Re-enable trivial bounds #51042

matthewjasper · 2018-05-24T20:48:14Z

Remove implementations from global bounds in winnowing when there is ambiguity.

This results in the reverse of #24066 happening sometimes. I'm not sure if anything can be done about that though.

rust-highfive · 2018-05-24T21:45:41Z

The job x86_64-gnu-llvm-3.9 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

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---
[00:51:29] failures:
[00:51:29] 
[00:51:29] ---- [ui] ui/feature-gate-trivial_bounds.rs stdout ----
[00:51:29] 
[00:51:29] error: /checkout/src/test/ui/feature-gate-trivial_bounds.rs:31: expected error not found: 
[00:51:29] 
[00:51:29] error: /checkout/src/test/ui/feature-gate-trivial_bounds.rs:62: expected error not found: 
[00:51:29] 
[00:51:29] error: 0 unexpected errors found, 2 expected errors not found
[00:51:29] status: exit code: 101
[00:51:29] command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/feature-gate-trivial_bounds.rs" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-C" "prefer-dynamic" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/feature-gate-trivial_bounds/a" "-Crpath" "-O" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/feature-gate-trivial_bounds/auxiliary" "-A" "unused"
[00:51:29] not found errors (from test file): [
[00:51:29]     Error {
[00:51:29]         line_num: 31,
[00:51:29]         kind: Some(
[00:51:29]         ),
[00:51:29]         ),
[00:51:29]         msg: ""
[00:51:29]     Error {
[00:51:29]         line_num: 62,
[00:51:29]         kind: Some(
[00:51:29]             Error
[00:51:29]             Error
[00:51:29]         ),
[00:51:29]         msg: ""
[00:51:29] ]
[00:51:29] 
[00:51:29] thread '[ui] ui/feature-gate-trivial_bounds.rs' panicked at 'explicit panic', tools/compiletest/src/runtest.rs:1283:13
[00:51:29] note: Run with `RUST_BACKTRACE=1` for a backtrace.
---
[00:51:29] 
[00:51:29] thread 'main' panicked at 'Some tests failed', tools/compiletest/src/main.rs:498:22
[00:51:29] 
[00:51:29] 
[00:51:29] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--src-base" "/checkout/src/test/ui" "--build-base" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--mode" "ui" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/usr/lib/llvm-3.9/bin/FileCheck" "--host-rustcflags" "-Crpath -O -Zunstable-options " "--target-rustcflags" "-Crpath -O -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--docck-python" "/usr/bin/python2.7" "--lldb-python" "/usr/bin/python2.7" "--gdb" "/usr/bin/gdb" "--quiet" "--llvm-version" "3.9.1\n" "--system-llvm" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--llvm-cxxflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"
[00:51:29] 
[00:51:29] 
[00:51:29] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[00:51:29] Build completed unsuccessfully in 0:02:48
[00:51:29] Build completed unsuccessfully in 0:02:48
[00:51:29] Makefile:58: recipe for target 'check' failed
[00:51:29] make: *** [check] Error 1

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:069e7e16
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

matthewjasper · 2018-05-24T21:56:14Z

Pushed a commit to fix #51044 as well

rust-highfive · 2018-05-24T22:58:25Z

The job x86_64-gnu-llvm-3.9 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

