Clarified E0015 message.

[krk]

Closes #46336

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @michaelwoerister (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see the contribution instructions for more information.

[michaelwoerister]

r? @estebank

[rust-highfive]

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.

[00:00:47] configure: rust.quiet-tests     := True
---
[00:42:45] .................................................................................i..................
[00:42:51] ..................F.....i...........................................................................
---
[00:43:32] .....................i...........................................................................i..
[00:43:38] ....................................................................................................
[00:43:44] ...........ii.......................................................................................
[00:43:53] ............................................................................................i.......
---
[00:43:56] 4 LL |     let mut sum = 0;
[00:43:56] 5    |                   ^
[00:43:56] 6
[00:43:56] - error[E0015]: calls in constant functions are limited to constant functions, struct and enum constructors
[00:43:56] + error[E0015]: calls in constant functions are limited to constant functions, tuple structs and tuple variants
[00:43:56] 8   --> $DIR/const-fn-error.rs:18:14
[00:43:56] 9    |
[00:43:56] 10 LL |     for i in 0..x {
[00:43:56]
[00:43:56]
[00:43:56] The actual stderr differed from the expected stderr.
[00:43:56] Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/const-fn-error.stderr
[00:43:56] To update references, run this command from build directory:
[00:43:56] /checkout/src/test/ui/update-references.sh '/umn_start":19,"column_end":20,"is_primary":true,"text":[{"text":"    let mut sum = 0;","highlight_start":19,"highlight_end":20}],"label":null,"suggested_replacement":null,"expansion":null}],"children":[],"rendered":"error[E0016]: blocks in constant functions are limited to items and tail expressions\n  --> /checkout/src/test/ui/const-fn-error.rs:16:19\n   |\nLL |     let mut sum = 0;\n   |                   ^\n\n"}
[00:43:56] {"message":"calls in constant functions are limited to constant functions, tuple structs and tuple variants","code":{"code":"E0015","explanation":"\nThe only functions that can be called in static or constant expressions are\n`const` functions, and struct/enum constructors. `const` functions are only\navailable on a nightly compiler. Rust currently does not support more general\ncompile-time function execution.\n\n```\nconst FOO: Option<u8> = Some(1); // enum constructor\nstruct Bar {x: u8}\nconst BAR: Bar = Bar {x: 1}; // struct constructor\n```\n\nSee [RFC 911] for more details on the design of `const fn`s.\n\n[RFC 911]: https://github.com/rust-lang/rfcs/blob/master/text/0911-const-fn.md\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/const-fn-error.rs","byte_start":599,"byte_end":603,"line_start":18,"line_end":18,"column_start":14,"column_end":18,"is_primary":true,"text":[{"text":"    for i in 0..x {","highlight_start":14,"highlight_end":18}],"label":null,"suggested_replacement":null,"expansion":{"span":{"file_name":"/checkout/src/test/ui/const-fn-error.rs","byte_start":599,"byte_end":603,"line_start":18,"line_end":18,"column_start":14,"column_end":18,"is_primary":false,"text":[{"text":"    for i in 0..x {","highlight_start":14,"highlight_end":18}],"label":null,"suggested_replacement":null,"expansion":null},"macro_decl_name":"desugaring of `...