tests failing in git master branch on consecutive "cargo test"s

[matthiaskrgr]

meta:

git repo @ b7a0b97e97e1aa9e7ce2377ae623cbbdaf78372c
rustc 1.26.0-nightly (ae544ee1c 2018-03-29)

I was trying to do some changes to clippy but the testsuit already failed without me doing anything :(
some failures:

test [ui] ui/regex.rs ... FAILED
test [ui] ui/serde.rs ... FAILED
test [ui] ui/useless_attribute.rs ... FAILED

failures:
---- [ui] ui/regex.rs stdout ----
    normalized stderr:
error[E0464]: multiple matching crates for `regex`
 --> $DIR/regex.rs:7:1
  |
7 | extern crate regex;
  | ^^^^^^^^^^^^^^^^^^^
  |
  = note: candidates:
          crate `regex`: /home/matthias/rust-clippy/target/debug/deps/libregex-675feed4e989e2c7.rlib
error[E0514]: found crate `regex` compiled by an incompatible version of rustc
 --> $DIR/regex.rs:7:1
  |
7 | extern crate regex;
  | ^^^^^^^^^^^^^^^^^^^
  |
  = help: please recompile that crate using this compiler (rustc 1.26.0-nightly (ae544ee1c 2018-03-29))
  = note: the following crate versions were found:
          crate `regex` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libregex_syntax-545ef797e48b20ad.rlib
          crate `regex` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libregex-4ccd5a559b909c15.rlib
error: aborting due to 2 previous errors
Some errors occurred: E0464, E0514.
For more information about an error, try `rustc --explain E0464`.
expected stderr:
error: trivial regex
  --> $DIR/regex.rs:16:45
   |
16 |     let pipe_in_wrong_position = Regex::new("|");
   |                                             ^^^
   |
   = note: `-D trivial-regex` implied by `-D warnings`
   = help: the regex is unlikely to be useful as it is
error: trivial regex
  --> $DIR/regex.rs:17:60
   |
17 |     let pipe_in_wrong_position_builder = RegexBuilder::new("|");
   |                                                            ^^^
   |
   = help: the regex is unlikely to be useful as it is
error: regex syntax error: invalid character class range, the start must be <= the end
  --> $DIR/regex.rs:18:42
   |
18 |     let wrong_char_ranice = Regex::new("[z-a]");
   |                                          ^^^
   |
   = note: `-D invalid-regex` implied by `-D warnings`
error: regex syntax error: invalid character class range, the start must be <= the end
  --> $DIR/regex.rs:19:37
   |
19 |     let some_unicode = Regex::new("[é-è]");
   |                                     ^^^
error: regex syntax error on position 0: unclosed group
  --> $DIR/regex.rs:21:33
   |
21 |     let some_regex = Regex::new(OPENING_PAREN);
   |                                 ^^^^^^^^^^^^^
error: trivial regex
  --> $DIR/regex.rs:23:53
   |
23 |     let binary_pipe_in_wrong_position = BRegex::new("|");
   |                                                     ^^^
   |
   = help: the regex is unlikely to be useful as it is
error: regex syntax error on position 0: unclosed group
  --> $DIR/regex.rs:24:41
   |
24 |     let some_binary_regex = BRegex::new(OPENING_PAREN);
   |                                         ^^^^^^^^^^^^^
error: regex syntax error on position 0: unclosed group
  --> $DIR/regex.rs:25:56
   |
25 |     let some_binary_regex_builder = BRegexBuilder::new(OPENING_PAREN);
   |                                                        ^^^^^^^^^^^^^
error: regex syntax error on position 0: unclosed group
  --> $DIR/regex.rs:40:9
   |
40 |         OPENING_PAREN,
   |         ^^^^^^^^^^^^^
error: regex syntax error on position 0: unclosed group
  --> $DIR/regex.rs:44:9
   |
44 |         OPENING_PAREN,
   |         ^^^^^^^^^^^^^
error: regex syntax error: unrecognized escape sequence
  --> $DIR/regex.rs:48:45
   |
48 |     let raw_string_error = Regex::new(r"[...//...]");
   |                                             ^^
error: regex syntax error: unrecognized escape sequence
  --> $DIR/regex.rs:49:46
