From 48167bd4bddec03d1969e2cc2c1155cb5667d6ad Mon Sep 17 00:00:00 2001
From: Alexander Zhang <alex@alexyzhang.dev>
Date: Thu, 22 Jun 2023 16:37:52 -0700
Subject: Avoid guessing unknown trait impl in suggestions

When a trait is used without specifying the implementation (e.g. calling
a non-member associated function without fully-qualified syntax) and
there are multiple implementations available, use a placeholder comment
for the implementation type in the suggestion instead of picking a
random implementation.

Example:

```
fn main() {
    let _ = Default::default();
}
```

Previous output:

```
error[E0790]: cannot call associated function on trait without specifying the corresponding `impl` type
 --> test.rs:2:13
  |
2 |     let _ = Default::default();
  |             ^^^^^^^^^^^^^^^^ cannot call associated function of trait
  |
help: use a fully-qualified path to a specific available implementation (273 found)
  |
2 |     let _ = <FileTimes as Default>::default();
  |             +++++++++++++        +
```

New output:

```
error[E0790]: cannot call associated function on trait without specifying the corresponding `impl` type
 --> test.rs:2:13
  |
2 |     let _ = Default::default();
  |             ^^^^^^^^^^^^^^^^ cannot call associated function of trait
  |
help: use a fully-qualified path to a specific available implementation (273 found)
  |
2 |     let _ = </* self type */ as Default>::default();
  |             +++++++++++++++++++        +
```
---
 tests/ui/error-codes/E0283.stderr | 4 ++--
 tests/ui/error-codes/E0790.stderr | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

(limited to 'tests/ui/error-codes')

diff --git a/tests/ui/error-codes/E0283.stderr b/tests/ui/error-codes/E0283.stderr
index 90316c6e981..89e634a7064 100644
--- a/tests/ui/error-codes/E0283.stderr
+++ b/tests/ui/error-codes/E0283.stderr
@@ -9,8 +9,8 @@ LL |     let cont: u32 = Generator::create();
    |
 help: use a fully-qualified path to a specific available implementation (2 found)
    |
-LL |     let cont: u32 = <Impl as Generator>::create();
-   |                     ++++++++          +
+LL |     let cont: u32 = </* self type */ as Generator>::create();
+   |                     +++++++++++++++++++          +
 
 error[E0283]: type annotations needed
   --> $DIR/E0283.rs:35:24
diff --git a/tests/ui/error-codes/E0790.stderr b/tests/ui/error-codes/E0790.stderr
index fc025a3fca2..7248766285d 100644
--- a/tests/ui/error-codes/E0790.stderr
+++ b/tests/ui/error-codes/E0790.stderr
@@ -65,8 +65,8 @@ LL |     MyTrait2::my_fn();
    |
 help: use a fully-qualified path to a specific available implementation (2 found)
    |
-LL |     <Impl1 as MyTrait2>::my_fn();
-   |     +++++++++         +
+LL |     </* self type */ as MyTrait2>::my_fn();
+   |     +++++++++++++++++++         +
 
 error: aborting due to 5 previous errors
 
-- 
cgit 1.4.1-3-g733a5