Compiler Unexpectedly Panicked, call function with wrong number of arguments

[adrian-budau]

First of all, this only happens on nightly

rustc --version --verbose
binary: rustc
commit-hash: 97520ccb101609af63f29919bb0a39115269c89e
commit-date: 2018-01-21
host: x86_64-unknown-linux-gnu
release: 1.25.0-nightly
LLVM version: 4.0

I tried to make the code as simple as possible, so it might look like something no sane person would write

pub struct Foo {
    foo: Option<i32>,
}

impl Foo {
    pub fn new(foo: Option<i32>, _: ()) -> Foo {
        Foo { foo }
    }

    pub fn map(self) -> Option<Foo> {
        self.foo.map(Foo::new)
    }
}

This is what i get as output

thread 'rustc' panicked at 'non-FnLike node found: NodeImplItem(ImplItem { id: NodeId(14), name: new, hir_id: HirId { owner: DefIndex(0:6), local_id: ItemLocalId(0) }, vis: Public, defaultness: Final, attrs: [], generics: Generics { params: [], where_clause: WhereClause { id: NodeId(15), predicates: [] }, span: src/lib.rs:1:1: 1:1 }, node: Method(MethodSig { unsafety: Normal, constness: NotConst, abi: Rust, decl: FnDecl { inputs: [type(Option<i32>), type(())], output: Return(type(Foo)), variadic: false, has_implicit_self: false } }, BodyId { node_id: NodeId(41) }), span: src/run_info.rs:6:5: 8:6 })', librustc/traits/error_reporting.rs:837:13
note: Run with `RUST_BACKTRACE=1` for a backtrace.

[emilio]

I also hit this, but my test-case was "apply this patch to servo", so I'm glad you had a reduced test-case already, thanks!

[dtolnay]

Stable: rustc 1.23.0 (766bd11 2018-01-01)

error[E0593]: function is expected to take 1 argument, but it takes 2 arguments
  --> src/main.rs:21:18
   |
11 |         self.foo.map(Foo::new)
   |                  ^^^ expected function that takes 1 argument

Beta: rustc 1.24.0-beta.8 (ed9751a 2018-01-23)

error[E0593]: function is expected to take 1 argument, but it takes 2 arguments
  --> src/main.rs:11:18
   |
6  |     pub fn new(foo: Option<i32>, _: ()) -> Foo {
   |     ------------------------------------------ takes 2 arguments
...
11 |         self.foo.map(Foo::new)
   |                  ^^^ expected function that takes 1 argument

[nikomatsakis]

cc @rust-lang/infra -- any chance we could bisect this down to a PR?

[nikomatsakis]

triage: P-high

Regression. Should be an easy fix.

[kennytm]

Bisecting between b65f0be...a0dcecf.

Script:

#!/bin/sh
$RUSTC_RELATIVE 1.rs 2>&1 | grep FnLike

Bisection result:

$ target/release/bisect --preserve --test test.sh --start b65f0bedd2f22d9661ecb7092f07746dc2ccfb0d --end a0dcecff90c45ad5d4eb60859e22bb3f1b03842a
INFO:rust_sysroot: Getting commits from the git checkout in b65f0bedd2f22d9661ecb7092f07746dc2ccfb0d...a0dcecff90c45ad5d4eb60859e22bb3f1b03842a
INFO:rust_sysroot: Received 93 commits
Searching in 93 commits; about 7 steps
thread 'rustc' panicked at 'non-FnLike node found: NodeImplItem(ImplItem { id: NodeId(13), name: new, hir_id: HirId { owner: DefIndex(0:5), local_id: ItemLocalId(0) }, vis: Public, defaultness: Final, attrs: [], generics: Generics { params: [], where_clause: WhereClause { id: NodeId(14), predicates: [] }, span: 1.rs:1:1: 1:1 }, node: Method(MethodSig { unsafety: Normal, constness: NotConst, abi: Rust, decl: FnDecl { inputs: [type(Option<i32>), type(())], output: Return(type(Foo)), variadic: false, has_implicit_self: false } }, BodyId { node_id: NodeId(40) }), span: 1.rs:6:5: 8:6 })', librustc/traits/error_reporting.rs:837:13
thread 'rustc' panicked at 'non-FnLike node found: NodeImplItem(ImplItem { id: NodeId(13), name: new, hir_id: HirId { owner: DefIndex(0:5), local_id: ItemLocalId(0) }, vis: Public, defaultness: Final, attrs: [], generics: Generics { params: [], where_clause: WhereClause { id: NodeId(14), predicates: [] }, span: 1.rs:1:1: 1:1 }, node: Method(MethodSig { unsafety: Normal, constness: NotConst, abi: Rust, decl: FnDecl { inputs: [type(Option<i32>), type(())], output: Return(type(Foo)), variadic: false, has_implicit_self: false } }, BodyId { node_id: NodeId(40) }), span: 1.rs:6:5: 8:6 })', librustc/traits/error_reporting.rs:837:13
searched commits b65f0bedd2f22d9661ecb7092f07746dc2ccfb0d through a0dcecff90c45ad5d4eb60859e22bb3f1b03842a
regression in 76; Some(Commit { sha: "8d3e93beae9562f8b32b7f82c3824389f6ac5bad", date: 2018-01-21T06:32:03Z, summary: "Auto merge of #47622 - GuillaumeGomez:rollup, r=GuillaumeGomez" })

Actual cause is #47573, cc @estebank.

[estebank]

Confirmed, panic introduced in that PR. Will submit for review once local test run completes.

Sorry about this, I failed to account for impl methods.