`","def_site_span":{"file_name":"/checkout/src/test/ui/const-fn-error.rs","byte_start":599,"byte_end":603,"line_start":18,"line_end":18,"column_start":14,"column_end":18,"is_primary":false,"text":[{"text":"    for i in 0..x {","highlight_start":14,"highlight_end":18}],"label":null,"suggested_replacement":null,"expansion":null}}}],"children":[],"rendered":"error[E0015]: calls in constant functions are limited to constant functions, tuple structs and tuple variants\n  --> /checkout/src/test/ui/const-fn-error.rs:18:14\n   |\nLL |     for i in 0..x {\n   |              ^^^^\n\n"}
[00:43:56] {"message":"constant function contains unimplemented expression type","code":{"code":"E0019","explanation":"\nA function call isn't allowed in the const's initialization expression\nbecause the expression's value must be known at compile-time. Erroneous code\nexample:\n\n```compile_fail\nenum Test {\n    V1\n}\n\nimpl Test {\n    fn test(&self) -> i32 {\n        12\n    }\n}\n\nfn main() {\n    const FOO: Test = Test::V1;\n\n    const A: i32 = FOO.test(); // You can't call Test::func() here!\n}\n```\n\nRemember: you can't use a function call inside a const's initialization\nexpression! However, you can totally use it anywhere else:\n\n```\nenum Test {\n    V1\n}\n\nimpl Test {\n    fn func(&self) -> i32 {\n        12\n    }\n}\n\nfn main() {\n    const FOO: Test = Test::V1;\n\n    FOO.func(); // here is good\n    let x = FOO.func(); // or even here!\n}\n```\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/const-fn-error.rs","byte_start":599,"byte_end":603,"line_start":18,"line_end":18,"column_start":14,"column_end":18,"is_primary":true,"text":[{"text":"    for i in 0..x {","highlight_start":14,"highlight_end":18}],"label":null,"suggested_replacement":null,"expansion":{"span":{"file_name":"/checkout/src/test/ui/const-fn-error.rs","byte_start":599,"byte_end":603,"line_start":18,"line_end":18,"column_start":14,"column_end":18,"is_primary":false,"text":[{"text":"    for i in 0..x {","highlight_start":14,"highlight_end":18}],"label":null,"suggested_replacement":null,"expansion":null},"macro_decl_name":"desugaring of `...`","def_site_span":{"file_name":"/checkout/src/test/ui/const-fn-error.rs","byte_start":599,"byte_end":603,"line_start":18,"line_end":18,"column_start":14,"column_end":18,"is_primary":false,"text":[{"text":"    for i in 0..x {","highlight_start":14,"highlight_end":18}],"label":null,"suggested_replacement":null,"expansion":null}}}],"children":[],"rendered":"error[E0019]: constant function contains unimplemented expression type\n  --> /checkout/src/test/ui/const-fn-error.rs:18:14\n   |\nLL |     for i in 0..x {\n   |              ^^^^\n\n"}
[00:43:56] {"message":"constant evaluation error","code":{"code":"E0080","explanation":"\nThis error indicates that the compiler was unable to sensibly evaluate an\nconstant expression that had to be evaluated. Attempting to divide by 0\nor causing integer overflow are two ways to induce this error. For example:\n\n```compile_fail,E0080\nenum Enum {\n    X = (1 << 500),\n    Y = (1 / 0)\n}\n```\n\nEnsure that the expressions given can be evaluated as the desired integer type.