only set non-ADT derive error once per attribute, not per trait #44055

zackmdavis · Aug 23, 2017

I found the expansion code very hard to follow, leaving me unsure as to whether this might somehow be done better, but this patch does give us the behavior requested in #43927 (up to exact choice of span; here, it's the entire attribute, not just the derive token).

(Note to GitHub robots: resolves #43927.)

r? @jseyfried

oli-obk · Aug 23, 2017

oli-obk reviewed Aug 23, 2017

View changes

oli-obk · Aug 23, 2017

src/libsyntax_ext/deriving/generic/mod.rs

@@ -428,8 +428,8 @@ impl<'a> TraitDef<'a> {
                        }
                    }
                    _ => {
-                        cx.span_err(mitem.span,
-                                    "`derive` may only be applied to structs, enums and unions");
+                        // This not-an-ADT case is an error, but it should have


so this branch should be bug!("non-ADT derive should have been caught during expansion")

Unfortunately, this will ICE: setting the span_err during expansion doesn't stop compilation from reaching this point. (But maybe it should??)

Can you add a debug! statement here then? Also add a comment pointing at libsyntax/ext/expand.rs:MacroExpand::expand() for the handling of this case.

Can you add a debug! statement here then?

Surprisingly, no: the libsyntax_ext crate doesn't have debug! in scope, and when I tried adding #[macro use] extern crate log; to lib.rs, we get "can't find crate for log". I don't understand what's going on there. (Added the expand filename comment pointer, though.)

oli-obk · Aug 23, 2017

You also need to update some compile-fail tests to your changes.

Click to expand

[00:47:25] [compile-fail] compile-fail/deriving-non-type.rs
[00:47:25] [compile-fail] compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs
[00:47:25] [compile-fail] compile-fail/feature-gate/issue-43106-gating-of-derive.rs
[00:47:25] [compile-fail] compile-fail/issue-36617.rs

