DIR/auxiliary/reexported-trait.rs:7:12
+   |
+LL |         fn trait_method_b(&self) {
+   |            -------------- the method is available for `FooStruct` here
    |
    = help: items from traits can only be used if the trait is in scope
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
diff --git a/src/test/ui/loops/loop-no-implicit-break.rs b/src/test/ui/loops/loop-no-implicit-break.rs
new file mode 100644
index 00000000000..93078cb4b14
--- /dev/null
+++ b/src/test/ui/loops/loop-no-implicit-break.rs
@@ -0,0 +1,31 @@
+fn main() {
+    let a: i8 = loop {
+        1 //~ ERROR mismatched types
+    };
+
+    let b: i8 = loop {
+        break 1;
+    };
+}
+
+fn foo() -> i8 {
+    let a: i8 = loop {
+        1 //~ ERROR mismatched types
+    };
+
+    let b: i8 = loop {
+        break 1;
+    };
+
+    loop {
+        1 //~ ERROR mismatched types
+    }
+
+    loop {
+        return 1;
+    }
+
+    loop {
+        1 //~ ERROR mismatched types
+    }
+}
diff --git a/src/test/ui/loops/loop-no-implicit-break.stderr b/src/test/ui/loops/loop-no-implicit-break.stderr
new file mode 100644
index 00000000000..5087662e7bf
--- /dev/null
+++ b/src/test/ui/loops/loop-no-implicit-break.stderr
@@ -0,0 +1,47 @@
+error[E0308]: mismatched types
+  --> $DIR/loop-no-implicit-break.rs:3:9
+   |
+LL |         1
+   |         ^ expected `()`, found integer
+   |
+help: you might have meant to break the loop with this value
+   |
+LL |         break 1;
+   |         ^^^^^  ^
+
+error[E0308]: mismatched types
+  --> $DIR/loop-no-implicit-break.rs:13:9
+   |
+LL |         1
+   |         ^ expected `()`, found integer
+   |
+help: you might have meant to break the loop with this value
+   |
+LL |         break 1;
+   |         ^^^^^  ^
+
+error[E0308]: mismatched types
+  --> $DIR/loop-no-implicit-break.rs:21:9
+   |
+LL |         1
+   |         ^ expected `()`, found integer
+   |
+help: you might have meant to return this value
+   |
+LL |         return 1;
+   |         ^^^^^^  ^
+
+error[E0308]: mismatched types
+  --> $DIR/loop-no-implicit-break.rs:29:9
+   |
+LL |         1
+   |         ^ expected `()`, found integer
+   |
+help: you might have meant to return this value
+   |
+LL |         return 1;
+   |         ^^^^^^  ^
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/match/issue-82392.rs b/src/test/ui/match/issue-82392.rs
new file mode 100644
index 00000000000..d26d883040b
--- /dev/null
+++ b/src/test/ui/match/issue-82392.rs
@@ -0,0 +1,9 @@
+// https://github.com/rust-lang/rust/issues/82329
+// compile-flags: -Zunpretty=hir,typed
+// check-pass
+
+pub fn main() {
+    if true {
+    } else if let Some(a) = Some(3) {
+    }
+}
diff --git a/src/test/ui/match/issue-82392.stdout b/src/test/ui/match/issue-82392.stdout
new file mode 100644
index 00000000000..8ff76c64fc7
--- /dev/null
+++ b/src/test/ui/match/issue-82392.stdout
@@ -0,0 +1,20 @@
+#[prelude_import]
+use ::std::prelude::rust_2015::*;
+#[macro_use]
+extern crate std;
+// https://github.com/rust-lang/rust/issues/82329
+// compile-flags: -Zunpretty=hir,typed
+// check-pass
+
+pub fn main() ({
+                   (if (true as bool)
+                       ({ } as
+                           ()) else {match ((Some as
+                                                fn(i32) -> Option<i32> {Option::<i32>::Some})((3
+                                                                                                  as
+                                                                                                  i32))
+                                               as Option<i32>) {
+                                         Some(a) => { }
+                                         _ => { }
+                                     }} as ())
+                    } as ())
diff --git a/src/test/ui/match/issue-84434.rs b/src/test/ui/match/issue-84434.rs
new file mode 100644
index 00000000000..423481fd5f0
--- /dev/null
+++ b/src/test/ui/match/issue-84434.rs
@@ -0,0 +1,18 @@
+// https://github.com/rust-lang/rust/issues/84434
+// check-pass
+
+use std::path::Path;
+struct A {
+    pub func: fn(check: bool, a: &Path, b: Option<&Path>),
+}
+const MY_A: A = A {
+    func: |check, a, b| {
+        if check {
+            let _ = ();
+        } else if let Some(parent) = b.and_then(|p| p.parent()) {
+            let _ = ();
+        }
+    },
+};
+
+fn main() {}
diff --git a/src/test/ui/privacy/privacy-ns1.stderr b/src/test/ui/privacy/privacy-ns1.stderr
index 714f28941f1..d09a8aae748 100644
--- a/src/test/ui/privacy/privacy-ns1.stderr
+++ b/src/test/ui/privacy/privacy-ns1.stderr
@@ -57,6 +57,9 @@ error[E0747]: constant provided when a type was expected
    |
 LL |     let _x: Box<Bar>;
    |                 ^^^
+   |
+   = help: `Bar` is a function item, not a type
+   = help: function item types cannot be named directly
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/privacy/privacy-ns2.stderr b/src/test/ui/privacy/privacy-ns2.stderr
index c7ad8ec5036..fdf0549cf50 100644
--- a/src/test/ui/privacy/privacy-ns2.stderr
+++ b/src/test/ui/privacy/privacy-ns2.stderr
@@ -83,12 +83,18 @@ error[E0747]: constant provided when a type was expected
    |
 LL |     let _x : Box<Bar>;
    |                  ^^^
+   |
+   = help: `Bar` is a function item, not a type
+   = help: function item types cannot be named directly
 
