Add more detail to type inference error

When encountering code where type inference fails, add more actionable
information:

```
fn main() {
    let foo = Vec::new();
}
```

```
error[E0282]: type annotations needed for `std::vec::Vec<_>`
  --> $DIR/vector-no-ann.rs:2:16
   |
LL |     let foo = Vec::new();
   |         ---   ^^^^^^^^ cannot infer type for `T`
   |         |
   |         consider giving `foo` the type `std::vec::Vec<_>` with the type parameter `T` specified
```

We still need to modify type printing to optionally accept a
`TypeVariableTable` in order to properly print `std::vec::Vec<T>`.

CC #25633.

9 files changed, 12 insertions, 12 deletions

diff --git a/src/test/ui/issues/issue-12187-1.rs b/src/test/ui/issues/issue-12187-1.rs
index 37ff468e032..86128ed94bd 100644
--- a/src/test/ui/issues/issue-12187-1.rs
+++ b/src/test/ui/issues/issue-12187-1.rs
@@ -4,5 +4,5 @@ fn new<T>() -> &'static T {
 
 fn main() {
     let &v = new();
-    //~^ ERROR type annotations needed [E0282]
+    //~^ ERROR type annotations needed
 }
diff --git a/src/test/ui/issues/issue-12187-1.stderr b/src/test/ui/issues/issue-12187-1.stderr
index f8df4f82e7e..77aa736873b 100644
--- a/src/test/ui/issues/issue-12187-1.stderr
+++ b/src/test/ui/issues/issue-12187-1.stderr
@@ -1,4 +1,4 @@
-error[E0282]: type annotations needed
+error[E0282]: type annotations needed for `&_`
   --> $DIR/issue-12187-1.rs:6:10
    |
 LL |     let &v = new();
diff --git a/src/test/ui/issues/issue-12187-2.rs b/src/test/ui/issues/issue-12187-2.rs
index a1cdb849779..080a6206be7 100644
--- a/src/test/ui/issues/issue-12187-2.rs
+++ b/src/test/ui/issues/issue-12187-2.rs
@@ -4,5 +4,5 @@ fn new<'r, T>() -> &'r T {
 
 fn main() {
     let &v = new();
-    //~^ ERROR type annotations needed [E0282]
+    //~^ ERROR type annotations needed
 }
diff --git a/src/test/ui/issues/issue-12187-2.stderr b/src/test/ui/issues/issue-12187-2.stderr
index c40ae0461ec..4953c2b11b5 100644
--- a/src/test/ui/issues/issue-12187-2.stderr
+++ b/src/test/ui/issues/issue-12187-2.stderr
@@ -1,4 +1,4 @@
-error[E0282]: type annotations needed
+error[E0282]: type annotations needed for `&_`
   --> $DIR/issue-12187-2.rs:6:10
    |
 LL |     let &v = new();
diff --git a/src/test/ui/issues/issue-17551.stderr b/src/test/ui/issues/issue-17551.stderr
index 40e7727752b..3e99d307b3b 100644
--- a/src/test/ui/issues/issue-17551.stderr
+++ b/src/test/ui/issues/issue-17551.stderr
@@ -1,10 +1,10 @@
-error[E0282]: type annotations needed
+error[E0282]: type annotations needed for `B<_>`
   --> $DIR/issue-17551.rs:6:15
    |
 LL |     let foo = B(marker::PhantomData);
    |         ---   ^ cannot infer type for `T`
    |         |
-   |         consider giving `foo` a type
+   |         consider giving `foo` the type `B<_>` with the type parameter `T` specified
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-20261.stderr b/src/test/ui/issues/issue-20261.stderr
index 5665f5893f4..c6c3f32dfe7 100644
--- a/src/test/ui/issues/issue-20261.stderr
+++ b/src/test/ui/issues/issue-20261.stderr
@@ -1,4 +1,4 @@
-error[E0282]: type annotations needed
+error[E0282]: type annotations needed for `&(_,)`
   --> $DIR/issue-20261.rs:4:11
    |
 LL |     for (ref i,) in [].iter() {
diff --git a/src/test/ui/issues/issue-23046.stderr b/src/test/ui/issues/issue-23046.stderr
index aab90a9d440..2ce77576404 100644
--- a/src/test/ui/issues/issue-23046.stderr
+++ b/src/test/ui/issues/issue-23046.stderr
@@ -1,8 +1,8 @@
-error[E0282]: type annotations needed
+error[E0282]: type annotations needed for `Expr<'_, _>`
   --> $DIR/issue-23046.rs:17:15
    |
 LL |     let ex = |x| {
-   |               ^ consider giving this closure parameter a type
+   |               ^ consider giving this closure parameter the type `Expr<'_, _>` with the type parameter `VAR` specified
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-25368.stderr b/src/test/ui/issues/issue-25368.stderr
index 3ad6a2569be..3b2c3bfe4ff 100644
--- a/src/test/ui/issues/issue-25368.stderr
+++ b/src/test/ui/issues/issue-25368.stderr
@@ -1,4 +1,4 @@
-error[E0282]: type annotations needed
+error[E0282]: type annotations needed for `(std::sync::mpsc::Sender<Foo<_>>, std::sync::mpsc::Receiver<Foo<_>>)`
   --> $DIR/issue-25368.rs:11:17
    |
 LL |     let (tx, rx) = channel();
diff --git a/src/test/ui/issues/issue-7813.stderr b/src/test/ui/issues/issue-7813.stderr
index 45b9c915885..8e2a69dd9e3 100644
--- a/src/test/ui/issues/issue-7813.stderr
+++ b/src/test/ui/issues/issue-7813.stderr
@@ -1,10 +1,10 @@
-error[E0282]: type annotations needed
+error[E0282]: type annotations needed for `&[_; 0]`
   --> $DIR/issue-7813.rs:2:13
    |
 LL |     let v = &[];
    |         -   ^^^ cannot infer type
    |         |
-   |         consider giving `v` a type
+   |         consider giving `v` the type `&[_; 0]` with the type parameter `_` specified
 
 error: aborting due to previous error