Provide existing ref suggestions for more E0308 errors #51822

estebank · 2018-06-26T18:41:51Z

No description provided.

rust-highfive · 2018-06-26T18:42:03Z

(rust_highfive has picked a reviewer for you, use r? to override)

nikomatsakis · 2018-06-26T21:21:58Z

src/librustc_typeck/check/demand.rs

@@ -342,11 +329,14 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                // a macro; if so, it's hard to extract the text and make a good
                // suggestion, so don't bother.)
                if self.infcx.can_sub(self.param_env, checked, &expected).is_ok() &&
-                   expr.span.ctxt().outer().expn_info().is_none() {
+                   sp.ctxt().outer().expn_info().is_none() {


since we switched to call_site_if_macro here, do we know that is_none() will always be true?

nikomatsakis · 2018-06-26T21:43:31Z

r=me modulo the nit above; if you think we can simplify, seems good, otherwise it's fine as is

rust-highfive · 2018-06-28T01:38:08Z

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.

/usr/local/lib/python2.7/dist-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:122: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. You can upgrade to a newer version of Python to solve this. For more information, see https://urllib3.readthedocs.io/en/latest/security.html#insecureplatformwarning.
  InsecurePlatformWarning
/usr/local/lib/python2.7/dist-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:122: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. You can upgrade to a newer version of Python to solve this. For more information, see https://urllib3.readthedocs.io/en/latest/security.html#insecureplatformwarning.
  InsecurePlatformWarning
  Downloading https://files.pythonhosted.org/packages/f3/04/ef69353b3bdbc6ddb9de24291039dc06c33feb0e51ed73f5f3be707ae035/awscli-1.15.47-py2.py3-none-any.whl (1.3MB)
    0% |▎                               | 10kB 11.1MB/s eta 0:00:01
    1% |▌                               | 20kB 1.8MB/s eta 0:00:01
    2% |▊                               | 30kB 2.1MB/s eta 0:00:01
    3% |█                               | 40kB 1.9MB/s eta 0:00:01
---
Check compiletest suite=ui mode=ui (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
[00:46:46] 
[00:46:46] running 1532 tests
[00:46:52] .................................................................................................i..
[00:46:58] ............................................................i..........F............................
[00:47:06] ....................................................................................................
[00:47:09] ....................................................................................................
[00:47:13] ....................................................................................................
[00:47:18] ....................................................................................................
---
[00:47:46] .........i..........................................................................................
[00:47:52] ....................................................................................................
[00:47:57] ....................................................................................................
[00:48:07] status: exit code: 101
[00:48:07] command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/deref-suggestion.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/deref-suggestion/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/deref-suggestion/auxiliary" "-A" "unused"
[00:48:07] ------------------------------------------
[00:48:07] 
[00:48:07] ------------------------------------------
[00:48:07] stderr:
[00:48:07] stderr:
[00:48:07] ------------------------------------------
[00:48:07] {"message":"mismatched types","code":{"code":"E0308","explanation":"\nThis error occurs when the compiler was unable to infer the concrete type of a\nvariable. It can occur for several cases, the most common of which is a\nmismatch in the expected type that the compiler inferred for a variable's\ninitializing expression, and the actual type explicitly assigned to the\nvariable.\n\nFor example:\n\n```compile_fail,E0308\nlet x: i32 = \"I am not a number!