[00:58:54] ............................................i.......................................................
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[01:00:02] .....................................................................................i..............
[01:00:06] To only update this specific test, also pass `--test-args feature-gate-trivial_bounds.rs`
[01:00:06] error: 1 errors occurred comparing output.
[01:00:06] status: exit code: 101
[01:00:06] status: exit code: 101
[01:00:06] command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/feature-gate-trivial_bounds.rs" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-C" "prefer-dynamic" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/feature-gate-trivial_bounds/a" "-Crpath" "-O" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/feature-gate-trivial_bounds/auxiliary" "-A" "unused"
[01:00:06] ------------------------------------------
[01:00:06] 
[01:00:06] ------------------------------------------
[01:00:06] stderr:
[01:00:06] stderr:
[01:00:06] ------------------------------------------
[01:00:06] {"message":"the trait bound `i32: Foo` is not satisfied","code":{"code":"E0277","explanation":"\nYou tried to use a type which doesn't implement some trait in a place which\nexpected that trait. Erroneous code example:\n\n```compile_fail,E0277\n// here we declare the Foo trait with a bar method\ntrait Foo {\n    fn bar(&self);\n}\n\n// we now declare a function which takes an object implementing the Foo trait\nfn some_func<T: Foo>(foo: T) {\n    foo.bar();\n}\n\nfn main() {\n    // we now call the method with the i32 type, which doesn't implement\n    // the Foo trait\n    some_func(5i32); // error: the trait bound `i32 : Foo` is not satisfied\n}\n```\n\nIn order to fix this error, verify that the type you're using does implement\nthe trait. Example:\n\n```\ntrait Foo {\n    fn bar(&self);\n}\n\nfn some_func<T: Foo>(foo: T) {\n    foo.bar(); // we can now use this method since i32 implements the\n               // Foo trait\n}\n\n// we implement the trait on the i32 type\nimpl Foo for i32 {\n    fn bar(&self) {}\n}\n\nfn main() {\n    some_func(5i32); // ok!\n}\n```\n\nOr in a generic context, an erroneous code example would look like:\n\n```compile_fail,E0277\nfn some_func<T>(foo: T) {\n    println!(\"{:?}\", foo); // error: the trait `core::fmt::Debug` is not\n                           //        implemented for the type `T`\n}\n\nfn main() {\n    // We now call the method with the i32 type,\n    // which *does* implement the Debug trait.\n    some_func(5i32);\n}\n```\n\nNote that the error here is in the definition of the generic function: Although\nwe only call it with a parameter that does implement `Debug`, the compiler\nstill rejects the function: It must work with all possible input types. In\norder to make this example compile, we need to restrict the generic type we're\naccepting:\n\n```\nuse std::fmt;\n\n// Restrict the input type to types that implement Debug.\nfn some_func<T: fmt::Debug>(foo: T) {\n    println!(\"{:?}\", foo);\n}\n\nfn main() {\n    // Calling the method is still fine, as i32 implements Debug.\n    some_func(5i32);\n\n    // This would fail to compile now:\n    // struct WithoutDebug;\n    // some_func(WithoutDebug);\n}\n```\n\nRust only looks at the signature of the called function, as such it must\nalready specify all requirements that will be used for every type parameter.\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/feature-gate-trivial_bounds.rs","byte_start":592,"byte_end":619,"line_start":20,"line_end":20,"column_start":1,"column_end":28,"is_primary":true,"text":[{"text":"enum E where i32: Foo { V } //~ ERROR","highlight_start":1,"highlight_end":28}],"label":"the trait `Foo` is not implemented for `i32`","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"see issue #48214","code":null,"level":"help","spans":[],"children":[],"rendered":null},{"message":"add #![feature(trivial_bounds)] to the crate attributes to enable","code":null,"level":"help","spans":[],"children":[],"rendered":null}],"rendered":"error[E0277]: the trait bound `i32: Foo` is not satisfied\n  --> /checkout/src/test/ui/feature-gate-trivial_bounds.rs:20:1\n   |\nLL | enum E where i32: Foo { V } //~ ERROR\n   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `i32`\n   |\n   = help: see issue #48214\n   = help: add #![feature(trivial_bounds)] to the crate attributes to enable\n\n"}
[01:00:06] {"message":"the trait bound `i32: Foo` is not satisfied","code":{"code":"E0277","explanation":"\nYou tried to use a type which doesn't implement some trait in a place which\nexpected that trait. Erroneous code example:\n\n```compile_fail,E0277\n// here we declare the Foo trait with a bar method\ntrait Foo {\n    fn bar(&self);\n}\n\n// we now declare a function which takes an object implementing the Foo trait\nfn some_func<T: Foo>(foo: T) {\n    foo.bar();\n}\n\nfn main() {\n    // we now call the method with the i32 type, which doesn't implement\n    // the Foo trait\n    some_func(5i32); // error: the trait bound `i32 : Foo` is not satisfied\n}\n```\n\nIn order to fix this error, verify that the type you're using does implement\nthe trait. Example:\n\n```\ntrait Foo {\n    fn bar(&self);\n}\n\nfn some_func<T: Foo>(foo: T) {\n    foo.bar(); // we can now use this method since i32 implements the\n               // Foo trait\n}\n\n// we implement the trait on the i32 type\nimpl Foo for i32 {\n    fn bar(&self) {}\n}\n\nfn main() {\n    some_func(5i32); // ok!\n}\n```\n\nOr in a generic context, an erroneous code example would look like:\n\n```compile_fail,E0277\nfn some_func<T>(foo: T) {\n    println!