   |
49 |     let raw_string_error = Regex::new(r#"[...//...]"#);
   |                                              ^^
error: trivial regex
  --> $DIR/regex.rs:53:33
   |
53 |     let trivial_eq = Regex::new("^foobar$");
   |                                 ^^^^^^^^^^
   |
   = help: consider using `==` on `str`s
error: trivial regex
  --> $DIR/regex.rs:55:48
   |
55 |     let trivial_eq_builder = RegexBuilder::new("^foobar$");
   |                                                ^^^^^^^^^^
   |
   = help: consider using `==` on `str`s
error: trivial regex
  --> $DIR/regex.rs:57:42
   |
57 |     let trivial_starts_with = Regex::new("^foobar");
   |                                          ^^^^^^^^^
   |
   = help: consider using `str::starts_with`
error: trivial regex
  --> $DIR/regex.rs:59:40
   |
59 |     let trivial_ends_with = Regex::new("foobar$");
   |                                        ^^^^^^^^^
   |
   = help: consider using `str::ends_with`
error: trivial regex
  --> $DIR/regex.rs:61:39
   |
61 |     let trivial_contains = Regex::new("foobar");
   |                                       ^^^^^^^^
   |
   = help: consider using `str::contains`
error: trivial regex
  --> $DIR/regex.rs:63:39
   |
63 |     let trivial_contains = Regex::new(NOT_A_REAL_REGEX);
   |                                       ^^^^^^^^^^^^^^^^
   |
   = help: consider using `str::contains`
error: trivial regex
  --> $DIR/regex.rs:65:40
   |
65 |     let trivial_backslash = Regex::new("a/.b");
   |                                        ^^^^^^^
   |
   = help: consider using `str::contains`
error: trivial regex
  --> $DIR/regex.rs:68:36
   |
68 |     let trivial_empty = Regex::new("");
   |                                    ^^
   |
   = help: the regex is unlikely to be useful as it is
error: trivial regex
  --> $DIR/regex.rs:70:36
   |
70 |     let trivial_empty = Regex::new("^");
   |                                    ^^^
   |
   = help: the regex is unlikely to be useful as it is
error: trivial regex
  --> $DIR/regex.rs:72:36
   |
72 |     let trivial_empty = Regex::new("^$");
   |                                    ^^^^
   |
   = help: consider using `str::is_empty`
error: trivial regex
  --> $DIR/regex.rs:74:44
   |
74 |     let binary_trivial_empty = BRegex::new("^$");
   |                                            ^^^^
   |
   = help: consider using `str::is_empty`
error: aborting due to 23 previous errors
diff of stderr:
-error: trivial regex
-  --> $DIR/regex.rs:16:45
-   |
-16 |     let pipe_in_wrong_position = Regex::new("|");
-   |                                             ^^^
-   |
-   = note: `-D trivial-regex` implied by `-D warnings`
-   = help: the regex is unlikely to be useful as it is
+error[E0464]: multiple matching crates for `regex`
+ --> $DIR/regex.rs:7:1
+  |
+7 | extern crate regex;
+  | ^^^^^^^^^^^^^^^^^^^
+  |
+  = note: candidates:
+          crate `regex`: /home/matthias/rust-clippy/target/debug/deps/libregex-675feed4e989e2c7.rlib
-error: trivial regex
-  --> $DIR/regex.rs:17:60
-   |
-17 |     let pipe_in_wrong_position_builder = RegexBuilder::new("|");
-   |                                                            ^^^
-   |
-   = help: the regex is unlikely to be useful as it is
+error[E0514]: found crate `regex` compiled by an incompatible version of rustc
+ --> $DIR/regex.rs:7:1
+  |
+7 | extern crate regex;
+  | ^^^^^^^^^^^^^^^^^^^
+  |
+  = help: please recompile that crate using this compiler (rustc 1.26.0-nightly (ae544ee1c 2018-03-29))
+  = note: the following crate versions were found:
+          crate `regex` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libregex_syntax-545ef797e48b20ad.rlib
+          crate `regex` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libregex-4ccd5a559b909c15.rlib
-error: regex syntax error: invalid character class range, the start must be <= the end
