Point at overlapping impls when type annotations are needed

7 files changed, 228 insertions, 22 deletions

diff --git a/src/test/ui/issues/issue-29147.stderr b/src/test/ui/issues/issue-29147.stderr
index f00d5d32bbf..3b011f58b25 100644
--- a/src/test/ui/issues/issue-29147.stderr
+++ b/src/test/ui/issues/issue-29147.stderr
@@ -4,7 +4,13 @@ error[E0283]: type annotations needed
 LL |     let _ = <S5<_>>::xxx;
    |             ^^^^^^^^^^^^ cannot infer type for struct `S5<_>`
    |
-   = note: cannot satisfy `S5<_>: Foo`
+note: multiple `impl`s satisfying `S5<_>: Foo` found
+  --> $DIR/issue-29147.rs:17:1
+   |
+LL | impl Foo for S5<u32> { fn xxx(&self) {} }
+   | ^^^^^^^^^^^^^^^^^^^^
+LL | impl Foo for S5<u64> { fn xxx(&self) {} }
+   | ^^^^^^^^^^^^^^^^^^^^
 note: required by `Foo::xxx`
   --> $DIR/issue-29147.rs:10:13
    |
diff --git a/src/test/ui/issues/issue-69455.rs b/src/test/ui/issues/issue-69455.rs
index f1935ae2534..a53aadcfad0 100644
--- a/src/test/ui/issues/issue-69455.rs
+++ b/src/test/ui/issues/issue-69455.rs
@@ -27,4 +27,5 @@ impl Test<u64> for u64 {
 fn main() {
     let xs: Vec<u64> = vec![1, 2, 3];
     println!("{}", 23u64.test(xs.iter().sum())); //~ ERROR: type annotations needed
+    //~^ ERROR type annotations needed
 }
diff --git a/src/test/ui/issues/issue-69455.stderr b/src/test/ui/issues/issue-69455.stderr
index 430bbcabf83..da84a6b52da 100644
--- a/src/test/ui/issues/issue-69455.stderr
+++ b/src/test/ui/issues/issue-69455.stderr
@@ -4,6 +4,26 @@ error[E0284]: type annotations needed: cannot satisfy `<u64 as Test<_>>::Output
 LL |     println!("{}", 23u64.test(xs.iter().sum()));
    |                          ^^^^ cannot satisfy `<u64 as Test<_>>::Output == _`
 
-error: aborting due to previous error
+error[E0283]: type annotations needed
+  --> $DIR/issue-69455.rs:29:26
+   |
+LL |     println!("{}", 23u64.test(xs.iter().sum()));
+   |                          ^^^^ cannot infer type for type parameter `Rhs` declared on the trait `Test`
+   |
+note: multiple `impl`s satisfying `u64: Test<_>` found
+  --> $DIR/issue-69455.rs:11:1
+   |
+LL | impl Test<u32> for u64 {
+   | ^^^^^^^^^^^^^^^^^^^^^^
+...
+LL | impl Test<u64> for u64 {
+   | ^^^^^^^^^^^^^^^^^^^^^^
+help: consider specifying the type argument in the method call
+   |
+LL |     println!("{}", 23u64.test(xs.iter().sum::<S>()));
+   |                                            +++++
+
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0284`.
+Some errors have detailed explanations: E0283, E0284.
+For more information about an error, try `rustc --explain E0283`.
diff --git a/src/test/ui/issues/issue-69683.rs b/src/test/ui/issues/issue-69683.rs
index cc7f1fa0f55..7a76e9ef205 100644
--- a/src/test/ui/issues/issue-69683.rs
+++ b/src/test/ui/issues/issue-69683.rs
@@ -28,5 +28,6 @@ fn main() {
     let b: [u8; 3] = [0u8; 3];
 