(\"{:?}\", foo); // error: the trait `core::fmt::Debug` is not\n                           //        implemented for the type `T`\n}\n\nfn main() {\n    // We now call the method with the i32 type,\n    // which *does* implement the Debug trait.\n    some_func(5i32);\n}\n```\n\nNote that the error here is in the definition of the generic function: Although\nwe only call it with a parameter that does implement `Debug`, the compiler\nstill rejects the function: It must work with all possible input types. In\norder to make this example compile, we need to restrict the generic type we're\naccepting:\n\n```\nuse std::fmt;\n\n// Restrict the input type to types that implement Debug.\nfn some_func<T: fmt::Debug>(foo: T) {\n    println!(\"{:?}\", foo);\n}\n\nfn main() {\n    // Calling the method is still fine, as i32 implements Debug.\n    some_func(5i32);\n\n    // This would fail to compile now:\n    // struct WithoutDebug;\n    // some_func(Withouting the Foo trait\nfn some_func<T: Foo>(foo: T) {\n    foo.bar();\n}\n\nfn main() {\n    // we now call the method with the i32 type, which doesn't implement\n    // the Foo trait\n    some_func(5i32); // error: the trait bound `i32 : Foo` is not satisfied\n}\n```\n\nIn order to fix this error, verify that the type you're using does implement\nthe trait. Example:\n\n```\ntrait Foo {\n    fn bar(&self);\n}\n\nfn some_func<T: Foo>(foo: T) {\n    foo.bar(); // we can now use this method since i32 implements the\n               // Foo trait\n}\n\n// we implement the trait on the i32 type\nimpl Foo for i32 {\n    fn bar(&self) {}\n}\n\nfn main() {\n    some_func(5i32); // ok!\n}\n```\n\nOr in a generic context, an erroneous code example would look like:\n\n```compile_fail,E0277\nfn some_func<T>(foo: T) {\n    println!(\"{:?}\", foo); // error: the trait `core::fmt::Debug` is not\n                           //        implemented for the type `T`\n}\n\nfn main() {\n    // We now call the method with the i32 type,\n    // which *does* implement the Debug trait.\n    some_func(5i32);\n}\n```\n\nNote that the error here is in the definition of the generic function: Although\nwe only call it with a parameter that does implement `Debug`, the compiler\nstill rejects the function: It must work with all possible input types. In\norder to make this example compile, we need to restrict the generic type we're\naccepting:\n\n```\nuse std::fmt;\n\n// Restrict the input type to types that implement Debug.\nfn some_func<T: fmt::Debug>(foo: T) {\n    println!(\"{:?}\", foo);\n}\n\nfn main() {\n    // Calling the method is still fine, as i32 implements Debug.\n    some_func(5i32);\n\n    // This would fail to compile now:\n    // struct WithoutDebug;\n    // some_func(WithoutDebug);\n}\n```\n\nRust only looks at the signature of the called function, as such it must\nalready specify all requirements that will be used for every type parameter.\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/feature-gate-trivial_bounds.rs","byte_start":667,"byte_end":692,"line_start":24,"line_end":24,"column_start":1,"column_end":26,"is_primary":true,"text":[{"text":"trait T where i32: Foo {} //~ ERROR","highlight_start":1,"highlight_end":26}],"label":"the trait `Foo` is not implemented for `i32`","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"see issue #48214","code":null,"level":"help","spans":[],"children":[],"rendered":null},{"message":"add #![feature(trivial_bounds)] to the crate attributes to enable","code":null,"level":"help","spans":[],"children":[],"rendered":null}],"rendered":"error[E0277]: the trait bound `i32: Foo` is not satisfied\n  --> /checkout/src/test/ui/feature-gate-trivial_bounds.rs:24:1\n   |\nLL | trait T where i32: Foo {} //~ ERROR\n   | ^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `i32`\n   |\n   = help: see issue #48214\n   = help: add #![feature(trivial_bounds)] to the crate attributes to enable\n\n"}
[01:00:06] {"message":"the trait bound `i32: Foo` is not satisfied","code":{"code":"E0277","explanation":"\nYou tried to use a type which doesn't implement some trait in a place which\nexpected that trait. Erroneous code example:\n\n```compile_fail,E0277\n// here we declar:"the trait bound `i32: Foo` is not satisfied","code":{"code":"E0277","explanation":"\nYou tried to use a type which doesn't implement some trait in a place which\nexpected that trait. Erroneous code example:\n\n```compile_fail,E0277\n// here we declare the Foo trait with a bar method\ntrait Foo {\n    fn bar(&self);\n}\n\n// we now declare a function which takes an object implementing the Foo trait\nfn some_func<T: Foo>(foo: T) {\n    foo.bar();\n}\n\nfn main() {\n    // we now call the method with the i32 type, which doesn't implement\n    // the Foo trait\n    some_func(5i32); // error: the trait bound `i32 : Foo` is not satisfied\n}\n```\n\nIn order to fix this error, verify that the type you're using does implement\nthe trait. Example:\n\n```\ntrait Foo {\n    fn bar(&self);\n}\n\nfn some_func<T: Foo>(foo: T) {\n    foo.bar(); // we can now use this method since i32 implements the\n               // Foo trait\n}\n\n// we implement the trait on the i32 type\nimpl Foo for i32 {\n    fn bar(&self) {}\n}\n\nfn main() {\n    some_func(5i32); // ok!\n}\n```\n\nOr in a generic context, an erroneous code example would look like:\n\n```compile_fail,E0277\nfn some_func<T>(foo: T) {\n    println!(\"{:?}\", foo); // error: the trait `core::fmt::Debug` is not\n                           //        implemented for the type `T`\n}\n\nfn main() {\n    // We now call the method with the i32 type,\n    // which *does* implement the Debug trait.