-  --> $DIR/regex.rs:18:42
-   |
-18 |     let wrong_char_ranice = Regex::new("[z-a]");
-   |                                          ^^^
-   |
-   = note: `-D invalid-regex` implied by `-D warnings`
+error: aborting due to 2 previous errors
-error: regex syntax error: invalid character class range, the start must be <= the end
-  --> $DIR/regex.rs:19:37
-   |
-19 |     let some_unicode = Regex::new("[é-è]");
-   |                                     ^^^
-
-error: regex syntax error on position 0: unclosed group
-  --> $DIR/regex.rs:21:33
-   |
-21 |     let some_regex = Regex::new(OPENING_PAREN);
-   |                                 ^^^^^^^^^^^^^
-
-error: trivial regex
-  --> $DIR/regex.rs:23:53
-   |
-23 |     let binary_pipe_in_wrong_position = BRegex::new("|");
-   |                                                     ^^^
-   |
-   = help: the regex is unlikely to be useful as it is
-
-error: regex syntax error on position 0: unclosed group
-  --> $DIR/regex.rs:24:41
-   |
-24 |     let some_binary_regex = BRegex::new(OPENING_PAREN);
-   |                                         ^^^^^^^^^^^^^
-
-error: regex syntax error on position 0: unclosed group
-  --> $DIR/regex.rs:25:56
-   |
-25 |     let some_binary_regex_builder = BRegexBuilder::new(OPENING_PAREN);
-   |                                                        ^^^^^^^^^^^^^
-
-error: regex syntax error on position 0: unclosed group
-  --> $DIR/regex.rs:40:9
-   |
-40 |         OPENING_PAREN,
-   |         ^^^^^^^^^^^^^
-
-error: regex syntax error on position 0: unclosed group
-  --> $DIR/regex.rs:44:9
-   |
-44 |         OPENING_PAREN,
-   |         ^^^^^^^^^^^^^
-
-error: regex syntax error: unrecognized escape sequence
-  --> $DIR/regex.rs:48:45
-   |
-48 |     let raw_string_error = Regex::new(r"[...//...]");
-   |                                             ^^
-
-error: regex syntax error: unrecognized escape sequence
-  --> $DIR/regex.rs:49:46
-   |
-49 |     let raw_string_error = Regex::new(r#"[...//...]"#);
-   |                                              ^^
-
-error: trivial regex
-  --> $DIR/regex.rs:53:33
-   |
-53 |     let trivial_eq = Regex::new("^foobar$");
-   |                                 ^^^^^^^^^^
-   |
-   = help: consider using `==` on `str`s
-
-error: trivial regex
-  --> $DIR/regex.rs:55:48
-   |
-55 |     let trivial_eq_builder = RegexBuilder::new("^foobar$");
-   |                                                ^^^^^^^^^^
-   |
-   = help: consider using `==` on `str`s
-
-error: trivial regex
-  --> $DIR/regex.rs:57:42
-   |
-57 |     let trivial_starts_with = Regex::new("^foobar");
-   |                                          ^^^^^^^^^
-   |
-   = help: consider using `str::starts_with`
-
-error: trivial regex
-  --> $DIR/regex.rs:59:40
-   |
-59 |     let trivial_ends_with = Regex::new("foobar$");
-   |                                        ^^^^^^^^^
-   |
-   = help: consider using `str::ends_with`
-
-error: trivial regex
-  --> $DIR/regex.rs:61:39
-   |
-61 |     let trivial_contains = Regex::new("foobar");
-   |                                       ^^^^^^^^
-   |
-   = help: consider using `str::contains`
-
-error: trivial regex
-  --> $DIR/regex.rs:63:39
-   |
-63 |     let trivial_contains = Regex::new(NOT_A_REAL_REGEX);
-   |                                       ^^^^^^^^^^^^^^^^
-   |
-   = help: consider using `str::contains`
-
-error: trivial regex
-  --> $DIR/regex.rs:65:40
-   |
-65 |     let trivial_backslash = Regex::new("a/.b");
-   |                                        ^^^^^^^
-   |
-   = help: consider using `str::contains`
-
-error: trivial regex
-  --> $DIR/regex.rs:68:36
-   |
-68 |     let trivial_empty = Regex::new("");
-   |                                    ^^
-   |
-   = help: the regex is unlikely to be useful as it is
-
-error: trivial regex
-  --> $DIR/regex.rs:70:36
-   |