     0u16.foo(b); //~ ERROR type annotations needed
+    //~^ ERROR type annotations needed
     //<u16 as Foo<[(); 3]>>::foo(0u16, b);
 }
diff --git a/src/test/ui/issues/issue-69683.stderr b/src/test/ui/issues/issue-69683.stderr
index 776370331a4..ecf78e48e0e 100644
--- a/src/test/ui/issues/issue-69683.stderr
+++ b/src/test/ui/issues/issue-69683.stderr
@@ -4,6 +4,22 @@ error[E0284]: type annotations needed: cannot satisfy `<u8 as Element<_>>::Array
 LL |     0u16.foo(b);
    |          ^^^ cannot satisfy `<u8 as Element<_>>::Array == [u8; 3]`
 
-error: aborting due to previous error
+error[E0283]: type annotations needed
+  --> $DIR/issue-69683.rs:30:10
+   |
+LL |     0u16.foo(b);
+   |          ^^^ cannot infer type for type parameter `I` declared on the trait `Foo`
+   |
+note: multiple `impl`s satisfying `u8: Element<_>` found
+  --> $DIR/issue-69683.rs:5:1
+   |
+LL | impl<T> Element<()> for T {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL | impl<T: Element<S>, S> Element<[S; 3]> for T {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0284`.
+Some errors have detailed explanations: E0283, E0284.
+For more information about an error, try `rustc --explain E0283`.
diff --git a/src/test/ui/issues/issue-72690.rs b/src/test/ui/issues/issue-72690.rs
index 4edbd9ca15d..916a7832c68 100644
--- a/src/test/ui/issues/issue-72690.rs
+++ b/src/test/ui/issues/issue-72690.rs
@@ -5,10 +5,13 @@ fn no_err() {
 
 fn err() {
     String::from("x".as_ref()); //~ ERROR type annotations needed
+    //~^ ERROR type annotations needed
 }
 
 fn arg_pat_closure_err() {
     |x| String::from("x".as_ref()); //~ ERROR type annotations needed
+    //~^ ERROR type annotations needed
+    //~| ERROR type annotations needed
 }
 
 fn local_pat_closure_err() {
@@ -17,12 +20,14 @@ fn local_pat_closure_err() {
 
 fn err_first_arg_pat() {
     String::from("x".as_ref()); //~ ERROR type annotations needed
+    //~^ ERROR type annotations needed
     |x: String| x;
 }
 
 fn err_second_arg_pat() {
     |x: String| x;
     String::from("x".as_ref()); //~ ERROR type annotations needed
+    //~^ ERROR type annotations needed
 }
 
 fn err_mid_arg_pat() {
@@ -31,6 +36,7 @@ fn err_mid_arg_pat() {
     |x: String| x;
     |x: String| x;
     String::from("x".as_ref()); //~ ERROR type annotations needed
+    //~^ ERROR type annotations needed
     |x: String| x;
     |x: String| x;
     |x: String| x;
@@ -39,12 +45,14 @@ fn err_mid_arg_pat() {
 
 fn err_first_local_pat() {
     String::from("x".as_ref()); //~ ERROR type annotations needed
+    //~^ ERROR type annotations needed
     let _ = String::from("x");
 }
 
 fn err_second_local_pat() {
     let _ = String::from("x");
     String::from("x".as_ref()); //~ ERROR type annotations needed
+    //~^ ERROR type annotations needed
 }
 
 fn err_mid_local_pat() {
@@ -53,6 +61,7 @@ fn err_mid_local_pat() {
     let _ = String::from("x");
     let _ = String::from("x");
     String::from("x".as_ref()); //~ ERROR type annotations needed
+    //~^ ERROR type annotations needed
     let _ = String::from("x");
     let _ = String::from("x");
     let _ = String::from("x");
diff --git a/src/test/ui/issues/issue-72690.stderr b/src/test/ui/issues/issue-72690.stderr
index af3459a7d2d..1747ca5bb04 100644
--- a/src/test/ui/issues/issue-72690.stderr
+++ b/src/test/ui/issues/issue-72690.stderr
@@ -4,36 +4,89 @@ error[E0283]: type annotations needed
 LL |     String::from("x".as_ref());
    |     ^^^^^^^^^^^^ cannot infer type for reference `&_`
    |
-   = note: cannot satisfy `String: From<&_>`
+   = note: multiple `impl`s satisfying `String: From<&_>` found in the `alloc` crate:
+           - impl<> From<&String> for String;
+           - impl<> From<&str> for String;
 note: required by `from`
   --> $SRC_DIR/core/src/convert/mod.rs:LL:COL
    |
 LL |     fn from(_: T) -> Self;
    |     ^^^^^^^^^^^^^^^^^^^^^^
 