\";\n//     ~~~   ~~~~~~~~~~~~~~~~~~~~\n//      |             |\n//      |    initializing expression;\n//      |    compiler infers type `&str`\n//      |\n//    type `i32` assigned to variable `x`\n```\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/deref-suggestion.rs","byte_start":596,"byte_end":597,"line_start":18,"line_end":18,"column_start":9,"column_end":10,"is_primary":true,"text":[{"text":"    foo(s); //~ ERROR mismatched types","highlight_start":9,"highlight_end":10}],"label":"expected struct `std::string::String`, found reference","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`\n   found type `&std::string::String`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"try using a conversion method","code":null,"level":"help","spans":[{"file_name":"/checkout/src/test/ui/deref-suggestion.rs","byte_start":596,"byte_end":597,"line_start":18,"line_end":18,"column_start":9,"column_end":10,"is_primary":true,"text":[{"text":"    foo(s); //~ ERROR mismatched types","highlight_start":9,"highlight_end":10}],"label":null,"suggested_replacement":"s.to_string()","suggestion_applicability":"Unspecified","expansion":null}],"children":[],"rendered":null}],"rendered":"error[E0308]: mismatched types\n  --> /checkout/src/test/ui/deref-suggestion.rs:18:9\n   |\nLL |     foo(s); //~ ERROR mismatched types\n   |         ^\n   |         |\n   |         expected struct `std::string::String`, found reference\n   |         help: try using a conversion method: `s.to_string()`\n   |\n   = note: expected type `std::string::String`\n              found type `&std::string::String`\n\n"}
[00:48:07] {"message":"mismatched types","code":{"code":"E0308","explanation":"\nThis error occurs when the compiler was unable to infer the concrete type of a\nvariable. It can occur for several cases, the most common of which is a\nmismatch in the expected type that the compiler inferred for a variable's\ninitializing express:"    foo(&\"aaa\".to_owned()); //~ ERROR mismatched types","highlight_start":9,"highlight_end":26}],"label":null,"suggested_replacement":"\"aaa\".to_owned()","suggestion_applicability":"Unspecified","expansion":null}],"children":[],"rendered":null}],"rendered":"error[E0308]: mismatched types\n  --> /checkout/src/test/ui/deref-suggestion.rs:30:9\n   |\nLL |     foo(&\"aaa\".to_owned()); //~ ERROR mismatched types\n   |         ^^^^^^^^^^^^^^^^^\n   |         |\n   |         expected struct `std::string::String`, found reference\n   |         help: consider removing the borrow: `\"aaa\".to_owned()`\n   |\n   = note: expected type `std::string::String`\n              found type `&std::string::String`\n\n"}
[00:48:07] {"message":"mismatched types","code":{"code":"E0308","explanation":"\nThis error occurs when the compiler was unable to infer the concrete type of a\nvariable. It can occur for several cases, the most common of which is a\nmismatch in the expected type that the compiler inferred for a variable's\ninitializing expression, and the actual type explicitly assigned to the\nvariable.\n\nFor example:\n\n```compile_fail,E0308\nlet x: i32 = \"I am not a number!\";\n//     ~~~   ~~~~~~~~~~~~~~~~~~~~\n//      |             |\n//      |    initializing expression;\n//      |    compiler infers type `&str`\n//      |\n//    type `i32` assigned to variable `x`\n```\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/deref-suggestion.rs","byte_start":846,"byte_end":867,"line_start":31,"line_end":31,"column_start":9,"column_end":30,"is_primary":true,"text":[{"text":"    foo(&mut \"aaa\".to_owned()); //~ ERROR mismatched types","highlight_start":9,"highlight_end":30}],"label":"expected struct `std::string::String`, found mutable reference","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`\n   found type `&mut std::string::String`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"consider removing the borrow","code":null,"level":"help","spans":[{"file_name":"/checkout/src/test/ui/deref-suggestion.rs","byte_start":846,"byte_end":867,"line_start":31,"line_end":31,"column_start":9,"column_end":30,"is_primary":true,"text":[{"text":"    foo(&mut \"aaa\".to_owned()); //~ ERROR mismatched types","highlight_start":9,"highlight_end":30}],"label":null,"suggested_replacement":"\"aaa\".to_owned()","suggestion_applicability":"Unspecified","expansion":null}],"children":[],"rendered":null}],"rendered":"error[E0308]: mismatched types\n  --> /checkout/src/test/ui/deref-suggestion.rs:31:9\n   |\nLL |     foo(&mut \"aaa\".to_owned()); //~ ERROR mismatched types\n   |         ^^^^^^^^^^^^^^^^^^^^^\n   |         |\n   |         expected struct `std::string::String`, found mutable reference\n   |         help: consider removing the borrow: `\"aaa\".to_owned()`\n   |\n   = note: expected type `std::string::String`\n              found type `&mut std::string::String`\n\n"}
