Auto merge of #82935 - henryboisdequin:diagnostic-cleanups, r=estebank

Diagnostic cleanups

Follow up to #81503
Helps with #82916 (don't show note if `span` is `DUMMY_SP`)

Author: bors

compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs

@@ -13,7 +13,7 @@ use rustc_middle::mir::{
 use rustc_middle::ty::{self, suggest_constraining_type_param, Ty, TypeFoldable};
 use rustc_span::source_map::DesugaringKind;
 use rustc_span::symbol::sym;
-use rustc_span::Span;
+use rustc_span::{Span, DUMMY_SP};
 
 use crate::dataflow::drop_flag_effects;
 use crate::dataflow::indexes::{MoveOutIndex, MovePathIndex};
@@ -216,12 +216,13 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                 );
                             }
                             // Avoid pointing to the same function in multiple different
-                            // error messages
-                            if self.fn_self_span_reported.insert(self_arg.span) {
+                            // error messages.
+                            if span != DUMMY_SP && self.fn_self_span_reported.insert(self_arg.span)
+                            {
                                 err.span_note(
-                                    self_arg.span,
-                                    &format!("this function takes ownership of the receiver `self`, which moves {}", place_name)
-                                );
+                                        self_arg.span,
+                                        &format!("this function takes ownership of the receiver `self`, which moves {}", place_name)
+                                    );
                             }
                         }
                         // Deref::deref takes &self, which cannot cause a move

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -1908,15 +1908,15 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
 
                 if is_const_fn {
                     err.help(
-                        "consider creating a new `const` item and initializing with the result \
+                        "consider creating a new `const` item and initializing it with the result \
                         of the function call to be used in the repeat position, like \
                         `const VAL: Type = const_fn();` and `let x = [VAL; 42];`",
                     );
                 }
 
                 if self.tcx.sess.is_nightly_build() && is_const_fn {
                     err.help(
-                        "create an inline `const` block, see PR \
+                        "create an inline `const` block, see RFC \
                         #2920 <https://github.com/rust-lang/rfcs/pull/2920> \
                         for more information",
                     );

src/test/ui/consts/const-blocks/fn-call-in-non-const.stderr

@@ -7,8 +7,8 @@ LL |     let _: [Option<Bar>; 2] = [no_copy(); 2];
    = help: the following implementations were found:
              <Option<T> as Copy>
    = note: the `Copy` trait is required because the repeated element will be copied
-   = help: consider creating a new `const` item and initializing with the result of the function call to be used in the repeat position, like `const VAL: Type = const_fn();` and `let x = [VAL; 42];`
-   = help: create an inline `const` block, see PR #2920 <https://github.com/rust-lang/rfcs/pull/2920> for more information
+   = help: consider creating a new `const` item and initializing it with the result of the function call to be used in the repeat position, like `const VAL: Type = const_fn();` and `let x = [VAL; 42];`
+   = help: create an inline `const` block, see RFC #2920 <https://github.com/rust-lang/rfcs/pull/2920> for more information
 
 error: aborting due to previous error
 

src/test/ui/consts/const-fn-in-vec.stderr

@@ -5,8 +5,8 @@ LL |     let strings: [String; 5] = [String::new(); 5];
    |                                ^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `String`
    |
    = note: the `Copy` trait is required because the repeated element will be copied
-   = help: consider creating a new `const` item and initializing with the result of the function call to be used in the repeat position, like `const VAL: Type = const_fn();` and `let x = [VAL; 42];`
-   = help: create an inline `const` block, see PR #2920 <https://github.com/rust-lang/rfcs/pull/2920> for more information
+   = help: consider creating a new `const` item and initializing it with the result of the function call to be used in the repeat position, like `const VAL: Type = const_fn();` and `let x = [VAL; 42];`
+   = help: create an inline `const` block, see RFC #2920 <https://github.com/rust-lang/rfcs/pull/2920> for more information
 
 error: aborting due to previous error
 

src/test/ui/loops/issue-82916.rs

@@ -0,0 +1,10 @@
+struct S(i32);
+
+fn foo(x: Vec<S>) {
+    for y in x {
+
+    }
+    let z = x; //~ ERROR use of moved value: `x`
+}
+
+fn main() {}

src/test/ui/loops/issue-82916.stderr

@@ -0,0 +1,23 @@
+error[E0382]: use of moved value: `x`
+  --> $DIR/issue-82916.rs:7:13
+   |
+LL | fn foo(x: Vec<S>) {
+   |        - move occurs because `x` has type `Vec<S>`, which does not implement the `Copy` trait
+LL |     for y in x {
+   |              -
+   |              |
+   |              `x` moved due to this implicit call to `.into_iter()`
+   |              help: consider borrowing to avoid moving into the for loop: `&x`
+...
+LL |     let z = x;
+   |             ^ value used here after move
+   |
+note: this function takes ownership of the receiver `self`, which moves `x`
+  --> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
+   |
+LL |     fn into_iter(self) -> Self::IntoIter;
+   |                  ^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0382`.