+error[E0283]: type annotations needed
+  --> $DIR/issue-72690.rs:7:22
+   |
+LL |     String::from("x".as_ref());
+   |                  ----^^^^^^--
+   |                  |   |
+   |                  |   cannot infer type for type parameter `T` declared on the trait `AsRef`
+   |                  this method call resolves to `&T`
+   |
+   = note: multiple `impl`s satisfying `str: AsRef<_>` found in the following crates: `core`, `std`:
+           - impl AsRef<OsStr> for str;
+           - impl AsRef<Path> for str;
+           - impl AsRef<[u8]> for str;
+           - impl AsRef<str> for str;
+
 error[E0282]: type annotations needed
-  --> $DIR/issue-72690.rs:11:6
+  --> $DIR/issue-72690.rs:12:6
    |
 LL |     |x| String::from("x".as_ref());
    |      ^ consider giving this closure parameter a type
 
+error[E0283]: type annotations needed
+  --> $DIR/issue-72690.rs:12:9
+   |
+LL |     |x| String::from("x".as_ref());
+   |         ^^^^^^^^^^^^ cannot infer type for reference `&_`
+   |
+   = note: multiple `impl`s satisfying `String: From<&_>` found in the `alloc` crate:
+           - impl<> From<&String> for String;
+           - impl<> From<&str> for String;
+note: required by `from`
+  --> $SRC_DIR/core/src/convert/mod.rs:LL:COL
+   |
+LL |     fn from(_: T) -> Self;
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0283]: type annotations needed
+  --> $DIR/issue-72690.rs:12:26
+   |
+LL |     |x| String::from("x".as_ref());
+   |                      ----^^^^^^--
+   |                      |   |
+   |                      |   cannot infer type for type parameter `T` declared on the trait `AsRef`
+   |                      this method call resolves to `&T`
+   |
+   = note: multiple `impl`s satisfying `str: AsRef<_>` found in the following crates: `core`, `std`:
+           - impl AsRef<OsStr> for str;
+           - impl AsRef<Path> for str;
+           - impl AsRef<[u8]> for str;
+           - impl AsRef<str> for str;
+
 error[E0283]: type annotations needed for `&T`
-  --> $DIR/issue-72690.rs:15:17
+  --> $DIR/issue-72690.rs:18:17
    |
 LL |     let _ = "x".as_ref();
    |         -       ^^^^^^ cannot infer type for type parameter `T` declared on the trait `AsRef`
    |         |
    |         consider giving this pattern the explicit type `&T`, where the type parameter `T` is specified
    |
-   = note: cannot satisfy `str: AsRef<_>`
+   = note: multiple `impl`s satisfying `str: AsRef<_>` found in the following crates: `core`, `std`:
+           - impl AsRef<OsStr> for str;
+           - impl AsRef<Path> for str;
+           - impl AsRef<[u8]> for str;
+           - impl AsRef<str> for str;
 