[00:47:25] failures:
[00:47:25] 
[00:47:25] ---- [compile-fail] compile-fail/deriving-non-type.rs stdout ----
[00:47:25] 	
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:15: unexpected "error": '15:1: 15:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:18: unexpected "error": '18:1: 18:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:21: unexpected "error": '21:1: 21:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:24: unexpected "error": '24:1: 24:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:27: unexpected "error": '27:1: 27:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:30: unexpected "error": '30:1: 30:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:33: unexpected "error": '33:1: 33:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:36: unexpected "error": '36:1: 36:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:39: unexpected "error": '39:1: 39:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:15: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:18: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:21: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:24: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:27: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:30: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:33: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:36: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/deriving-non-type.rs:39: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: 9 unexpected errors found, 9 expected errors not found
[00:47:25] status: exit code: 101
[00:47:25] command: /checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc /checkout/src/test/compile-fail/deriving-non-type.rs -L /checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail --target=x86_64-unknown-linux-gnu --error-format json -L /checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail/deriving-non-type.stage2-x86_64-unknown-linux-gnu.compile-fail.libaux -A unused -C prefer-dynamic -o /checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail/deriving-non-type.stage2-x86_64-unknown-linux-gnu -Crpath -O -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers
[00:47:25] unexpected errors (from JSON output): [
[00:47:25]     Error {
[00:47:25]         line_num: 15,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "15:1: 15:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 18,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "18:1: 18:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 21,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "21:1: 21:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 24,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "24:1: 24:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 27,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "27:1: 27:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 30,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "30:1: 30:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 33,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "33:1: 33:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 36,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "36:1: 36:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 39,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "39:1: 39:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     }
[00:47:25] ]
[00:47:25] 
[00:47:25] not found errors (from test file): [
[00:47:25]     Error {
[00:47:25]         line_num: 15,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 18,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 21,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 24,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 27,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 30,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 33,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 36,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 39,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     }
[00:47:25] ]
[00:47:25] 
[00:47:25] thread '[compile-fail] compile-fail/deriving-non-type.rs' panicked at 'explicit panic', /checkout/src/tools/compiletest/src/runtest.rs:1133:12
[00:47:25] note: Run with `RUST_BACKTRACE=1` for a backtrace.
[00:47:25] 
[00:47:25] ---- [compile-fail] compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs stdout ----
[00:47:25] 	
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:15: unexpected "error": '15:1: 15:18: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:18: unexpected "error": '18:1: 18:17: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:21: unexpected "error": '21:17: 21:34: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:24: unexpected "error": '24:5: 24:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:40: unexpected "error": '40:5: 40:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:44: unexpected "error": '44:5: 44:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:15: expected error not found: cannot find derive macro `x3300` in this scope
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:18: expected error not found: cannot find derive macro `x3300` in this scope
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:21: expected error not found: cannot find derive macro `x3300` in this scope
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:24: expected error not found: cannot find derive macro `x3300` in this scope
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:28: expected error not found: cannot find derive macro `x3300` in this scope
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:32: expected error not found: cannot find derive macro `x3300` in this scope
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:36: expected error not found: cannot find derive macro `x3300` in this scope
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:40: expected error not found: cannot find derive macro `x3300` in this scope
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs:44: expected error not found: cannot find derive macro `x3300` in this scope
[00:47:25] 
[00:47:25] error: 6 unexpected errors found, 9 expected errors not found
[00:47:25] status: exit code: 101
[00:47:25] command: /checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs -L /checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail --target=x86_64-unknown-linux-gnu --error-format json -L /checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.stage2-x86_64-unknown-linux-gnu.compile-fail.libaux -A unused -C prefer-dynamic -o /checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail/feature-gate/issue-43106-gating-of-derive-2.stage2-x86_64-unknown-linux-gnu -Crpath -O -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers
[00:47:25] unexpected errors (from JSON output): [
[00:47:25]     Error {
[00:47:25]         line_num: 15,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "15:1: 15:18: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 18,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "18:1: 18:17: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 21,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "21:17: 21:34: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 24,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "24:5: 24:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 40,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "40:5: 40:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 44,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "44:5: 44:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     }