\nSee the FFI section of the Reference for more information about using a custom\ninteger type:\n\nhttps://doc.rust-lang.org/reference.html#ffi-attributes\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/const-fn-error.rs","byte_start":599,"byte_end":603,"line_start":18,"line_end":18,"column_start":14,"column_end":18,"is_primary":true,"text":[{"text":"    for i in 0..x {","highlight_start":14,"highlight_end":18}],"label":"calling non-const fn `<I as std::iter::IntoIterator><std::ops::Range<usize>>::into_iter`","suggested_replacement":null,"expansion":{"span":{"file_name":"/checkout/src/test/ui/const-fn-error.rs","byte_start":599,"byte_end":603,"line_start":18,"line_end":18,"column_start":14,"column_end":18,"is_primary":false,"text":[{"text":"    for i in 0..x {","highlight_start":14,"highlight_end":18}],"label":null,"suggested_replacement":null,"expansion":null},"macro_decl_name":"desugaring of `...`","def_site_span":{"file_name":"/checkout/src/test/ui/const-fn-error.rs","byte_start":599,"byte_end":603,"line_start":18,"line_end":18,"column_start":14,"column_end":18,"is_primary":false,"text":[{"text":"    for i in 0..x {","highlight_start":14,"highlight_end":18}],"label":null,"suggested_replacement":null,"expansion":null}}},{"file_name":"/checkout/src/test/ui/const-fn-error.rs","byte_start":773,"byte_end":777,"line_start":29,"line_end":29,"column_start":19,"column_end":23,"is_primary":false,"text":[{"text":"    let a : [i32; f(X)];","highlight_start":19,"highlight_end":23}],"label":"inside call to `f`","suggested_replacement":null,"expansion":null}],"children":[{"message":"for constant expression here","code":null,"level":"note","spans":[{"file_name":"/checkout/src/test/ui/const-fn-error.rs","byte_start":767,"byte_end":778,"line_start":29,"line_end":29,"column_start":13,"column_end":24,"is_primary":true,"text":[{"text":"    let a : [i32; f(X)];","highlight_start":13,"highlight_end":24}],"label":null,"suggested_replacement":null,"expansion":null}],"children":[],"rendered":null}],"rendered":"error[E0080]: constant evaluation error\n  --> /checkout/src/test/ui/const-fn-error.rs:18:14\n   |\nLL |     for i in 0..x {\n   |              ^^^^ calling non-const fn `<I as std::iter::IntoIterator><std::ops::Range<usize>>::into_iter`\n...\nLL |     let a : [i32; f(X)];\n   |                   ---- inside call to `f`\n   |\nnote: for constant expression here\n  --> /checkout/src/test/ui/const-fn-error.rs:29:13\n   |\nLL |     let a : [i32; f(X)];\n   |             ^^^^^^^^^^^\n\n"}
[00:43:56] {"message":"aborting due to 4 previous errors","code":null,"level":"error","spans":[],"children":[],"rendered":"error: aborting due to 4 previous errors\n\n"}
[00:43:56] {"message":"Some errors occurred: E0015, E0016, E0019, E0080.","code":null,"level":"","spans":[],"children":[],"rendered":"Some errors occurred: E0015, E0016, E0019, E0080.\n"}
[00:43:56] {"message":"For more information about an error, try `rustc --explain E0015`.","code":null,"level":"","spans":[],"children":[],"rendered":"For more information about an error, try `rustc --explain E0015`.\n"}
---
[00:43:56] 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"
[00:43:56] expected success, got: exit code: 101
[00:43:56]
[00:43:56]
[00:43:56] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[00:43:56] Build completed unsuccessfully in 0:02:23
[00:43:56] Makefile:58: recipe for target 'check' failed
[00:43:56] make: *** [check] Error 1