\n    some_func(5i32);\n}\n```\n\nNote that the error here is in the definition of the generic function: Although\nwe only call it with a parameter that does implement `Debug`, the compiler\nstill rejects the function: It must work with all possible input types. In\norder to make this example compile, we need to restrict the generic type we're\naccepting:\n\n```\nuse std::fmt;\n\n// Restrict the input type to types that implement Debug.\nfn some_func<T: fmt::Debug>(foo: T) {\n    println!(\"{:?}\", foo);\n}\n\nfn main() {\n    // Calling the method is still fine, as i32 implements Debug.\n    some_func(5i32);\n\n    // This would fail to compile now:\n    // struct WithoutDebug;\n    // some_func(WithoutDebug);\n}\n```\n\nRust only looks at the signature of the called function, as such it must\nalready specify all requirements that will be used for every type parameter.\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/feature-gate-trivial_bounds.rs","byte_start":803,"byte_end":953,"line_start":30,"line_end":36,"column_start":1,"column_end":2,"is_primary":true,"text":[{"text":"impl Foo for () where i32: Foo { //~ ERROR","highlight_start":1,"highlight_end":43},{"text":"    fn test(&self) {","highlight_start":1,"highlight_end":21},{"text":"        3i32.test();","highlight_start":1,"highlight_end":21},{"text":"        Foo::test(&4i32);","highlight_start":1,"highlight_end":26},{"text":"        generic_function(5i32);","highlight_start":1,"highlight_end":32},{"text":"    }","highlight_start":1,"highlight_end":6},{"text":"}","highlight_start":1,"highlight_end":2}],"label":"the trait `Foo` is not implemented for `i32`","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"see issue #48214","code":null,"level":"help","spans":[],"children":[],"rendered":null},{"message":"add #![feature(trivial_bounds)] to the crate attributes to enable","code":null,"level":"help","spans":[],"children":[],"rendered":null}],"rendered":"error[E0277]: the trait bound `i32: Foo` is not satisfied\n  --> /checkout/src/test/ui/feature-gate-trivial_bounds.rs:30:1\n   |\nLL | / impl Foo for () where i32: Foo { //~ ERROR\nLL | |     fn test(&self) {\nLL | |         3i32.test();\nLL | |         Foo::test(&4i32);\nLL | |         generic_function(5i32);\nLL | |     }\nLL | | }\n   | |_^ the trait `Foo` is not implemented for `i32`\n   |\n   = help: see issue #48214\n   = help: add #![feature(trivial_bounds)] to the crate attributes to enable\n\n"}
[01:00:06] {"message":"the trait bound `i32: Foo` is not satisfied","code":{"code":"E0277","explanation":"\nYou tried to use a type which doesn't implement some trait in a place which\nexpected that trait. Erroneous code example:\n\n```compile_fail,E0277\n// here we declare the Foo trait with a bar method\ntrait Foo {\n    fn bar(&self);\n}\n\n// we now declare a function which takes an object implementing the Foo trait\nfn some_func<T: Foo>(foo: T) {\n    foo.bar();\n}\n\nfn main() {\n    // we now call the method with the i32 type, which doesn't implement\n    // the Foo trait\n    some_func(5i32); // error: the trait bound `i32 : Foo` is not satisfied\n}\n```\n\nIn order to fix this error, verify that the type you're using does implement\nthe trait. Example:\n\n```\ntrait Foo {\n    fn bar(&self);\n}\n\nfn some_func<T: Foo>(foo: T) {\n    foo.bar(); // we can now use this method since i32 implements the\n               // Foo trait\n}\n\n// we implement the trait on the\n}\n\n// we now declare a function which takes an object implementing the Foo trait\nfn some_func<T: Foo>(foo: T) {\n    foo.bar();\n}\n\nfn main() {\n    // we now call the method with the i32 type, which doesn't implement\n    // the Foo trait\n    some_func(5i32); // error: the trait bound `i32 : Foo` is not satisfied\n}\n```\n\nIn order to fix this error, verify that the type you're using does implement\nthe trait. Example:\n\n```\ntrait Foo {\n    fn bar(&self);\n}\n\nfn some_func<T: Foo>(foo: T) {\n    foo.bar(); // we can now use this method since i32 implements the\n               // Foo trait\n}\n\n// we implement the trait on the i32 type\nimpl Foo for i32 {\n    fn bar(&self) {}\n}\n\nfn main() {\n    some_func(5i32); // ok!\n}\n```\n\nOr in a generic context, an erroneous code example would look like:\n\n```compile_fail,E0277\nfn some_func<T>(foo: T) {\n    println!(\"{:?}\", foo); // error: the trait `core::fmt::Debug` is not\n                           //        implemented for the type `T`\n}\n\nfn main() {\n    // We now call the method with the i32 type,\n    // which *does* implement the Debug trait.\n    some_func(5i32);\n}\n```\n\nNote that the error here is in the definition of the generic function: Although\nwe only call it with a parameter that does implement `Debug`, the compiler\nstill rejects the function: It must work with all possible input types. In\norder to make this example compile, we need to restrict the generic type we're\naccepting:\n\n```\nuse std::fmt;\n\n// Restrict the input type to types that implement Debug.\nfn some_func<T: fmt::Debug>(foo: T) {\n    println!(\"{:?}\", foo);\n}\n\nfn main() {\n    // Calling the method is still fine, as i32 implements Debug.\n    some_func(5i32);\n\n    // This would fail to compile now:\n    // struct WithoutDebug;\n    // some_func(WithoutDebug);\n}\n```\n\nRust only looks at the signature of the called function, as such it must\nalready specify all requirements that will be used for every type parameter.