From 8ca55641fd80ac51971997f903358fa579209d71 Mon Sep 17 00:00:00 2001
From: varkor <github@varkor.com>
Date: Fri, 10 Jan 2020 13:31:36 +0000
Subject: [PATCH] Clarify suggestion for E0013
---
src/librustc_mir/transform/check_consts/ops.rs | 12 +++++++-----
.../ui/consts/const-fn-not-safe-for-const.stderr | 8 ++++++--
.../ui/issues/issue-17718-const-bad-values.stderr | 8 ++++++--
src/test/ui/issues/issue-17718-references.stderr | 12 +++++++++---
src/test/ui/issues/issue-18118-2.rs | 3 +--
src/test/ui/issues/issue-18118-2.stderr | 4 +++-
src/test/ui/issues/issue-52060.stderr | 4 +++-
7 files changed, 35 insertions(+), 16 deletions(-)
diff --git a/src/librustc_mir/transform/check_consts/ops.rs b/src/librustc_mir/transform/check_consts/ops.rs
index abef008a8ec..e4188092827 100644
--- a/src/librustc_mir/transform/check_consts/ops.rs
+++ b/src/librustc_mir/transform/check_consts/ops.rs
@@ -350,16 +350,18 @@ impl NonConstOp for StaticAccess {
item.tcx.sess,
span,
E0013,
- "{}s cannot refer to statics, use \
- a constant instead",
+ "{}s cannot refer to statics",
item.const_kind()
);
+ err.help(
+ "consider extracting the value of the `static` to a `const`, and referring to that",
+ );
if item.tcx.sess.teach(&err.get_code().unwrap()) {
err.note(
- "Static and const variables can refer to other const variables. \
- But a const variable cannot refer to a static variable.",
+ "`static` and `const` variables can refer to other `const` variables. \
+ A `const` variable, however, cannot refer to a `static` variable.",
);
- err.help("To fix this, the value can be extracted as a const and then used.");
+ err.help("To fix this, the value can be extracted to a `const` and then used.");
}
err.emit();
}
diff --git a/src/test/ui/consts/const-fn-not-safe-for-const.stderr b/src/test/ui/consts/const-fn-not-safe-for-const.stderr
index 2d4175ea8eb..df793d7dd7e 100644
--- a/src/test/ui/consts/const-fn-not-safe-for-const.stderr
+++ b/src/test/ui/consts/const-fn-not-safe-for-const.stderr
@@ -4,17 +4,21 @@ error[E0015]: calls in constant functions are limited to constant functions, tup
LL | random()
| ^^^^^^^^
-error[E0013]: constant functions cannot refer to statics, use a constant instead
+error[E0013]: constant functions cannot refer to statics
--> $DIR/const-fn-not-safe-for-const.rs:20:5
|
LL | Y
| ^
+ |
+ = help: consider extracting the value of the `static` to a `const`, and referring to that
-error[E0013]: constant functions cannot refer to statics, use a constant instead
+error[E0013]: constant functions cannot refer to statics
--> $DIR/const-fn-not-safe-for-const.rs:25:6
|
LL | &Y
| ^
+ |
+ = help: consider extracting the value of the `static` to a `const`, and referring to that
error: aborting due to 3 previous errors
diff --git a/src/test/ui/issues/issue-17718-const-bad-values.stderr b/src/test/ui/issues/issue-17718-const-bad-values.stderr
index 14bf5dc38b4..e45d8b6c740 100644
--- a/src/test/ui/issues/issue-17718-const-bad-values.stderr
+++ b/src/test/ui/issues/issue-17718-const-bad-values.stderr
@@ -7,17 +7,21 @@ LL | const C1: &'static mut [usize] = &mut [];
= note: for more information, see https://github.com/rust-lang/rust/issues/57349
= help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
--> $DIR/issue-17718-const-bad-values.rs:5:46
|
LL | const C2: &'static mut usize = unsafe { &mut S };
| ^
+ |
+ = help: consider extracting the value of the `static` to a `const`, and referring to that
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
--> $DIR/issue-17718-const-bad-values.rs:5:46
|
LL | const C2: &'static mut usize = unsafe { &mut S };
| ^
+ |
+ = help: consider extracting the value of the `static` to a `const`, and referring to that
error[E0658]: references in constants may only refer to immutable values
--> $DIR/issue-17718-const-bad-values.rs:5:41
diff --git a/src/test/ui/issues/issue-17718-references.stderr b/src/test/ui/issues/issue-17718-references.stderr
index 27aad9c03ce..e3c3b369ffb 100644
--- a/src/test/ui/issues/issue-17718-references.stderr
+++ b/src/test/ui/issues/issue-17718-references.stderr
@@ -1,20 +1,26 @@
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
--> $DIR/issue-17718-references.rs:9:29
|
LL | const T2: &'static usize = &S;
| ^
+ |
+ = help: consider extracting the value of the `static` to a `const`, and referring to that
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
--> $DIR/issue-17718-references.rs:14:19
|
LL | const T6: usize = S;
| ^
+ |
+ = help: consider extracting the value of the `static` to a `const`, and referring to that
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
--> $DIR/issue-17718-references.rs:19:33
|
LL | const T10: Struct = Struct { a: S };
| ^
+ |
+ = help: consider extracting the value of the `static` to a `const`, and referring to that
error: aborting due to 3 previous errors
diff --git a/src/test/ui/issues/issue-18118-2.rs b/src/test/ui/issues/issue-18118-2.rs
index 6d52156b3d2..f712a2eedb7 100644
--- a/src/test/ui/issues/issue-18118-2.rs
+++ b/src/test/ui/issues/issue-18118-2.rs
@@ -1,7 +1,6 @@
pub fn main() {
const z: &'static isize = {
static p: isize = 3;
- &p
- //~^ ERROR constants cannot refer to statics, use a constant instead
+ &p //~ ERROR constants cannot refer to statics
};
}
diff --git a/src/test/ui/issues/issue-18118-2.stderr b/src/test/ui/issues/issue-18118-2.stderr
index d58822f16eb..4fc3ca78f96 100644
--- a/src/test/ui/issues/issue-18118-2.stderr
+++ b/src/test/ui/issues/issue-18118-2.stderr
@@ -1,8 +1,10 @@
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
--> $DIR/issue-18118-2.rs:4:10
|
LL | &p
| ^
+ |
+ = help: consider extracting the value of the `static` to a `const`, and referring to that
error: aborting due to previous error
diff --git a/src/test/ui/issues/issue-52060.stderr b/src/test/ui/issues/issue-52060.stderr
index c69145c1fe8..502825e9766 100644
--- a/src/test/ui/issues/issue-52060.stderr
+++ b/src/test/ui/issues/issue-52060.stderr
@@ -1,8 +1,10 @@
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
--> $DIR/issue-52060.rs:4:26
|
LL | static B: [u32; 1] = [0; A.len()];
| ^
+ |
+ = help: consider extracting the value of the `static` to a `const`, and referring to that
error[E0080]: evaluation of constant value failed
--> $DIR/issue-52060.rs:4:26