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)

[estebank]

@krk fix the contents of src/test/ui/const-fn-error.stderr. Move src/test/compile-fail/mir_check_nonconst.rs to src/test/ui/mir_check_nonconst.rs and create src/test/ui/mir_check_nonconst.stderr.

Once done, r=me.

[rust-highfive]

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.

Resolving deltas: 100% (616833/616833), completed with 4913 local objects.
---
[00:00:44] configure: rust.quiet-tests     := True
---
[00:40:35] .................................................................................i..................
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[00:48:05] ...i.............................................................................................test [run-pass] run-pass/mir_heavy_promoted.rs has been running for over 60 seconds
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[00:49:56] ....test [run-pass] run-pass/saturating-float-casts.rs has been running for over 60 seconds
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---
[00:55:18] error: /checkout/src/test/compile-fail/issue-43105.rs:13: unexpected error: '13:17: 13:22: calls in constants are limited to constant functions, tuple structs and tuple variants [E0015]'
[00:55:18]
[00:55:18] error: /checkout/src/test/compile-fail/issue-43105.rs:13: expected error not found: calls in constants are limited to constant functions, struct and enum constructors
[00:55:18]
[00:55:18] error: 1 unexpected errors found, 1 expected errors not found
[00:55:18] status: exit code: 101
[00:55:18] command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/compile-fail/issue-43105.rs" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail" "--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-43105.stage2-x86_64-unknown-linux-gnu" "-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-43105.stage2-x86_64-unknown-linux-gnu.aux" "-A" "unused"
[00:55:18] unexpected errors (from JSON output): [
[00:55:18]     Error {
[00:55:18]         line_num: 13,
[00:55:18]         kind: Some(
[00:55:18]             Error
[00:55:18]         ),
[00:55:18]     pile-fail/issue32829.rs:45: expected error not found: calls in statics are limited to constant functions, struct and enum
[00:55:18]
[00:55:18] error: /checkout/src/test/compile-fail/issue32829.rs:69: expected error not found: calls in statics are limited to constant functions, struct and enum
[00:55:18]
[00:55:18] error: 3 unexpected errors found, 3 expected errors not found
[00:55:18] status: exit code: 101
[00:55:18] command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/compile-fail/issue32829.rs" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail" "--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/issue32829.stage2-x86_64-unknown-linux-gnu" "-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/issue32829.stage2-x86_64-unknown-linux-gnu.aux" "-A" "unused"
[00:55:18] unexpected errors (from JSON output): [
[00:55:18]     Error {
[00:55:18]         line_num: 21,
[00:55:18]         kind: Some(
[00:55:18]             Error
[00:55:18]         ),
[00:55:18]         msg: "21:9: 21:18: calls in constants are limited to constant functions, tuple structs and tuple variants [E0015]"
---
[00:55:18]         msg: "45:9: 45:18: calls in statics are limited to constant functions, tuple structs and tuple variants [E0015]"
---
[00:55:18]         msg: "69:9: 69:18: calls in statics are limited to constant functions, tuple structs and tuple variants [E0015]"
---
[00:55:18]         msg: "calls in constants are limited to constant functions, struct and enum"
---
[00:55:18]         msg: "calls in statics are limited to constant functions, struct and enum"
---
[00:55:18]         msg: "calls in statics are limited to constant functions, struct and enum"
---
[00:55:18] 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"
[00:55:18] expected success, got: exit code: 101
[00:55:18]
[00:55:18]
[00:55:18] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[00:55:18] Build completed unsuccessfully in 0:15:48
[00:55:18] Makefile:58: recipe for target 'check' failed
[00:55:18] make: *** [check] Error 1
---
$ ls -lat $HOME/Library/Logs/DiagnosticReports/
ls: cannot access /home/travis/Library/Logs/DiagnosticReports/: No such file or directory

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)

[estebank]

@krk src/test/compile-fail/issue32829.rs and src/test/compile-fail/issue-43105.rs need to be updated as well.

[rust-highfive]

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.

Resolving deltas: 100% (616885/616885), completed with 4918 local objects.
---
[00:00:47] configure: rust.quiet-tests     := True
---
[00:05:28] tidy error: /checkout/src/test/compile-fail/issue32829.rs:23: line longer than 100 chars
[00:05:28] tidy error: /checkout/src/test/compile-fail/issue32829.rs:47: line longer than 100 chars
[00:05:28] tidy error: /checkout/src/test/compile-fail/issue32829.rs:71: line longer than 100 chars
[00:05:29] some tidy checks failed
[00:05:29]
[00:05:29]
[00:05:29] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/tidy" "/checkout/src" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "--no-vendor" "--quiet"
[00:05:29] expected success, got: exit code: 1
[00:05:29]
[00:05:29]
[00:05:29] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test src/tools/tidy
[00:05:29] Build completed unsuccessfully in 0:01:56
[00:05:29] Makefile:79: recipe for target 'tidy' failed
[00:05:29] make: *** [tidy] Error 1
---
$ ls -lat $HOME/Library/Logs/DiagnosticReports/
ls: cannot access /home/travis/Library/Logs/DiagnosticReports/: No such file or directory
travis_time:end:10a9d8e2:start=1524035008251556297,finish=1524035008258891418,duration=7335121
travis_fold:end:after_failure.2
travis_fold:start:after_failure.3
travis_time:start:0c496e0a
$ find $HOME/Library/Logs/DiagnosticReports -type f -name '*.crash' -not -name '*.stage2-*.crash' -not -name 'com.apple.CoreSimulator.CoreSimulatorService-*.crash' -exec printf travis_fold":start:crashlog\n\033[31;1m%s\033[0m\n" {} \; -exec head -750 {} \; -exec echo travis_fold":"end:crashlog \; || true
find: `/home/travis/Library/Logs/DiagnosticReports': No such file or directory
travis_time:end:0c496e0a:start=1524035008266569877,finish=1524035008273576047,duration=7006170
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:10a03616
$ dmesg | grep -i kill
[   11.244002] init: failsafe main process (1096) killed by TERM signal

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)

[estebank]

@bors r+ rollup

[bors]

📌 Commit b39b3a2 has been approved by estebank