 error[E0283]: type annotations needed
-  --> $DIR/issue-72690.rs:19:5
+  --> $DIR/issue-72690.rs:22:5
    |
 LL |     String::from("x".as_ref());
    |     ^^^^^^^^^^^^ cannot infer type for reference `&_`
    |
-   = note: cannot satisfy `String: From<&_>`
+   = note: multiple `impl`s satisfying `String: From<&_>` found in the `alloc` crate:
+           - impl<> From<&String> for String;
+           - impl<> From<&str> for String;
 note: required by `from`
   --> $SRC_DIR/core/src/convert/mod.rs:LL:COL
    |
@@ -41,12 +94,29 @@ LL |     fn from(_: T) -> Self;
    |     ^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0283]: type annotations needed
-  --> $DIR/issue-72690.rs:25:5
+  --> $DIR/issue-72690.rs:22:22
+   |
+LL |     String::from("x".as_ref());
+   |                  ----^^^^^^--
+   |                  |   |
+   |                  |   cannot infer type for type parameter `T` declared on the trait `AsRef`
+   |                  this method call resolves to `&T`
+   |
+   = note: multiple `impl`s satisfying `str: AsRef<_>` found in the following crates: `core`, `std`:
+           - impl AsRef<OsStr> for str;
+           - impl AsRef<Path> for str;
+           - impl AsRef<[u8]> for str;
+           - impl AsRef<str> for str;
+
+error[E0283]: type annotations needed
+  --> $DIR/issue-72690.rs:29:5
    |
 LL |     String::from("x".as_ref());
    |     ^^^^^^^^^^^^ cannot infer type for reference `&_`
    |
-   = note: cannot satisfy `String: From<&_>`
+   = note: multiple `impl`s satisfying `String: From<&_>` found in the `alloc` crate:
+           - impl<> From<&String> for String;
+           - impl<> From<&str> for String;
 note: required by `from`
   --> $SRC_DIR/core/src/convert/mod.rs:LL:COL
    |
@@ -54,12 +124,29 @@ LL |     fn from(_: T) -> Self;
    |     ^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0283]: type annotations needed
-  --> $DIR/issue-72690.rs:33:5
+  --> $DIR/issue-72690.rs:29:22
+   |
+LL |     String::from("x".as_ref());
+   |                  ----^^^^^^--
+   |                  |   |
+   |                  |   cannot infer type for type parameter `T` declared on the trait `AsRef`
+   |                  this method call resolves to `&T`
+   |
+   = note: multiple `impl`s satisfying `str: AsRef<_>` found in the following crates: `core`, `std`:
+           - impl AsRef<OsStr> for str;
+           - impl AsRef<Path> for str;
+           - impl AsRef<[u8]> for str;
+           - impl AsRef<str> for str;
+
+error[E0283]: type annotations needed
+  --> $DIR/issue-72690.rs:38:5
    |
 LL |     String::from("x".as_ref());
    |     ^^^^^^^^^^^^ cannot infer type for reference `&_`
    |
-   = note: cannot satisfy `String: From<&_>`
+   = note: multiple `impl`s satisfying `String: From<&_>` found in the `alloc` crate:
+           - impl<> From<&String> for String;
+           - impl<> From<&str> for String;
 note: required by `from`
   --> $SRC_DIR/core/src/convert/mod.rs:LL:COL
    |
@@ -67,12 +154,29 @@ LL |     fn from(_: T) -> Self;
    |     ^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0283]: type annotations needed
-  --> $DIR/issue-72690.rs:41:5
+  --> $DIR/issue-72690.rs:38:22
+   |
+LL |     String::from("x".as_ref());
+   |                  ----^^^^^^--
+   |                  |   |
+   |                  |   cannot infer type for type parameter `T` declared on the trait `AsRef`
+   |                  this method call resolves to `&T`
+   |
+   = note: multiple `impl`s satisfying `str: AsRef<_>` found in the following crates: `core`, `std`:
+           - impl AsRef<OsStr> for str;
+           - impl AsRef<Path> for str;
+           - impl AsRef<[u8]> for str;
+           - impl AsRef<str> for str;
+
+error[E0283]: type annotations needed