\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/feature-gate-trivial_bounds.rs","byte_start":1074,"byte_end":1170,"line_start":46,"line_end":48,"column_start":1,"column_end":2,"is_primary":true,"text":[{"text":"fn use_op(s: String) -> String where String: ::std::ops::Neg<Output=String> { //~ ERROR","highlight_start":1,"highlight_end":88},{"text":"    -s","highlight_start":1,"highlight_end":7},{"text":"}","highlight_start":1,"highlight_end":2}],"label":"the trait `std::ops::Neg` is not implemented for `std::string::String`","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"see issue #48214","code":null,"level":"help","spans":[],"children":[],"rendered":null},{"message":"add #![feature(trivial_bounds)] to the crate attributes to enable","code":null,"level":"help","spans":[],"children":[],"rendered":null}],"rendered":"error[E0277]: the trait bound `std::string::String: std::ops::Neg` is not satisfied\n  --> /checkout/src/test/ui/feature-gate-trivial_bounds.rs:46:1\n   |\nLL | / fn use_op(s: String) -> String where String: ::std::ops::Neg<Output=String> { //~ ERROR\nLL | |     -s\nLL | | }\n   | |_^ the trait `std::ops::Neg` is not implemented for `std::string::String`\n   |\n   = help: see issue #482ition of the generic function: Although\nwe only call it with a parameter that does implement `Debug`, the compiler\nstill rejects the function: It must work with all possible input types. In\norder to make this example compile, we need to restrict the generic type we're\naccepting:\n\n```\nuse std::fmt;\n\n// Restrict the input type to types that implement Debug.\nfn some_func<T: fmt::Debug>(foo: T) {\n    println!(\"{:?}\", foo);\n}\n\nfn main() {\n    // Calling the method is still fine, as i32 implements Debug.\n    some_func(5i32);\n\n    // This would fail to compile now:\n    // struct WithoutDebug;\n    // some_func(WithoutDebug);\n}\n```\n\nRust only looks at the signature of the called function, as such it must\nalready specify all requirements that will be used for every type parameter.\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/feature-gate-trivial_bounds.rs","byte_start":1172,"byte_end":1239,"line_start":50,"line_end":52,"column_start":1,"column_end":2,"is_primary":true,"text":[{"text":"fn use_for() where i32: Iterator { //~ ERROR","highlight_start":1,"highlight_end":45},{"text":"    for _ in 2i32 {}","highlight_start":1,"highlight_end":21},{"text":"}","highlight_start":1,"highlight_end":2}],"label":"`i32` is not an iterator; maybe try calling `.iter()` or a similar method","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"the trait `std::iter::Iterator` is not implemented for `i32`","code":null,"level":"help","spans":[],"children":[],"rendered":null},{"message":"see issue #48214","code":null,"level":"help","spans":[],"children":[],"renden\n// we implement the trait on the i32 type\nimpl Foo for i32 {\n    fn bar(&self) {}\n}\n\nfn main() {\n    some_func(5i32); // ok!\n}\n```\n\nOr in a generic context, an erroneous code example would look like:\n\n```compile_fail,E0277\nfn some_func<T>(foo: T) {\n    println!(\"{:?}\", foo); // error: the trait `core::fmt::Debug` is not\n                           //        implemented for the type `T`\n}\n\nfn main() {\n    // We now call the method with the i32 type,\n    // which *does* implement the Debug trait.\n    some_func(5i32);\n}\n```\n\nNote that the error here is in the definition of the generic function: Although\nwe only call it with a parameter that does implement `Debug`, the compiler\nstill rejects the function: It must work with all possible input types. In\norder to make this example compile, we need to restrict the generic type we're\naccepting:\n\n```\nuse std::fmt;\n\n// Restrict the input type to types that implement Debug.\nfn some_func<T: fmt::Debug>(foo: T) {\n    println!(\"{:?}\", foo);\n}\n\nfn main() {\n    // Calling the method is still fine, as i32 implements Debug.\n    some_func(5i32);\n\n    // This would fail to compile now:\n    // struct WithoutDebug;\n    // some_func(WithoutDebug);\n}\n```\n\nRust only looks at the signature of the called function, as such it must\nalready specify all requirements that will be used for every type parameter.\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/feature-gate-trivial_bounds.rs","byte_start":1309,"byte_end":1351,"line_start":62,"line_end":62,"column_start":1,"column_end":43,"is_primary":true,"text":[{"text":"struct TwoStrs(str, str) where str: Sized; //~ ERROR","highlight_start":1,"highlight_end":43}],"label":"`str` does not have a constant size known at compile-time","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"the trait `std::marker::Sized` is not implemented for `str`","code":null,"level":"help","spans":[],"children":[],"rendered":null},{"message":"see issue #48214","code":null,"level":"help","spans":[],"children":[],"rendered":null},{"message":"add #![feature(trivial_bounds)] to the crate attributes to enable","code":null,"level":"help","spans":[],"children":[],"rendered":null}],"rendered":"error[E0277]: the trait bound `str: std::marker::Sized` is not satisfied\n  --> /checkout/src/test/ui/feature-gate-trivial_bounds.rs:62:1\n   |\nLL | struct TwoStrs(str, str) where str: Sized; //~ ERROR\n   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `str` does not have a constant size known at compile-time\n   |\n   = help: the trait `std::marker::Sized` is not implemented for `str`\n   = help: see issue #48214\n   = help: add #![feature(trivial_bounds)] to the crate attributes to enable\n\n"}