 error[E0747]: constant provided when a type was expected
   --> $DIR/privacy-ns2.rs:48:17
    |
 LL |     let _x: Box<Bar>;
    |                 ^^^
+   |
+   = help: `Bar` is a function item, not a type
+   = help: function item types cannot be named directly
 
 error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/rust-2018/trait-import-suggestions.stderr b/src/test/ui/rust-2018/trait-import-suggestions.stderr
index 4b1898345a3..2cf5a073fe5 100644
--- a/src/test/ui/rust-2018/trait-import-suggestions.stderr
+++ b/src/test/ui/rust-2018/trait-import-suggestions.stderr
@@ -1,6 +1,9 @@
 error[E0599]: no method named `foobar` found for type `u32` in the current scope
   --> $DIR/trait-import-suggestions.rs:22:11
    |
+LL |             fn foobar(&self) { }
+   |                ------ the method is available for `u32` here
+...
 LL |         x.foobar();
    |           ^^^^^^ method not found in `u32`
    |
@@ -11,6 +14,9 @@ LL |         x.foobar();
 error[E0599]: no method named `bar` found for type `u32` in the current scope
   --> $DIR/trait-import-suggestions.rs:28:7
    |
+LL |         fn bar(&self) { }
+   |            --- the method is available for `u32` here
+...
 LL |     x.bar();
    |       ^^^ method not found in `u32`
    |
diff --git a/src/test/ui/shadowed/shadowed-trait-methods.stderr b/src/test/ui/shadowed/shadowed-trait-methods.stderr
index 362907ecbd7..c3b9084affd 100644
--- a/src/test/ui/shadowed/shadowed-trait-methods.stderr
+++ b/src/test/ui/shadowed/shadowed-trait-methods.stderr
@@ -1,6 +1,9 @@
 error[E0599]: no method named `f` found for unit type `()` in the current scope
   --> $DIR/shadowed-trait-methods.rs:13:8
    |
+LL |     pub trait T { fn f(&self) {} }
+   |                      - the method is available for `()` here
+...
 LL |     ().f()
    |        ^ method not found in `()`
    |
diff --git a/src/test/ui/suggestions/import-trait-for-method-call.rs b/src/test/ui/suggestions/import-trait-for-method-call.rs
new file mode 100644
index 00000000000..646f68dea14
--- /dev/null
+++ b/src/test/ui/suggestions/import-trait-for-method-call.rs
@@ -0,0 +1,9 @@
+use std::hash::BuildHasher;
+
+fn next_u64() -> u64 {
+    let bh = std::collections::hash_map::RandomState::new();
+    let h = bh.build_hasher();
+    h.finish() //~ ERROR no method named `finish` found for struct `DefaultHasher`
+}
+
+fn main() {}
diff --git a/src/test/ui/suggestions/import-trait-for-method-call.stderr b/src/test/ui/suggestions/import-trait-for-method-call.stderr
new file mode 100644
index 00000000000..f3ae20552f3
--- /dev/null
+++ b/src/test/ui/suggestions/import-trait-for-method-call.stderr
@@ -0,0 +1,20 @@
+error[E0599]: no method named `finish` found for struct `DefaultHasher` in the current scope
+  --> $DIR/import-trait-for-method-call.rs:6:7
+   |
+LL |     h.finish()
+   |       ^^^^^^ method not found in `DefaultHasher`
+   | 
+  ::: $SRC_DIR/core/src/hash/mod.rs:LL:COL
+   |
+LL |     fn finish(&self) -> u64;
+   |        ------ the method is available for `DefaultHasher` here
+   |
+   = help: items from traits can only be used if the trait is in scope
+help: the following trait is implemented but not in scope; perhaps add a `use` for it:
+   |
+LL | use std::hash::Hasher;
+   |
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0599`.
diff --git a/src/test/ui/traits/item-privacy.stderr b/src/test/ui/traits/item-privacy.stderr
index 68d527dc786..30daf8e2770 100644
--- a/src/test/ui/traits/item-privacy.stderr
+++ b/src/test/ui/traits/item-privacy.stderr
@@ -20,6 +20,9 @@ error[E0599]: no method named `b` found for struct `S` in the current scope
 LL | struct S;
    | --------- method `b` not found for this
 ...
+LL |         fn b(&self) { }
+   |            - the method is available for `S` here
+...
 LL |     S.b();
    |       ^ method not found in `S`
    |
diff --git a/src/tools/clippy/clippy_lints/src/missing_const_for_fn.rs b/src/tools/clippy/clippy_lints/src/missing_const_for_fn.rs
index 93b7a897405..60425ff853b 100644
--- a/src/tools/clippy/clippy_lints/src/missing_const_for_fn.rs
+++ b/src/tools/clippy/clippy_lints/src/missing_const_for_fn.rs
@@ -139,7 +139,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingConstForFn {
         let mir = cx.tcx.optimized_mir(def_id);
 
         if let Err((span, err)) = is_min_const_fn(cx.tcx, mir, self.msrv.as_ref()) {
-            if rustc_mir::const_eval::is_min_const_fn(cx.tcx, def_id.to_def_id()) {
+            if cx.tcx.is_const_fn_raw(def_id.to_def_id()) {
                 cx.tcx.sess.span_err(span, &err);
             }
         } else {