[00:47:25] ]
[00:47:25] 
[00:47:25] not found errors (from test file): [
[00:47:25]     Error {
[00:47:25]         line_num: 15,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "cannot find derive macro `x3300` in this scope"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 18,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "cannot find derive macro `x3300` in this scope"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 21,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "cannot find derive macro `x3300` in this scope"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 24,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "cannot find derive macro `x3300` in this scope"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 28,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "cannot find derive macro `x3300` in this scope"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 32,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "cannot find derive macro `x3300` in this scope"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 36,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "cannot find derive macro `x3300` in this scope"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 40,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "cannot find derive macro `x3300` in this scope"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 44,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "cannot find derive macro `x3300` in this scope"
[00:47:25]     }
[00:47:25] ]
[00:47:25] 
[00:47:25] thread '[compile-fail] compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs' panicked at 'explicit panic', /checkout/src/tools/compiletest/src/runtest.rs:1133:12
[00:47:25] 
[00:47:25] ---- [compile-fail] compile-fail/feature-gate/issue-43106-gating-of-derive.rs stdout ----
[00:47:25] 	
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive.rs:15: unexpected "error": '15:1: 15:18: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive.rs:18: unexpected "error": '18:1: 18:17: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive.rs:21: unexpected "error": '21:17: 21:34: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive.rs:24: unexpected "error": '24:5: 24:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive.rs:37: unexpected "error": '37:5: 37:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive.rs:41: unexpected "error": '41:5: 41:21: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive.rs:15: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive.rs:18: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive.rs:21: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive.rs:24: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive.rs:37: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive.rs:41: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: 6 unexpected errors found, 6 expected errors not found
[00:47:25] status: exit code: 101
[00:47:25] command: /checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc /checkout/src/test/compile-fail/feature-gate/issue-43106-gating-of-derive.rs -L /checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail --target=x86_64-unknown-linux-gnu --error-format json -L /checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail/feature-gate/issue-43106-gating-of-derive.stage2-x86_64-unknown-linux-gnu.compile-fail.libaux -A unused -C prefer-dynamic -o /checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail/feature-gate/issue-43106-gating-of-derive.stage2-x86_64-unknown-linux-gnu -Crpath -O -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers
[00:47:25] unexpected errors (from JSON output): [
[00:47:25]     Error {
[00:47:25]         line_num: 15,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "15:1: 15:18: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 18,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "18:1: 18:17: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 21,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "21:17: 21:34: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 24,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "24:5: 24:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 37,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "37:5: 37:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 41,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "41:5: 41:21: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     }
[00:47:25] thread 'main' panicked at 'Some tests failed', /checkout/src/tools/compiletest/src/main.rs:323:21
[00:47:25] ]
[00:47:25] 
[00:47:25] not found errors (from test file): [
[00:47:25]     Error {
[00:47:25]         line_num: 15,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 18,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 21,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 24,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 37,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     },
[00:47:25]     Error {
[00:47:25]         line_num: 41,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     }
[00:47:25] ]
[00:47:25] 
[00:47:25] thread '[compile-fail] compile-fail/feature-gate/issue-43106-gating-of-derive.rs' panicked at 'explicit panic', /checkout/src/tools/compiletest/src/runtest.rs:1133:12
[00:47:25] 
[00:47:25] ---- [compile-fail] compile-fail/issue-36617.rs stdout ----
[00:47:25] 	
[00:47:25] error: /checkout/src/test/compile-fail/issue-36617.rs:11: unexpected "error": '11:1: 11:17: `derive` may only be applied to structs, enums, and unions'
[00:47:25] 
[00:47:25] error: /checkout/src/test/compile-fail/issue-36617.rs:11: expected error not found: `derive` may only be applied to structs, enums and unions
[00:47:25] 
[00:47:25] error: 1 unexpected errors found, 1 expected errors not found
[00:47:25] status: exit code: 101
[00:47:25] command: /checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc /checkout/src/test/compile-fail/issue-36617.rs -L /checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail --target=x86_64-unknown-linux-gnu --error-format json -L /checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail/issue-36617.stage2-x86_64-unknown-linux-gnu.compile-fail.libaux -A unused -C prefer-dynamic -o /checkout/obj/build/x86_64-unknown-linux-gnu/test/compile-fail/issue-36617.stage2-x86_64-unknown-linux-gnu -Crpath -O -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers
[00:47:25] unexpected errors (from JSON output): [
[00:47:25]     Error {
[00:47:25]         line_num: 11,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "11:1: 11:17: `derive` may only be applied to structs, enums, and unions"
[00:47:25]     }
[00:47:25] ]
[00:47:25] 
[00:47:25] not found errors (from test file): [
[00:47:25]     Error {
[00:47:25]         line_num: 11,
[00:47:25]         kind: Some(
[00:47:25]             Error
[00:47:25]         ),
[00:47:25]         msg: "`derive` may only be applied to structs, enums and unions"
[00:47:25]     }
[00:47:25] ]
[00:47:25] 
[00:47:25] thread '[compile-fail] compile-fail/issue-36617.rs' panicked at 'explicit panic', /checkout/src/tools/compiletest/src/runtest.rs:1133:12
[00:47:25] 
[00:47:25] 
[00:47:25] failures:
[00:47:25]     [compile-fail] compile-fail/deriving-non-type.rs
[00:47:25]     [compile-fail] compile-fail/feature-gate/issue-43106-gating-of-derive-2.rs
[00:47:25]     [compile-fail] compile-fail/feature-gate/issue-43106-gating-of-derive.rs
[00:47:25]     [compile-fail] compile-fail/issue-36617.rs
[00:47:25] 
[00:47:25] test result: �[31mFAILED�(B�[m. 2715 passed; 4 failed; 13 ignored; 0 measured; 0 filtered out