[01:00:06] {"message":"the trait bound `A + 'static: std::marker::Sized` is not satisfied in `Dst<A + 'static>`","code":{"code":"E0277","explanation":"\nYou tried to use a type which doesn't implement some trait in a place which\nexpected that trait. Erroneous code example:\n\n```compile_fail,E0277\n// here we declare the Foo trait with a bar method\ntrait Foo {\n    fn bar(&self);\n}\n\n// we now declare a function which takes an object implementing the Foo trait\nfn some_func<T: Foo>(foo: T) {\n    foo.bar();\n}\n\nfn main() {\n    // we now call the method with the i32 type, which doesn't implement\n    // the Foo trait\n    some_func(5i32); // error: the trait bound `i32 : Foo` is not satisfied\n}\n```\n\nIn order to fix this error, verify that the type you're using does implement\nthe trait. Example:\n\n```\ntrait Foo {\n    fn bar(&self);\n}\n\nfn some_func<T: Foo>(foo: T) {\n    foo.bar(); // we can now use this method since i32 implements the\n               // Foo trait\n}\n\n// we implement the trait on the i32 type\nimpl Foo for i32 {\n    fn bar(&self) {}\n}\n\nfn main() {\n    some_func(5i32); // ok!\n}\n```\n\nOr in a generic context, an erroneous code example would look like:\n\n```compile_fail,E0277\nfn some_func<T>(foo: T) {\n    println!(\"{:?}\", foo); // error: the trait `core::fmt::Debug` is not\n                           //        implemented for the type `T`\n}\n\nfn main() {\n    // We now call the method with the i32 type,\n    // which *does* implement the Debug trait.\n    some_func(5i32);\n}\n```\n\nNote that the error here is in the definition of the generic function: Although\nwe only call it with a parameter that does implement `Debug`, the compiler\nstill rejects the function: It must work with all possible input types. In\norder to make this example compile, we need to restrict the generic type we're\naccepting:\n\n```\nuse std::fmt;\n\n// Restrict the input type to types that implement Debug.\nfn some_func<T: fmt::Debug>(foo: T) {\n    println!(\"{:?}\", foo);\n}\n\nfn main() {\n    // Calling the method is still fine, as i32 implements Debug.\n    some_func(5i32);\n\n    // This would fail to fn unsized_local() where Dst<A>: Sized { //~ ERROR\nLL | |     let x: Dst<A> = *(Box::new(Dst { x: 1 }) as Box<Dst<A>>);\nLL | | }\n   | |_^ `A + 'static` does not have a constant size known at compile-time\n   |\n   = help: within `Dst<A + 'static>`, the trait `std::marker::Sized` is not implemented for `A + 'static`\n   = note: required because it appears within the type `Dst<A + 'static>`\n   = help: see issue #48214\n   = help: add #![feature(trivial_bounds)] to the crate attributes to enable\n\n"}
[01:00:06] {"message":"the trait bound `str: std::marker::Sized` is not satisfied","code":{"code":"E0277","explanation":"\nYou tried to use a type which doesn't implement some trait in a place which\nexpected that trait. Erroneous code example:\n\n```compile_fail,E0277\n// here we declare the Foo trait with a bar method\ntrait Foo {\n    fn bar(&self);\n}\n\n// we now declare a function which takes an object implementing the Foo trait\nfn some_func<T: Foo>(foo: T) {\n    foo.bar();\n}\n\nfn main() {\n    // we now call the method with the i32 type, which doesn't implement\n    // the Foo trait\n    some_func(5i32); // error: the trait bound `i32 : Foo` is not satisfied\n}\n```\n\nIn order to fix this error, verify that the type you're using does implement\nthe trait. Example:\n\n```\ntrait Foo {\n    fn bar(&self);\n}\n\nfn some_func<T: Foo>(foo: T) {\n    foo.bar(); // we can now use this method since i32 implements the\n               // Foo trait\n}\n\n// we implement the trait on the i32 type\nimpl Foo for i32 {\n    fn bar(&self) {}\n}\n\nfn main() {\n    some_func(5i32); // ok!\n}\n```\n\nOr in a generic context, an erroneous code example would look like:\n\n```compile_fail,E0277\nfn some_func<T>(foo: T) {\n    println!(\"{:?}\", foo); // error: the trait `core::fmt::Debug` is not\n                           //        implemented for the type `T`\n}\n\nfn main() {\n    // We now call the method with the i32 type,\n    // which *does* implement the Debug trait.\n    some_func(5i32);\n}\n```\n\nNote that the error here is in the definition of the generic function: Although\nwe only call it with a parameter that does implement `Debug`, the compiler\nstill rejects the function: It must work with all possible input types. In\norder to make this example compile, we need to restrict the generic type we're\naccepting:\n\n```\nuse std::fmt;\n\n// Restrict the input type to types that implement Debug.\nfn some_func<T: fmt::Debug>(foo: T) {\n    println!(\"{:?}\", foo);\n}\n\nfn main() {\n    // Calling the method is still fine, as i32 implements Debug.\n    some_func(5i32);\n\n    // This would fail to compile now:\n    // struct WithoutDebug;\n    // some_func(WithoutDebug);\n}\n```\n\nRust only looks at the signature of the called function, as such it must\nalready specify all requirements that will be used for every type parameter.\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/feature-gate-trivial_bounds.rs","byte_start":1480,"byte_end":1575,"line_start":69,"line_end":71,"column_start":1,"column_end":2,"is_primary":true,"text":[{"text":"fn return_str() -> str where str: Sized { //~ ERROR","highlight_start":1,"highlight_end":52},{"text":"    *\"Sized\".to_string().into_boxed_str()","highlight_start":1,"highlight_end":42},{"text":it code: 101
[01:00:06] 
[01:00:06] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[01:00:06] Build completed unsuccessfully in 0:03:20
[01:00:06] Build completed unsuccessfully in 0:03:20
[01:00:06] Makefile:58: recipe for target 'check' failed
[01:00:06] make: *** [check] Error 1