-70 |     let trivial_empty = Regex::new("^");
-   |                                    ^^^
-   |
-   = help: the regex is unlikely to be useful as it is
-
-error: trivial regex
-  --> $DIR/regex.rs:72:36
-   |
-72 |     let trivial_empty = Regex::new("^$");
-   |                                    ^^^^
-   |
-   = help: consider using `str::is_empty`
-
-error: trivial regex
-  --> $DIR/regex.rs:74:44
-   |
-74 |     let binary_trivial_empty = BRegex::new("^$");
-   |                                            ^^^^
-   |
-   = help: consider using `str::is_empty`
-
-error: aborting due to 23 previous errors
-
+Some errors occurred: E0464, E0514.
+For more information about an error, try `rustc --explain E0464`.
The actual stderr differed from the expected stderr.
Actual stderr saved to /home/matthias/rust-clippy/target/debug/test_build_base/regex.stderr
To update references, run this command from build directory:
tests/ui/update-references.sh '/home/matthias/rust-clippy/target/debug/test_build_base' 'regex.rs'
error: 1 errors occurred comparing output.
status: exit code: 101
command: "target/debug/clippy-driver" "tests/ui/regex.rs" "-L" "/home/matthias/rust-clippy/target/debug/test_build_base" "--target=x86_64-unknown-linux-gnu" "-C" "prefer-dynamic" "-o" "/home/matthias/rust-clippy/target/debug/test_build_base/regex.stage-id" "-L" "target/debug" "-L" "target/debug/deps" "-Dwarnings" "-L" "/home/matthias/rust-clippy/target/debug/test_build_base/regex.stage-id.aux" "-A" "unused"
stdout:
------------------------------------------
------------------------------------------
stderr:
------------------------------------------
error[E0464]: multiple matching crates for `regex`
 --> tests/ui/regex.rs:7:1
  |
7 | extern crate regex;
  | ^^^^^^^^^^^^^^^^^^^
  |
  = note: candidates:
          crate `regex`: /home/matthias/rust-clippy/target/debug/deps/libregex-675feed4e989e2c7.rlib
error[E0514]: found crate `regex` compiled by an incompatible version of rustc
 --> tests/ui/regex.rs:7:1
  |
7 | extern crate regex;
  | ^^^^^^^^^^^^^^^^^^^
  |
  = help: please recompile that crate using this compiler (rustc 1.26.0-nightly (ae544ee1c 2018-03-29))
  = note: the following crate versions were found:
          crate `regex` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libregex_syntax-545ef797e48b20ad.rlib
          crate `regex` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libregex-4ccd5a559b909c15.rlib
error: aborting due to 2 previous errors
Some errors occurred: E0464, E0514.
For more information about an error, try `rustc --explain E0464`.
------------------------------------------
thread '[ui] ui/regex.rs' panicked at 'explicit panic', /home/matthias/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/compiletest_rs-0.3.9/src/runtest.rs:2539:9
note: Run with `RUST_BACKTRACE=1` for a backtrace.
---- [ui] ui/serde.rs stdout ----
    normalized stderr:
error[E0464]: multiple matching crates for `serde`
 --> $DIR/serde.rs:6:1
  |
6 | extern crate serde;
  | ^^^^^^^^^^^^^^^^^^^
  |
  = note: candidates:
          crate `serde`: /home/matthias/rust-clippy/target/debug/deps/libserde-d18100ee91b3640a.rlib
error[E0514]: found crate `serde` compiled by an incompatible version of rustc
 --> $DIR/serde.rs:6:1
  |
6 | extern crate serde;
  | ^^^^^^^^^^^^^^^^^^^
  |
  = help: please recompile that crate using this compiler (rustc 1.26.0-nightly (ae544ee1c 2018-03-29))
  = note: the following crate versions were found:
          crate `serde` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libserde_json-db7e52ba9e91e774.rlib
          crate `serde` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libserde_derive-41da0132bcc3c37d.so
          crate `serde` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libserde_derive_internals-7fc8ef425398707f.rlib
          crate `serde` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libserde-a08a2b6beca6b10b.rlib