jseyfried · Aug 23, 2017

jseyfried reviewed Aug 23, 2017

View changes

jseyfried · Aug 23, 2017

src/libsyntax/ext/expand.rs

@@ -282,6 +282,22 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                    let expansion = self.expand_invoc(invoc, ext);
                    self.collect_invocations(expansion, &[])
                } else if let InvocationKind::Attr { attr: None, traits, item } = invoc.kind {
+                    if let Annotatable::Item(ref item) = item {


Could we also error on Annotatable::TraitItem and Annotatable::ImplItem here and then also get rid of the other corresponding error in src/libsyntax_ext/deriving/generic/mod.rs? e.g.

let derive_allowed = match item { Annotatable::Item(ref item) => match item.node { ast::ItemKind::Struct(..) | ast::ItemKind::Enum(..) | ast::ItemKind::Union(..) => true, _ => false, _ => false, }; if !derive_allowed { // error }

jseyfried · Aug 23, 2017

@zackmdavis looks good! r=me with @oli-obk's comment addressed.

Derive expansion is still split somewhat between libsyntax and libsyntax_ext so it can be confusing. We're trying to move the expansion logic out of libsyntax_ext to libsyntax; this PR is done well and moves us in the right direction :)

zackmdavis · Aug 27, 2017

Updated. Travis error appears spurious (just one macOS subjob failed, and its terminal log says that git fetch failed).

There are two potential concerns, though:

The code in libsyntax_ext/deriving/generic/mod.rs still runs, so we can't put an assertion there unless we somehow stop compilation earlier.
As revealed by the compile-fail tests, if the non-ADT-derive error occurs, then we don't get to see any derive-macro-not-found errors (which will surface the next time the user attempts to compile after fixing the erroneous non-ADT derives). This isn't necessarily a blocker (it's pretty ordinary for errors in one pass to overshadow others), but it wasn't intended and I don't understand why it's happening.

eddyb · Aug 30, 2017

@zackmdavis Restarted the dummy macOS build, should be green in a few minutes.

arielb1 · Sep 5, 2017

@zackmdavis do you think we should land this as is, or are you interested in perfecting it? If that, are you still interested in working on this? Just a friendly ping too make sure it isn't getting lost.

zackmdavis · Sep 6, 2017

@arielb1 My disposition is to merge as-is (the reservations bulleted in my previous comment being minor IMO), but if someone were to argue that it's important to preserve the exact error behavior specified in the original compile-fail/issue-43106-gating-of-derive-2.rs, I would respect that judgment, too.

carols10cents · Sep 11, 2017

@jseyfried sounds like this is in your court for review. what do you think?

carols10cents · Sep 18, 2017

ping @jseyfried @rust-lang/compiler for review please!

estebank · Sep 18, 2017

estebank reviewed Sep 18, 2017

View changes

Other than a few nitpicks I'm r+ too.

estebank · Sep 18, 2017

src/libsyntax/ext/expand.rs

+                            .find(|attr| attr.check_name("derive"))
+                            .expect("`derive` attribute should exist").span;
+                        self.cx.span_err(span,
+                                         "`derive` may only be applied to structs, enums, \


Can you keep the existing output and avoid the oxford comma? Not because I'm against it but I'd prefer to keep this change small (so it doesn't affect compile-fail/deriving-non-type.rs at all).

During the impl period I'm going to audit all the existing diagnostic output in order to identify current conventions to write them down. Doing this I fully expect to find inconsistent wording and will try to reach consensus for them.

I trust that the community will affirm the correctness of the serial comma at that time.

estebank · Sep 18, 2017

src/test/ui/span/issue-43927-non-ADT-derive.stderr

+  --> $DIR/issue-43927-non-ADT-derive.rs:13:1
+   |
+13 | #![derive(Debug, PartialEq, Eq)] // should be an outer attribute!
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


This is a great example of a case where a note pointing out that this derive is being applied to the outer context instead of the struct immediately after would be beneficial. If you don't want to add that on this PR, could you please file a ticket for it?

It could be something along the lines of

error: `derive` may only be applied to structs, enums, and unions --> $DIR/issue-43927-non-ADT-derive.rs:13:1 | 13 | #![derive(Debug, PartialEq, Eq)] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ derive cannot be applied to outer mod note: as it is written, the derive is applied to the outer scope, did you mean to apply it to the next element? | 13 | #[derive(Debug, PartialEq, Eq)] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

estebank · Sep 18, 2017

src/libsyntax_ext/deriving/generic/mod.rs

@@ -428,8 +428,8 @@ impl<'a> TraitDef<'a> {
                        }
                    }
                    _ => {
-                        cx.span_err(mitem.span,
-                                    "`derive` may only be applied to structs, enums and unions");
+                        // This not-an-ADT case is an error, but it should have


Can you add a debug! statement here then? Also add a comment pointing at libsyntax/ext/expand.rs:MacroExpand::expand() for the handling of this case.

jseyfried · Sep 20, 2017

r=me with @estebank's comment addressed.

zackmdavis · Sep 22, 2017

(force-pushed)

We no longer add a serial comma to the message, leaving that to a future error-message auditing pass.
"error set earlier" comments in libsyntax_ext note file/function where
- unfortunately, the debug! macro isn't available in libsyntax_ext (and trying to add the log crate didn't work), so the reviewer suggestion to use that was not taken in this revision
another commit adds a suggestion to use an outer attribute (#, not #!) in the case where the offending attribute was an inner

estebank · Sep 23, 2017

@bors r=jseyfried

bors · Sep 23, 2017

📌 Commit 083f053 has been approved by jseyfried

bors · Sep 23, 2017

⌛️ Testing commit 083f053 with merge 9ad67e9...

bors · Sep 23, 2017

☀️ Test successful - status-appveyor, status-travis
Approved by: jseyfried
Pushing 9ad67e9 to master...