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:0d8d3720
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

rust-highfive · 2018-05-25T19:37:33Z

The job x86_64-gnu-llvm-3.9 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

[01:17:28] ..............................................................................................i.....
[01:17:32] ....................................................................................................
[01:17:39] ....................................................................................................
[01:17:45] ....................................................................................................
[01:17:52] ................F...................................................................................
[01:18:08] ....................................................................................................
[01:18:14] ...i................................................................................................
[01:18:21] ..i..ii.............................................................................................
[01:18:30] ....................................................................................................
---
[01:19:10] failures:
[01:19:10] 
[01:19:10] ---- [compile-fail] compile-fail/issue-36839.rs stdout ----
[01:19:10] 
[01:19:10] error: /checkout/src/test/compile-fail/issue-36839.rs:24: unexpected error: '24:5: 26:6: the trait bound `(): Foo` is not satisfied [E0277]'
[01:19:10] 
[01:19:10] error: /checkout/src/test/compile-fail/issue-36839.rs:30: expected error not found: compilation successful
[01:19:10] 
[01:19:10] error: 1 unexpected errors found, 1 expected errors not found
[01:19:10] status: exit code: 101
[01:19:10] command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/compile-fail/issue-36839.rs" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-C" "prefer-dynamic" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail/issue-36839/a" "-Crpath" "-O" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail/issue-36839/auxiliary" "-A" "unused"
[01:19:10] unexpected errors (from JSON output): [
[01:19:10]     Error {
[01:19:10]         line_num: 24,
[01:19:10]         kind: Some(
[01:19:10]         ),
[01:19:10]         ),
[01:19:10]         msg: "24:5: 26:6: the trait bound `(): Foo` is not satisfied [E0277]"
[01:19:10] ]
[01:19:10] 
[01:19:10] not found errors (from test file): [
[01:19:10]     Error {
[01:19:10]     Error {
[01:19:10]         line_num: 30,
[01:19:10]         kind: Some(
[01:19:10]             Error
[01:19:10]         ),
[01:19:10]         msg: "compilation successful"
[01:19:10] ]
[01:19:10] 
[01:19:10] thread '[compile-fail] compile-fail/issue-36839.rs' panicked at 'explicit panic', tools/compiletest/src/runtest.rs:1283:13
[01:19:10] note: Run with `RUST_BACKTRACE=1` for a backtrace.
---
[01:19:10] 
[01:19:10] thread 'main' panicked at 'Some tests failed', tools/compiletest/src/main.rs:498:22
[01:19:10] 
[01:19:10] 
[01:19:10] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--src-base" "/checkout/src/test/compile-fail" "--build-base" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--mode" "compile-fail" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/usr/lib/llvm-3.9/bin/FileCheck" "--host-rustcflags" "-Crpath -O -Zunstable-options " "--target-rustcflags" "-Crpath -O -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--docck-python" "/usr/bin/python2.7" "--lldb-python" "/usr/bin/python2.7" "--gdb" "/usr/bin/gdb" "--quiet" "--llvm-version" "3.9.1\n" "--system-llvm" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--llvm-cxxflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"
[01:19:10] 
[01:19:10] 
[01:19:10] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[01:19:10] Build completed unsuccessfully in 0:20:03
[01:19:10] Build completed unsuccessfully in 0:20:03
[01:19:10] Makefile:58: recipe for target 'check' failed
[01:19:10] make: *** [check] Error 1

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:0f7d4b79
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

TimNN · 2018-05-29T19:19:29Z

Triage ping, @nikomatsakis, this PR is waiting for your review.

pietroalbini · 2018-06-04T10:47:07Z

Ping from triage! This PR needs a review, can @nikomatsakis or someone else from @rust-lang/compiler review this?

nikomatsakis · 2018-06-05T17:21:46Z

I will review this one, but I haven't gotten to it yet.

nikomatsakis · 2018-06-08T15:18:11Z

src/librustc/traits/select.rs

@@ -2025,13 +2022,46 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
        other: &EvaluatedCandidate<'tcx>)
        -> bool
    {
+        // Check if a bound would previously have been removed when normalizing
+        // the param_env so that it can be given the lowest priority. See
+        // #50825 for the motivation for this.


Ugh. But makes sense. Chalk can't come soon enough!

nikomatsakis · 2018-06-08T15:19:58Z

src/librustc/traits/select.rs

-                        let tcx = self.tcx().global_tcx();
-                        return tcx.specializes((other_def, victim_def)) ||
-                            tcx.impls_are_allowed_to_overlap(other_def, victim_def);
+                    // FIXME also have an is_global here?


Not sure what this FIXME is suggesting -- you did add one in ParamCandidate case, which seems like the case where it would be relevant..?