error: aborting due to 2 previous errors
Some errors occurred: E0464, E0514.
For more information about an error, try `rustc --explain E0464`.
expected stderr:
error: you should not implement `visit_string` without also implementing `visit_str`
  --> $DIR/serde.rs:39:5
   |
39 | /     fn visit_string<E>(self, _v: String) -> Result<Self::Value, E>
40 | |         where E: serde::de::Error,
41 | |     {
42 | |         unimplemented!()
43 | |     }
   | |_____^
   |
   = note: `-D serde-api-misuse` implied by `-D warnings`
error: aborting due to previous error
diff of stderr:
-error: you should not implement `visit_string` without also implementing `visit_str`
-  --> $DIR/serde.rs:39:5
-   |
-39 | /     fn visit_string<E>(self, _v: String) -> Result<Self::Value, E>
-40 | |         where E: serde::de::Error,
-41 | |     {
-42 | |         unimplemented!()
-43 | |     }
-   | |_____^
-   |
-   = note: `-D serde-api-misuse` implied by `-D warnings`
+error[E0464]: multiple matching crates for `serde`
+ --> $DIR/serde.rs:6:1
+  |
+6 | extern crate serde;
+  | ^^^^^^^^^^^^^^^^^^^
+  |
+  = note: candidates:
+          crate `serde`: /home/matthias/rust-clippy/target/debug/deps/libserde-d18100ee91b3640a.rlib
-error: aborting due to previous error
+error[E0514]: found crate `serde` compiled by an incompatible version of rustc
+ --> $DIR/serde.rs:6:1
+  |
+6 | extern crate serde;
+  | ^^^^^^^^^^^^^^^^^^^
+  |
+  = help: please recompile that crate using this compiler (rustc 1.26.0-nightly (ae544ee1c 2018-03-29))
+  = note: the following crate versions were found:
+          crate `serde` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libserde_json-db7e52ba9e91e774.rlib
+          crate `serde` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libserde_derive-41da0132bcc3c37d.so
+          crate `serde` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libserde_derive_internals-7fc8ef425398707f.rlib
+          crate `serde` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libserde-a08a2b6beca6b10b.rlib
+error: aborting due to 2 previous errors
+
+Some errors occurred: E0464, E0514.
+For more information about an error, try `rustc --explain E0464`.
The actual stderr differed from the expected stderr.
Actual stderr saved to /home/matthias/rust-clippy/target/debug/test_build_base/serde.stderr
To update references, run this command from build directory:
tests/ui/update-references.sh '/home/matthias/rust-clippy/target/debug/test_build_base' 'serde.rs'
error: 1 errors occurred comparing output.
status: exit code: 101
command: "target/debug/clippy-driver" "tests/ui/serde.rs" "-L" "/home/matthias/rust-clippy/target/debug/test_build_base" "--target=x86_64-unknown-linux-gnu" "-C" "prefer-dynamic" "-o" "/home/matthias/rust-clippy/target/debug/test_build_base/serde.stage-id" "-L" "target/debug" "-L" "target/debug/deps" "-Dwarnings" "-L" "/home/matthias/rust-clippy/target/debug/test_build_base/serde.stage-id.aux" "-A" "unused"
stdout:
------------------------------------------
------------------------------------------
stderr:
------------------------------------------
error[E0464]: multiple matching crates for `serde`
 --> tests/ui/serde.rs:6:1
  |
6 | extern crate serde;
  | ^^^^^^^^^^^^^^^^^^^
  |
  = note: candidates:
          crate `serde`: /home/matthias/rust-clippy/target/debug/deps/libserde-d18100ee91b3640a.rlib
error[E0514]: found crate `serde` compiled by an incompatible version of rustc
 --> tests/ui/serde.rs:6:1
  |
6 | extern crate serde;
  | ^^^^^^^^^^^^^^^^^^^
  |
  = help: please recompile that crate using this compiler (rustc 1.26.0-nightly (ae544ee1c 2018-03-29))
  = note: the following crate versions were found:
          crate `serde` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libserde_json-db7e52ba9e91e774.rlib
