6 files changed, 123 insertions, 0 deletions
diff --git a/src/test/ui/derived-errors/issue-30580.rs b/src/test/ui/derived-errors/issue-30580.rs
new file mode 100644
index 000000000..6940fcf7c
--- /dev/null
+++ b/src/test/ui/derived-errors/issue-30580.rs
@@ -0,0 +1,17 @@
+// Test that we do not see uninformative region-related errors
+// when we get some basic type-checking failure. See #30580.
+
+pub struct Foo { a: u32 }
+pub struct Pass<'a, 'tcx: 'a>(&'a mut &'a (), &'a &'tcx ());
+
+impl<'a, 'tcx> Pass<'a, 'tcx>
+{
+    pub fn tcx(&self) -> &'a &'tcx () { self.1 }
+    fn lol(&mut self, b: &Foo)
+    {
+        b.c; //~ ERROR no field `c` on type `&Foo`
+        self.tcx();
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/derived-errors/issue-30580.stderr b/src/test/ui/derived-errors/issue-30580.stderr
new file mode 100644
index 000000000..7bd0eaf77
--- /dev/null
+++ b/src/test/ui/derived-errors/issue-30580.stderr
@@ -0,0 +1,9 @@
+error[E0609]: no field `c` on type `&Foo`
+  --> $DIR/issue-30580.rs:12:11
+   |
+LL |         b.c;
+   |           ^ help: a field with a similar name exists: `a`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0609`.
diff --git a/src/test/ui/derived-errors/issue-31997-1.rs b/src/test/ui/derived-errors/issue-31997-1.rs
new file mode 100644
index 000000000..90c1b498c
--- /dev/null
+++ b/src/test/ui/derived-errors/issue-31997-1.rs
@@ -0,0 +1,56 @@
+// Regression test for this example from #31997 -- main goal is to
+// emit as minimal and precise an error set as possible. Ideally, we'd
+// only emit the E0433 error below, but right now we emit two.
+
+use std::io::prelude::*;
+// use std::collections::HashMap;
+use std::io;
+
+#[derive(Debug)]
+struct Instance {
+    name: String,
+    start: Option<String>,
+    end: Option<String>,
+}
+
+fn main() {
+    let input = io::stdin();
+    let mut input = input.lock();
+
+    let mut map = HashMap::new();
+    //~^ ERROR E0433
+
+    for line in input.lines() {
+        let line = line.unwrap();
+        println!("process: {}", line);
+        let mut parts = line.splitn(2, ":");
+        let _logfile = parts.next().unwrap();
+        let rest = parts.next().unwrap();
+        let mut parts = line.split(" [-] ");
+
+        let stamp = parts.next().unwrap();
+
+        let rest = parts.next().unwrap();
+        let words = rest.split_whitespace().collect::<Vec<_>>();
+
+        let instance = words.iter().find(|a| a.starts_with("i-")).unwrap();
+        let name = words[1].to_owned();
+        let mut entry = map.entry(instance.to_owned()).or_insert(Instance {
+            name: name,
+            start: None,
+            end: None,
+        });
+
+        if rest.contains("terminating") {
+            assert!(entry.end.is_none());
+            entry.end = Some(stamp.to_string());
+        }
+        if rest.contains("waiting for") {
+            assert!(entry.start.is_none());
+            entry.start = Some(stamp.to_string());
+        }
+
+    }
+
+    println!("{:?}", map);
+}
diff --git a/src/test/ui/derived-errors/issue-31997-1.stderr b/src/test/ui/derived-errors/issue-31997-1.stderr
new file mode 100644
index 000000000..6d177666e
--- /dev/null
+++ b/src/test/ui/derived-errors/issue-31997-1.stderr
@@ -0,0 +1,14 @@
+error[E0433]: failed to resolve: use of undeclared type `HashMap`
+  --> $DIR/issue-31997-1.rs:20:19
+   |
+LL |     let mut map = HashMap::new();
+   |                   ^^^^^^^ not found in this scope
+   |
+help: consider importing this struct
+   |
+LL | use std::collections::HashMap;
+   |
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0433`.
diff --git a/src/test/ui/derived-errors/issue-31997.rs b/src/test/ui/derived-errors/issue-31997.rs
new file mode 100644
index 000000000..ff619313a
--- /dev/null
+++ b/src/test/ui/derived-errors/issue-31997.rs
@@ -0,0 +1,18 @@
+// Test that the resolve failure does not lead to downstream type errors.
+// See issue #31997.
+#![allow(deprecated)]
+
+trait TheTrait { }
+
+fn closure<F, T>(x: F) -> Result<T, ()>
+    where F: FnMut() -> T, T: TheTrait,
+{
+    unimplemented!()
+}
+
+fn foo() -> Result<(), ()> {
+    try!(closure(|| bar(core::ptr::null_mut()))); //~ ERROR cannot find function `bar` in this scope
+    Ok(())
+}
+
+fn main() { }
diff --git a/src/test/ui/derived-errors/issue-31997.stderr b/src/test/ui/derived-errors/issue-31997.stderr
new file mode 100644
index 000000000..b53c0cda8
--- /dev/null
+++ b/src/test/ui/derived-errors/issue-31997.stderr
@@ -0,0 +1,9 @@
+error[E0425]: cannot find function `bar` in this scope
+  --> $DIR/issue-31997.rs:14:21
+   |
+LL |     try!(closure(|| bar(core::ptr::null_mut())));
+   |                     ^^^ not found in this scope
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0425`.