Havvy · Sep 23, 2017

💟

rust-highfive assigned jseyfried Aug 23, 2017

aidanhs added the S-waiting-on-author label Aug 23, 2017

zackmdavis force-pushed the zackmdavis:condensed_non-ADT_derive_error branch from 6a9d0e1 to 9d4c171 Aug 26, 2017

carols10cents added S-waiting-on-review and removed S-waiting-on-author labels Sep 11, 2017

zackmdavis force-pushed the zackmdavis:condensed_non-ADT_derive_error branch from 9d4c171 to 083f053 Sep 22, 2017

bors merged commit 083f053 into rust-lang:master Sep 23, 2017
2 checks passed

2 checks passed

continuous-integration/travis-ci/pr The Travis CI build passed
Details

homu Test successful
Details

zackmdavis deleted the zackmdavis:condensed_non-ADT_derive_error branch Jan 13, 2018

rust-lang/rust

Join GitHub today

only set non-ADT derive error once per attribute, not per trait #44055

Conversation

zackmdavis commented Aug 23, 2017

rust-highfive assigned jseyfried Aug 23, 2017

oli-obk reviewed Aug 23, 2017 View changes

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

oli-obk commented Aug 23, 2017

jseyfried reviewed Aug 23, 2017 View changes

This comment has been minimized.

This comment has been minimized.

jseyfried commented Aug 23, 2017 • edited

aidanhs added the S-waiting-on-author label Aug 23, 2017

zackmdavis force-pushed the zackmdavis:condensed_non-ADT_derive_error branch from 6a9d0e1 to 9d4c171 Aug 26, 2017

This comment has been minimized.

zackmdavis commented Aug 27, 2017

This comment has been minimized.

eddyb commented Aug 30, 2017

This comment has been minimized.

arielb1 commented Sep 5, 2017

This comment has been minimized.

zackmdavis commented Sep 6, 2017

carols10cents added S-waiting-on-review and removed S-waiting-on-author labels Sep 11, 2017

This comment has been minimized.

carols10cents commented Sep 11, 2017

This comment has been minimized.

carols10cents commented Sep 18, 2017

estebank reviewed Sep 18, 2017 View changes

estebank left a comment

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

jseyfried commented Sep 20, 2017 • edited

zackmdavis added some commits Aug 23, 2017

zackmdavis force-pushed the zackmdavis:condensed_non-ADT_derive_error branch from 9d4c171 to 083f053 Sep 22, 2017

This comment has been minimized.

zackmdavis commented Sep 22, 2017 • edited

This comment has been minimized.

estebank commented Sep 23, 2017

This comment has been minimized.

bors commented Sep 23, 2017

This comment has been minimized.

bors commented Sep 23, 2017

bors added a commit that referenced this pull request Sep 23, 2017

This comment has been minimized.

bors commented Sep 23, 2017

Hide details View details bors merged commit 083f053 into rust-lang:master Sep 23, 2017 2 checks passed

2 checks passed

This comment has been minimized.

Havvy commented Sep 23, 2017

zackmdavis deleted the zackmdavis:condensed_non-ADT_derive_error branch Jan 13, 2018

oli-obk reviewed Aug 23, 2017

View changes

jseyfried reviewed Aug 23, 2017

View changes

jseyfried commented Aug 23, 2017 •

edited

zackmdavis force-pushed the zackmdavis:condensed_non-ADT_derive_error branch from `6a9d0e1` to `9d4c171` Aug 26, 2017

estebank reviewed Sep 18, 2017

View changes

jseyfried commented Sep 20, 2017 •

edited

zackmdavis force-pushed the zackmdavis:condensed_non-ADT_derive_error branch from `9d4c171` to `083f053` Sep 22, 2017

zackmdavis commented Sep 22, 2017 •

edited

bors merged commit `083f053` into rust-lang:master Sep 23, 2017
2 checks passed