          crate `serde` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libserde_derive-41da0132bcc3c37d.so
          crate `serde` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libserde_derive_internals-7fc8ef425398707f.rlib
          crate `serde` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libserde-a08a2b6beca6b10b.rlib
error: aborting due to 2 previous errors
Some errors occurred: E0464, E0514.
For more information about an error, try `rustc --explain E0464`.
------------------------------------------
thread '[ui] ui/serde.rs' panicked at 'explicit panic', /home/matthias/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/compiletest_rs-0.3.9/src/runtest.rs:2539:9
---- [ui] ui/useless_attribute.rs stdout ----
    normalized stderr:
error[E0464]: multiple matching crates for `clippy_lints`
 --> $DIR/useless_attribute.rs:9:1
  |
9 | extern crate clippy_lints;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: candidates:
          crate `clippy_lints`: /home/matthias/rust-clippy/target/debug/deps/libclippy_lints-814f215f3addd0a4.rlib
error[E0514]: found crate `clippy_lints` compiled by an incompatible version of rustc
 --> $DIR/useless_attribute.rs:9:1
  |
9 | extern crate clippy_lints;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: please recompile that crate using this compiler (rustc 1.26.0-nightly (ae544ee1c 2018-03-29))
  = note: the following crate versions were found:
          crate `clippy_lints` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libclippy_lints-6cd45c03a2306664.rlib
error: aborting due to 2 previous errors
Some errors occurred: E0464, E0514.
For more information about an error, try `rustc --explain E0464`.
expected stderr:
error: useless lint attribute
 --> $DIR/useless_attribute.rs:5:1
  |
5 | #[allow(dead_code, unused_extern_crates)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: if you just forgot a `!`, use: `#![allow(dead_code, unused_extern_crates)]`
  |
  = note: `-D useless-attribute` implied by `-D warnings`
error: useless lint attribute
 --> $DIR/useless_attribute.rs:6:1
  |
6 | #[cfg_attr(feature = "cargo-clippy", allow(dead_code, unused_extern_crates))]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: if you just forgot a `!`, use: `#![cfg_attr(feature = "cargo-clippy", allow(dead_code, unused_extern_crates))`
error: aborting due to 2 previous errors
diff of stderr:
-error: useless lint attribute
- --> $DIR/useless_attribute.rs:5:1
+error[E0464]: multiple matching crates for `clippy_lints`
+ --> $DIR/useless_attribute.rs:9:1
   |
-5 | #[allow(dead_code, unused_extern_crates)]
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: if you just forgot a `!`, use: `#![allow(dead_code, unused_extern_crates)]`
+9 | extern crate clippy_lints;
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
-  = note: `-D useless-attribute` implied by `-D warnings`
+  = note: candidates:
+          crate `clippy_lints`: /home/matthias/rust-clippy/target/debug/deps/libclippy_lints-814f215f3addd0a4.rlib
-error: useless lint attribute
- --> $DIR/useless_attribute.rs:6:1
+error[E0514]: found crate `clippy_lints` compiled by an incompatible version of rustc
+ --> $DIR/useless_attribute.rs:9:1
   |
-6 | #[cfg_attr(feature = "cargo-clippy", allow(dead_code, unused_extern_crates))]
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: if you just forgot a `!`, use: `#![cfg_attr(feature = "cargo-clippy", allow(dead_code, unused_extern_crates))`
+9 | extern crate clippy_lints;
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+  = help: please recompile that crate using this compiler (rustc 1.26.0-nightly (ae544ee1c 2018-03-29))
+  = note: the following crate versions were found:
+          crate `clippy_lints` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libclippy_lints-6cd45c03a2306664.rlib
 error: aborting due to 2 previous errors
+Some errors occurred: E0464, E0514.
