Rollup merge of #37370 - estebank:signature-2-empire-strikes-back, r=nikomatsakis

Include type of missing trait methods in error

Provide either a span pointing to the original definition of missing
trait items, or a message with the inferred definitions.

Fixes #24626. Follow up to PR #36371.

If PR #37369 lands, missing trait items that present a multiline span will be able to show the entirety of the item definition on the error itself, instead of just the first line.

10 files changed, 315 insertions, 0 deletions

diff --git a/src/test/ui/span/E0046.rs b/src/test/ui/span/E0046.rs
new file mode 100644
index 00000000000..9e757860a85
--- /dev/null
+++ b/src/test/ui/span/E0046.rs
@@ -0,0 +1,23 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+trait Foo {
+    fn foo();
+    //~^ NOTE `foo` from trait
+}
+
+struct Bar;
+
+impl Foo for Bar {}
+//~^ ERROR E0046
+//~| NOTE missing `foo` in implementation
+
+fn main() {
+}
diff --git a/src/test/ui/span/E0046.stderr b/src/test/ui/span/E0046.stderr
new file mode 100644
index 00000000000..729a5156124
--- /dev/null
+++ b/src/test/ui/span/E0046.stderr
@@ -0,0 +1,11 @@
+error[E0046]: not all trait items implemented, missing: `foo`
+  --> $DIR/E0046.rs:18:1
+   |
+12 |     fn foo();
+   |     --------- `foo` from trait
+...
+18 | impl Foo for Bar {}
+   | ^^^^^^^^^^^^^^^^^^^ missing `foo` in implementation
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/span/impl-wrong-item-for-trait.rs b/src/test/ui/span/impl-wrong-item-for-trait.rs
new file mode 100644
index 00000000000..54ed42af5d5
--- /dev/null
+++ b/src/test/ui/span/impl-wrong-item-for-trait.rs
@@ -0,0 +1,56 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(associated_consts)]
+
+use std::fmt::Debug;
+
+trait Foo {
+    fn bar(&self);
+    const MY_CONST: u32;
+}
+
+pub struct FooConstForMethod;
+
+impl Foo for FooConstForMethod {
+    //~^ ERROR E0046
+    //~| NOTE missing `bar` in implementation
+    const bar: u64 = 1;
+    //~^ ERROR E0323
+    //~| NOTE does not match trait
+    const MY_CONST: u32 = 1;
+}
+
+pub struct FooMethodForConst;
+
+impl Foo for FooMethodForConst {
+    //~^ ERROR E0046
+    //~| NOTE missing `MY_CONST` in implementation
+    fn bar(&self) {}
+    fn MY_CONST() {}
+    //~^ ERROR E0324
+    //~| NOTE does not match trait
+}
+
+pub struct FooTypeForMethod;
+
+impl Foo for FooTypeForMethod {
+    //~^ ERROR E0046
+    //~| NOTE missing `bar` in implementation
+    type bar = u64;
+    //~^ ERROR E0325
+    //~| NOTE does not match trait
+    const MY_CONST: u32 = 1;
+}
+
+impl Debug for FooTypeForMethod {
+}
+
+fn main () {}
diff --git a/src/test/ui/span/impl-wrong-item-for-trait.stderr b/src/test/ui/span/impl-wrong-item-for-trait.stderr
new file mode 100644
index 00000000000..244285e3584
--- /dev/null
+++ b/src/test/ui/span/impl-wrong-item-for-trait.stderr
@@ -0,0 +1,64 @@
+error[E0323]: item `bar` is an associated const, which doesn't match its trait `<FooConstForMethod as Foo>`
+  --> $DIR/impl-wrong-item-for-trait.rs:25:5
+   |
+16 |     fn bar(&self);
+   |     -------------- item in trait
+...
+25 |     const bar: u64 = 1;
+   |     ^^^^^^^^^^^^^^^^^^^ does not match trait
+
+error[E0046]: not all trait items implemented, missing: `bar`
+  --> $DIR/impl-wrong-item-for-trait.rs:22:1
+   |
+16 |     fn bar(&self);
+   |     -------------- `bar` from trait
+...
+22 | impl Foo for FooConstForMethod {
+   | ^ missing `bar` in implementation
+
+error[E0324]: item `MY_CONST` is an associated method, which doesn't match its trait `<FooMethodForConst as Foo>`
+  --> $DIR/impl-wrong-item-for-trait.rs:37:5
+   |
+17 |     const MY_CONST: u32;
+   |     -------------------- item in trait
+...
+37 |     fn MY_CONST() {}
+   |     ^^^^^^^^^^^^^^^^ does not match trait
+
+error[E0046]: not all trait items implemented, missing: `MY_CONST`
+  --> $DIR/impl-wrong-item-for-trait.rs:33:1
+   |
+17 |     const MY_CONST: u32;
+   |     -------------------- `MY_CONST` from trait
+...
+33 | impl Foo for FooMethodForConst {
+   | ^ missing `MY_CONST` in implementation
+
+error[E0325]: item `bar` is an associated type, which doesn't match its trait `<FooTypeForMethod as Foo>`
+  --> $DIR/impl-wrong-item-for-trait.rs:47:5
+   |
+16 |     fn bar(&self);
+   |     -------------- item in trait
+...
+47 |     type bar = u64;
+   |     ^^^^^^^^^^^^^^^ does not match trait
+
+error[E0046]: not all trait items implemented, missing: `bar`
+  --> $DIR/impl-wrong-item-for-trait.rs:44:1
+   |
+16 |     fn bar(&self);
+   |     -------------- `bar` from trait
+...
+44 | impl Foo for FooTypeForMethod {
+   | ^ missing `bar` in implementation
+
+error[E0046]: not all trait items implemented, missing: `fmt`
+  --> $DIR/impl-wrong-item-for-trait.rs:53:1
+   |
+53 | impl Debug for FooTypeForMethod {
+   | ^ missing `fmt` in implementation