+  --> $DIR/issue-72690.rs:47:5
    |
 LL |     String::from("x".as_ref());
    |     ^^^^^^^^^^^^ cannot infer type for reference `&_`
    |
-   = note: cannot satisfy `String: From<&_>`
+   = note: multiple `impl`s satisfying `String: From<&_>` found in the `alloc` crate:
+           - impl<> From<&String> for String;
+           - impl<> From<&str> for String;
 note: required by `from`
   --> $SRC_DIR/core/src/convert/mod.rs:LL:COL
    |
@@ -80,12 +184,29 @@ LL |     fn from(_: T) -> Self;
    |     ^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0283]: type annotations needed
-  --> $DIR/issue-72690.rs:47:5
+  --> $DIR/issue-72690.rs:47:22
+   |
+LL |     String::from("x".as_ref());
+   |                  ----^^^^^^--
+   |                  |   |
+   |                  |   cannot infer type for type parameter `T` declared on the trait `AsRef`
+   |                  this method call resolves to `&T`
+   |
+   = note: multiple `impl`s satisfying `str: AsRef<_>` found in the following crates: `core`, `std`:
+           - impl AsRef<OsStr> for str;
+           - impl AsRef<Path> for str;
+           - impl AsRef<[u8]> for str;
+           - impl AsRef<str> for str;
+
+error[E0283]: type annotations needed
+  --> $DIR/issue-72690.rs:54:5
    |
 LL |     String::from("x".as_ref());
    |     ^^^^^^^^^^^^ cannot infer type for reference `&_`
    |
-   = note: cannot satisfy `String: From<&_>`
+   = note: multiple `impl`s satisfying `String: From<&_>` found in the `alloc` crate:
+           - impl<> From<&String> for String;
+           - impl<> From<&str> for String;
 note: required by `from`
   --> $SRC_DIR/core/src/convert/mod.rs:LL:COL
    |
@@ -93,19 +214,51 @@ LL |     fn from(_: T) -> Self;
    |     ^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0283]: type annotations needed
-  --> $DIR/issue-72690.rs:55:5
+  --> $DIR/issue-72690.rs:54:22
+   |
+LL |     String::from("x".as_ref());
+   |                  ----^^^^^^--
+   |                  |   |
+   |                  |   cannot infer type for type parameter `T` declared on the trait `AsRef`
+   |                  this method call resolves to `&T`
+   |
+   = note: multiple `impl`s satisfying `str: AsRef<_>` found in the following crates: `core`, `std`:
+           - impl AsRef<OsStr> for str;
+           - impl AsRef<Path> for str;
+           - impl AsRef<[u8]> for str;
+           - impl AsRef<str> for str;
+
+error[E0283]: type annotations needed
+  --> $DIR/issue-72690.rs:63:5
    |
 LL |     String::from("x".as_ref());
    |     ^^^^^^^^^^^^ cannot infer type for reference `&_`
    |
-   = note: cannot satisfy `String: From<&_>`
+   = note: multiple `impl`s satisfying `String: From<&_>` found in the `alloc` crate:
+           - impl<> From<&String> for String;
+           - impl<> From<&str> for String;
 note: required by `from`
   --> $SRC_DIR/core/src/convert/mod.rs:LL:COL
    |
 LL |     fn from(_: T) -> Self;
    |     ^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 9 previous errors
+error[E0283]: type annotations needed
+  --> $DIR/issue-72690.rs:63:22
+   |
+LL |     String::from("x".as_ref());
+   |                  ----^^^^^^--
+   |                  |   |
+   |                  |   cannot infer type for type parameter `T` declared on the trait `AsRef`
+   |                  this method call resolves to `&T`
+   |
+   = note: multiple `impl`s satisfying `str: AsRef<_>` found in the following crates: `core`, `std`:
+           - impl AsRef<OsStr> for str;
+           - impl AsRef<Path> for str;
+           - impl AsRef<[u8]> for str;
+           - impl AsRef<str> for str;
+
+error: aborting due to 18 previous errors
 
 Some errors have detailed explanations: E0282, E0283.
 For more information about an error, try `rustc --explain E0282`.