[00:48:07] {"message":"mismatched types","code":{"code":"E0308","explanation":"\nThis error occurs when the compiler was unable to infer the concrete type of a\nvariable. It can occur for several cases, the most common of which is a\nmismatch in the expected type that the compiler inferred for a variable's\ninitializing expression, and the actual type explicitly assigned to the\nvariable.\n\nFor example:\n\n```compile_fail,E0308\nlet x: i32 = \"I am not a number!\";\n//     ~~~   ~~~~~~~~~~~~~~~~~~~~\n//      |             |\n//      |    initializing expression;\n//      |    compiler infers type `&str`\n//      |\n//    type `i32` assigned to variable `x`\n```\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/deref-suggestion.rs","byte_start":508,"byte_end":511,"line_start":12,"line_end":12,"column_start":20,"column_end":23,"is_primary":true,"text":[{"text":"    ($x:expr) => { &$x } //~ ERROR mismatched types","highlight_start":20,"highlight_end":23}],"label":"expected u32, found &{integer}","suggested_replacement":null,"suggestion_applicability":null,"expansion":{"span":{"file_name":"/checkout/src/test/ui/deref-suggestion.rs","byte_start":906,"byte_end":916,"line_start":32,"line_end":32,"column_start":10,"column_end":20,"is_primary":false,"text":[{"text":"    foo3(borrow!(0));","highlight_start":10,"highlight_end":20}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null},"macro_decl_name":"borrow!","def_site_span":{"file_name":"/checkout/src/test/ui/deref-suggestion.rs","byte_start":467,"byte_end":542,"line_start":11,"line_end":13,"column_start":1,"column_end":2,"is_primary":false,"text":[{"text":"macro_rules! borrow {","highlight_start":1,"highlight_end":22},{"text":"    ($x:expr) => { &$x } //~ ERROR mismatched types","highlight_start":1,"highlight_end":52},{"text":"}","highlight_start":1,"highlight_end":2}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null}}}],"children":[{"message":"expected type `u32`\n   found type `&{integer}`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"consider removing the borrow","code":null,"level":"help","spans":[{"file_name":"/checkout/src/test/ui/deref-suggestion.rs","byte_start":508,"byte_end":511,"line_start":12,"line_end":12,"column_start":20,"column_end":23,"is_primary":true,"text":[{"text":"    ($x:expr) => { &$x } //~ ERROR mismatched types","highlight_start":20,"highlight_end":23}],"label":null,"suggested_replacement":"0","suggestion_applicability":"Unspecified","expansion":{"span":{"file_name":"/checkout/src/test/ui/deref-suggestion.rs","byte_start":906,"byte_end":916,"line_start":32,"line_end":32,"column_start":10,"column_end":20,"is_primary":false,"text":[{"text":"    foo3(borrow!(0));","highlight_start":10,"highlight_end":20}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null},"macro_decl_name":"borrow!","def_site_span":{"file_name":"/checkout/src/test/ui/deref-suggestion.rs","byte_start":467,"byte_end":542,"line_start":11,"line_end":13,"column_start":1,"column_end":2,"is_primary":false,"text":[{"text":"macro_rules! borrow {","highlight_start":1,"highlight_end":22},{"text":"    ($x:expr) => { &$x } //~ ERROR mismatched types","highlight_start":1,"highlight_end":52},{"text":"}","highlight_start":1,"highlight_end":2}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null}}}],"children":[],"rendered":null}],"rendered":"error[E0308]: mismatched types\n  --> /checkout/src/test/ui/deref-suggestion.rs:12:20\n   |\nLL |     ($x:expr) => { &$x } //~ ERROR mismatched types\n   |                    ^^^\n   |                    |\n   |                    expected u32, found &{integer}\n   |                    help: consider removing the borrow: `0`\n...\nLL |     foo3(borrow!(0));\n   |          ---------- in this macro invocation\n   |\n   = note: expected type `u32`\n              found type `&{integer}`\n\n"}
[00:48:07] {"message":"aborting due to 5 previous errors","code":null,"level":"error","spans":[],"children":[],"rendered":"error: aborting due to 5 previous errors\n\n"}
[00:48:07] {"message":"For more information about this error, try `rustc --explain E0308`.","code":null,"level":"","spans":[],"children":[],"rendered":"For more information about this error, try `rustc --explain E0308`.\n"}
[00:48:07] ------------------------------------------
[00:48:07] 
[00:48:07] thread '[ui] ui/deref-suggestion.rs' panicked at 'explicit panic', tools/compiletest/src/runtest.rs:3139:9
[00:48:07] note: Run with `RUST_BACKTRACE=1` for a backtrace.
---
travis_time:end:071f36d0:start=1530149885150194183,finish=1530149885158686354,duration=8492171
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:0304de1a
$ head -30 ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
head: cannot open ‘./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers’ for reading: No such file or directory
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:12325830
$ dmesg | grep -i kill