+   |
+   = note: `fmt` from trait: `fn(&Self, &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error>`
+
+error: aborting due to 7 previous errors
+
diff --git a/src/test/ui/span/issue-23729.rs b/src/test/ui/span/issue-23729.rs
new file mode 100644
index 00000000000..66134a03baf
--- /dev/null
+++ b/src/test/ui/span/issue-23729.rs
@@ -0,0 +1,45 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Regression test for #23729
+
+fn main() {
+    let fib = {
+        struct Recurrence {
+            mem: [u64; 2],
+            pos: usize,
+        }
+
+        impl Iterator for Recurrence {
+            //~^ ERROR E0046
+            //~| NOTE missing `Item` in implementation
+            //~| NOTE `Item` from trait: `type Item;`
+            #[inline]
+            fn next(&mut self) -> Option<u64> {
+                if self.pos < 2 {
+                    let next_val = self.mem[self.pos];
+                    self.pos += 1;
+                    Some(next_val)
+                } else {
+                    let next_val = self.mem[0] + self.mem[1];
+                    self.mem[0] = self.mem[1];
+                    self.mem[1] = next_val;
+                    Some(next_val)
+                }
+            }
+        }
+
+        Recurrence { mem: [0, 1], pos: 0 }
+    };
+
+    for e in fib.take(10) {
+        println!("{}", e)
+    }
+}
diff --git a/src/test/ui/span/issue-23729.stderr b/src/test/ui/span/issue-23729.stderr
new file mode 100644
index 00000000000..493ca01778b
--- /dev/null
+++ b/src/test/ui/span/issue-23729.stderr
@@ -0,0 +1,10 @@
+error[E0046]: not all trait items implemented, missing: `Item`
+  --> $DIR/issue-23729.rs:20:9
+   |
+20 |         impl Iterator for Recurrence {
+   |         ^ missing `Item` in implementation
+   |
+   = note: `Item` from trait: `type Item;`
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/span/issue-23827.rs b/src/test/ui/span/issue-23827.rs
new file mode 100644
index 00000000000..a5ab443597b
--- /dev/null
+++ b/src/test/ui/span/issue-23827.rs
@@ -0,0 +1,45 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Regression test for #23827
+
+#![feature(core, unboxed_closures)]
+
+pub struct Prototype {
+    pub target: u32
+}
+
+trait Component {
+    fn apply(self, e: u32);
+}
+
+impl<C: Component> Fn<(C,)> for Prototype {
+    extern "rust-call" fn call(&self, (comp,): (C,)) -> Prototype {
+        comp.apply(self.target);
+        *self
+    }
+}
+
+impl<C: Component> FnMut<(C,)> for Prototype {
+    extern "rust-call" fn call_mut(&mut self, (comp,): (C,)) -> Prototype {
+        Fn::call(*&self, (comp,))
+    }
+}
+
+impl<C: Component> FnOnce<(C,)> for Prototype {
+    //~^ ERROR E0046
+    //~| NOTE missing `Output` in implementation
+    //~| NOTE `Output` from trait: `type Output;`
+    extern "rust-call" fn call_once(self, (comp,): (C,)) -> Prototype {
+        Fn::call(&self, (comp,))
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/span/issue-23827.stderr b/src/test/ui/span/issue-23827.stderr
new file mode 100644
index 00000000000..5130bb53a19
--- /dev/null
+++ b/src/test/ui/span/issue-23827.stderr
@@ -0,0 +1,10 @@
+error[E0046]: not all trait items implemented, missing: `Output`
+  --> $DIR/issue-23827.rs:36:1
+   |
+36 | impl<C: Component> FnOnce<(C,)> for Prototype {
+   | ^ missing `Output` in implementation
+   |
+   = note: `Output` from trait: `type Output;`
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/span/issue-24356.rs b/src/test/ui/span/issue-24356.rs
new file mode 100644
index 00000000000..0997dc802f8
--- /dev/null
+++ b/src/test/ui/span/issue-24356.rs
@@ -0,0 +1,41 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Regression test for #24356
+
+// ignore-tidy-linelength
+
+fn main() {
+    {
+        use std::ops::Deref;
+
+        struct Thing(i8);
+
+        /*
+        // Correct impl
+        impl Deref for Thing {
+            type Target = i8;
+            fn deref(&self) -> &i8 { &self.0 }
+        }
+        */
+
+        // Causes ICE
+        impl Deref for Thing {
+            //~^ ERROR E0046
+            //~| NOTE missing `Target` in implementation
+            //~| NOTE `Target` from trait: `type Target;`
+            fn deref(&self) -> i8 { self.0 }
+        }
+
+        let thing = Thing(72);
+
+        *thing
+    };
+}
diff --git a/src/test/ui/span/issue-24356.stderr b/src/test/ui/span/issue-24356.stderr
new file mode 100644
index 00000000000..906ef25ca0e
--- /dev/null
+++ b/src/test/ui/span/issue-24356.stderr
@@ -0,0 +1,10 @@
+error[E0046]: not all trait items implemented, missing: `Target`
+  --> $DIR/issue-24356.rs:30:9
+   |
+30 |         impl Deref for Thing {
+   |         ^ missing `Target` in implementation
+   |
+   = note: `Target` from trait: `type Target;`
+
+error: aborting due to previous error
+