+For more information about an error, try `rustc --explain E0464`.
The actual stderr differed from the expected stderr.
Actual stderr saved to /home/matthias/rust-clippy/target/debug/test_build_base/useless_attribute.stderr
To update references, run this command from build directory:
tests/ui/update-references.sh '/home/matthias/rust-clippy/target/debug/test_build_base' 'useless_attribute.rs'
error: 1 errors occurred comparing output.
status: exit code: 101
command: "target/debug/clippy-driver" "tests/ui/useless_attribute.rs" "-L" "/home/matthias/rust-clippy/target/debug/test_build_base" "--target=x86_64-unknown-linux-gnu" "-C" "prefer-dynamic" "-o" "/home/matthias/rust-clippy/target/debug/test_build_base/useless_attribute.stage-id" "-L" "target/debug" "-L" "target/debug/deps" "-Dwarnings" "-L" "/home/matthias/rust-clippy/target/debug/test_build_base/useless_attribute.stage-id.aux" "-A" "unused"
stdout:
------------------------------------------
------------------------------------------
stderr:
------------------------------------------
error[E0464]: multiple matching crates for `clippy_lints`
 --> tests/ui/useless_attribute.rs:9:1
  |
9 | extern crate clippy_lints;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: candidates:
          crate `clippy_lints`: /home/matthias/rust-clippy/target/debug/deps/libclippy_lints-814f215f3addd0a4.rlib
error[E0514]: found crate `clippy_lints` compiled by an incompatible version of rustc
 --> tests/ui/useless_attribute.rs:9:1
  |
9 | extern crate clippy_lints;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: please recompile that crate using this compiler (rustc 1.26.0-nightly (ae544ee1c 2018-03-29))
  = note: the following crate versions were found:
          crate `clippy_lints` compiled by rustc 1.26.0-nightly (188e693b3 2018-03-26): /home/matthias/rust-clippy/target/debug/deps/libclippy_lints-6cd45c03a2306664.rlib
error: aborting due to 2 previous errors
Some errors occurred: E0464, E0514.
For more information about an error, try `rustc --explain E0464`.
------------------------------------------
thread '[ui] ui/useless_attribute.rs' panicked at 'explicit panic', /home/matthias/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/compiletest_rs-0.3.9/src/runtest.rs:2539:9
failures:
    [ui] ui/regex.rs
    [ui] ui/serde.rs
    [ui] ui/useless_attribute.rs
test result: FAILED. 179 passed; 3 failed; 1 ignored; 0 measured; 0 filtered out
test compile_test ... FAILED
failures:
---- compile_test stdout ----
    thread 'compile_test' panicked at 'Some tests failed', /home/matthias/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/compiletest_rs-0.3.9/src/lib.rs:89:22
failures:
    compile_test
test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out

[oli-obk]

you probably need to cargo clean, because compiletest-rs doesn't know about the current build hash. At least that fixes it for me usually

[matthiaskrgr]

Ah, that worked. Thanks a lot!

[matthiaskrgr]

Hmm no, I still get failures. Something is weird.

[matthiaskrgr]

Hmm it seems something breaks when calling "cargo test" multiple times?

cargo clean
git clean -dffx #nuke everything
cargo build
cargo test # ok
cargo test # failed

[ghost]

I have to cargo clean after every test now as well.

[flip1995]

My workaround here is to just delete the files causing this error:

rm target/debug/deps/{libserde,libregex,libclippy_lints}*

With cargo clean the compilation after every test takes so long.

[oli-obk]

I'm guessing it's the dogfood test, which seems to be using the wrong rustc. In the above example, the crates seem to have been built with 188e693b3 2018-03-26, but the current rustc is ae544ee1c 2018-03-29

[oli-obk]

Jup, it's the dogfood test. You can disable it for now by renaming/removing it locally.

I'm juggling a few rustc PRs atm, so any help in fixing dogfood is appreciated.

[matthiaskrgr]

Seems to be fixed, closing.