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)

nikomatsakis

seems good, but travis is unhappy now? r=me modulo travis and below nit

nikomatsakis · 2018-06-28T15:45:27Z

src/librustc_typeck/check/demand.rs

@@ -328,8 +328,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                // (But, also check check the `expn_info()` to see if this is
                // a macro; if so, it's hard to extract the text and make a good
                // suggestion, so don't bother.)
-                if self.infcx.can_sub(self.param_env, checked, &expected).is_ok() &&
-                   sp.ctxt().outer().expn_info().is_none() {


(maybe we should make it assert?)

No, I think it'd be better to revert that last commit. The checks are in different spans and we should only suggest if both spans are outside of macros. Originally I thought that it would make sense to suggest if the macro was local (meaning that the user could do something about it), but in that case the span already points at the problematic place, and I will assume that anyone using macros would have enough knowledge of the language to deal with an E0308 between u32 and &{integer}. What do you think?

[00:48:07] 50 --> $DIR/deref-suggestion.rs:12:20 [00:48:07] 51 | [00:48:07] 52 LL | ($x:expr) => { &$x } //~ ERROR mismatched types [00:48:07] - | ^^^ expected u32, found &{integer} [00:48:07] + | ^^^ [00:48:07] + | | [00:48:07] + | expected u32, found &{integer} [00:48:07] + | help: consider removing the borrow: `0` [00:48:07] 54 ... [00:48:07] 55 LL | foo3(borrow!(0)); [00:48:07] 56 | ---------- in this macro invocation

estebank · 2018-06-28T18:18:01Z

@bors r=nikomatsakis

Assuming that I'm being reasonable with #51822 (comment).

estebank · 2018-06-28T18:37:53Z

@bors r=nikomatsakis

bors · 2018-06-28T18:37:54Z

📌 Commit 54a04b3 has been approved by nikomatsakis

Mark-Simulacrum · 2018-06-28T22:06:06Z

@bors rollup

Provide existing ref suggestions for more E0308 errors

@ghost

Rollup of 6 pull requests Successful merges: - #51636 (Refactor error reporting of constants) - #51765 (Use assert_eq! in copy_from_slice) - #51822 (Provide existing ref suggestions for more E0308 errors) - #51839 (Detect overflows of non u32 shifts) - #51868 (Remove process::id from 'Stabilized APIs' in 1.27.0 release notes) - #51875 (Explicitely disable WASM code generation for Emscripten) Failed merges: r? @ghost

rust-highfive assigned nikomatsakis Jun 26, 2018

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estebank force-pushed the suggest-more branch 2 times, most recently from d12eaa0 to d2161c7 Compare June 28, 2018 17:44

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estebank force-pushed the suggest-more branch from d2161c7 to 527255a Compare June 28, 2018 18:16

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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 28, 2018

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Provide existing ref suggestions for more E0308 errors

54a04b3

estebank force-pushed the suggest-more branch from 527255a to 54a04b3 Compare June 28, 2018 18:37

Mark-Simulacrum added a commit to Mark-Simulacrum/rust that referenced this pull request Jun 28, 2018

Rollup merge of rust-lang#51822 - estebank:suggest-more, r=nikomatsakis

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Provide existing ref suggestions for more E0308 errors

Mark-Simulacrum mentioned this pull request Jun 28, 2018

Rollup of 6 pull requests #51884

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bors merged commit 54a04b3 into rust-lang:master Jun 29, 2018

csmoe mentioned this pull request Jul 28, 2018

bad suggestion on 'assert_eq!(3i32, &3i32)' #52783

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Provide existing ref suggestions for more E0308 errors #51822

Provide existing ref suggestions for more E0308 errors #51822

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Provide existing ref suggestions for more E0308 errors #51822

Provide existing ref suggestions for more E0308 errors #51822

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