I just forgot to remove the comment

Eijebong · 2018-06-08T15:49:16Z

I confirm that this makes diesel master compile again 🎉

Removes extra global bounds at the winnowing stage rather than when normalizing the param_env. This avoids breaking inference when there is a global bound.

nikomatsakis · 2018-06-08T20:08:50Z

@bors r+

bors · 2018-06-08T20:08:51Z

📌 Commit a1bddcf has been approved by nikomatsakis

bors · 2018-06-08T20:08:52Z

🌲 The tree is currently closed for pull requests below priority 1, this pull request will be tested once the tree is reopened

nikomatsakis · 2018-06-08T20:09:03Z

@bors r- -- oops, had a few questions

nikomatsakis · 2018-06-08T20:09:38Z

In particular, I wanted to know what was up with that FIXME -- maybe we should just remove it? I suspect it is outdated.

lnicola · 2018-06-08T20:13:13Z

@nikomatsakis #51042 (comment)

nikomatsakis · 2018-06-09T00:50:13Z

Oh, I missed that =)

@bors r+ p=1 -- fixes regressions

bors · 2018-06-09T00:50:14Z

📌 Commit a1bddcf has been approved by nikomatsakis

bors · 2018-06-09T01:32:55Z

⌛ Testing commit a1bddcf with merge 1c5626f...

@nikomatsakis

…atsakis Re-enable trivial bounds cc #50825 Remove implementations from global bounds in winnowing when there is ambiguity. This results in the reverse of #24066 happening sometimes. I'm not sure if anything can be done about that though. cc #48214 r? @nikomatsakis

bors · 2018-06-09T03:41:26Z

☀️ Test successful - status-appveyor, status-travis
Approved by: nikomatsakis
Pushing 1c5626f to master...

rust-highfive assigned nikomatsakis May 24, 2018

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label May 24, 2018

matthewjasper force-pushed the reenable-trivial-bounds branch from b66c17e to 3339eea Compare May 24, 2018 21:55

Eijebong mentioned this pull request May 24, 2018

Compile fails on latest nightly rust 1.28.0 diesel-rs/diesel#1730

Closed

2 tasks

matthewjasper force-pushed the reenable-trivial-bounds branch from 3339eea to b384d6e Compare May 25, 2018 18:15

weiznich mentioned this pull request May 25, 2018

the trait bound <expression::count::CountStar as expression::Expression>::SqlType: sql_types::ops::Add is not satisfied diesel-rs/diesel#1731

Closed

matthewjasper force-pushed the reenable-trivial-bounds branch from b384d6e to ffb93bf Compare May 25, 2018 21:37

Eijebong mentioned this pull request May 28, 2018

Diesel v1.3.1 compilation failed diesel-rs/diesel#1737

Closed

2 tasks

rizakrko mentioned this pull request May 31, 2018

update deps diesel-rs/diesel#1742

Closed

matthewjasper mentioned this pull request May 31, 2018

Can't compile brotli with rustc 1.27.0-nightly (2f2a11dfc 2018-05-16) #50825

Closed

mbilker mentioned this pull request Jun 1, 2018

maud_macros does not work under older Rust nightly versions lambda-fairy/maud#132

Closed

weiznich mentioned this pull request Jun 6, 2018

Unable to build with latest nightly version. diesel-rs/diesel#1754

Closed

nikomatsakis approved these changes Jun 8, 2018

View reviewed changes

matthewjasper force-pushed the reenable-trivial-bounds branch from d748578 to c8f4ef1 Compare June 8, 2018 15:58

matthewjasper added 5 commits June 8, 2018 17:00

Reenable trivial bounds

ba35e80

Removes extra global bounds at the winnowing stage rather than when normalizing the param_env. This avoids breaking inference when there is a global bound.

Add tests for associated types and inconsistent bounds

87f63ca

Test that object bounds are preferred over global where clause bounds

0476a87

Fix a typo

9d7613a

Normalize associated types when checking global bounds

a1bddcf

matthewjasper force-pushed the reenable-trivial-bounds branch from c8f4ef1 to a1bddcf Compare June 8, 2018 16:01

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 8, 2018

bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Jun 8, 2018

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jun 9, 2018

bors merged commit a1bddcf into rust-lang:master Jun 9, 2018

bors mentioned this pull request Jun 9, 2018

add dyn to display of dynamic (trait) types #51104

Merged

This was referenced Jun 10, 2018

trivial_bounds doesn't see associated type as implementing a trait #51044

Closed

Tracking issue for RFC #2056: Allow trivial constraints to appear in where clauses #48214

Open

matthewjasper deleted the reenable-trivial-bounds branch September 3, 2018 21:32

aliemjay mentioned this pull request Dec 15, 2023

special-casing 'static when winnowing trivial candidates #118965

Open

Re-enable trivial bounds #51042

Re-enable trivial bounds #51042

Uh oh!

Conversation

matthewjasper commented May 24, 2018

Uh oh!

rust-highfive commented May 24, 2018

Uh oh!

matthewjasper commented May 24, 2018

Uh oh!

rust-highfive commented May 24, 2018

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rust-highfive commented May 25, 2018

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TimNN commented May 29, 2018

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pietroalbini commented Jun 4, 2018

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Eijebong commented Jun 8, 2018

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bors commented Jun 8, 2018

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bors commented Jun 9, 2018

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bors commented Jun 9, 2018

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bors commented Jun 9, 2018

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