---

Fix: #47747. I've kept the panic there, as this code should never be called with a non-fn element and would want it to complain loudly if it happens, but if an ICE ever happens again, we can fall through silently (at the very least in stable) as only con of doing so is having no label in the original item's span.

[CAD97]

@estebank ICE still occurs with NodeTraitItem (trait default fn)

trait T {
    fn f(&self, _: ()) {
        None::<()>.map(Self::f);
    }
}

Stack Trace

thread 'rustc' panicked at 'non-FnLike node found: NodeTraitItem(TraitItem { id: NodeId(6), name: f, hir_id: HirId { owner: DefIndex(0:4), local_id: ItemLocalId(0) }, attrs: [], generics: Generics { params: [], where_clause: WhereClause { id: NodeId(7), predicates: [] }, span: src\main.rs:1:1: 1:1 }, node: Method(MethodSig { unsafety: Normal, constness: NotConst, abi: Rust, decl: FnDecl { inputs: [type(&Self), type(())], output: DefaultReturn(src\main.rs:2:24: 2:24), variadic: false, has_implicit_self: true } }, Provided(BodyId { node_id: NodeId(25) })), span: src\main.rs:2:5: 4:6 })', librustc\traits\error_reporting.rs:846:18
stack backtrace:
   0:     0x7ffedcc846dd - std::rt::lang_start_internal::h6a4891cd6ad9df3d
   1:     0x7ffedcc872ef - std::fs::FileType::is_dir::hf1c2aa54924656a2
   2:     0x7ffedcc9082f - std::panicking::Location::column::hdc2cb9a904b38b88
   3:     0x7ffedcc904d5 - std::panicking::Location::column::hdc2cb9a904b38b88
   4:     0x7ffedcc90dfc - std::panicking::rust_panic_with_hook::h722955029fa85c2e
   5:     0x7ffedcc90c00 - std::panicking::begin_panic_fmt::hdf8109b479eeb360
   6:     0x7ffedcc90b51 - std::panicking::begin_panic_fmt::hdf8109b479eeb360
   7:     0x7ffeccc0b739 - rustc::traits::error_reporting::<impl rustc::infer::InferCtxt<'a, 'gcx, 'tcx>>::report_selection_error::hc013179b5351d84d
   8:     0x7ffeccc00069 - rustc::traits::error_reporting::<impl rustc::infer::InferCtxt<'a, 'gcx, 'tcx>>::report_fulfillment_errors::h4433be3ed2c84ec8
   9:     0x7ffee2e425ca - <rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx> as rustc_typeck::astconv::AstConv<'gcx, 'tcx>>::record_ty::h9b01acacbcbaff91
  10:     0x7ffee2e4387a - <rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx> as rustc_typeck::astconv::AstConv<'gcx, 'tcx>>::record_ty::h9b01acacbcbaff91
  11:     0x7ffee2e43016 - <rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx> as rustc_typeck::astconv::AstConv<'gcx, 'tcx>>::record_ty::h9b01acacbcbaff91
  12:     0x7ffee2e52da9 - <rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx> as rustc_typeck::astconv::AstConv<'gcx, 'tcx>>::record_ty::h9b01acacbcbaff91
  13:     0x7ffee2e46a06 - <rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx> as rustc_typeck::astconv::AstConv<'gcx, 'tcx>>::record_ty::h9b01acacbcbaff91
  14:     0x7ffee2e5930e - <rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx> as rustc_typeck::astconv::AstConv<'gcx, 'tcx>>::record_ty::h9b01acacbcbaff91
  15:     0x7ffee2e46fb8 - <rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx> as rustc_typeck::astconv::AstConv<'gcx, 'tcx>>::record_ty::h9b01acacbcbaff91
  16:     0x7ffee2e46a06 - <rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx> as rustc_typeck::astconv::AstConv<'gcx, 'tcx>>::record_ty::h9b01acacbcbaff91
  17:     0x7ffee2e4595f - <rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx> as rustc_typeck::astconv::AstConv<'gcx, 'tcx>>::record_ty::h9b01acacbcbaff91
  18:     0x7ffee2e3678d - <rustc_typeck::check::GatherLocalsVisitor<'a, 'gcx, 'tcx> as rustc::hir::intravisit::Visitor<'gcx>>::visit_pat::hb7b0709391a3fd8d
  19:     0x7ffee2ebe159 - <rustc_typeck::outlives::test::OutlivesTest<'a, 'tcx> as rustc::hir::itemlikevisit::ItemLikeVisitor<'tcx>>::visit_item::h0e25c0a16f74e38c
  20:     0x7ffee2e76746 - <rustc_typeck::check::Diverges as core::fmt::Debug>::fmt::h1c65dfb30c7b3c51
  21:     0x7ffee2e350c2 - <rustc_typeck::check::CheckItemTypesVisitor<'a, 'tcx> as rustc::hir::itemlikevisit::ItemLikeVisitor<'tcx>>::visit_item::hf39656246afa540d
  22:     0x7ffecca7c126 - rustc::ty::maps::<impl rustc::ty::maps::queries::typeck_tables_of<'tcx>>::ensure::hba2ab45518988f23
  23:     0x7ffecd074c9a - rustc::dep_graph::graph::DepGraph::assert_ignored::h3d788a943cdbafc4
  24:     0x7ffeccb5c046 - rustc::ty::maps::<impl rustc::ty::maps::queries::instance_def_size_estimate<'tcx>>::try_get::h23404c885dbf382f
  25:     0x7ffeccd3fe27 - <rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx> as rustc::ty::layout::HasTyCtxt<'gcx>>::tcx::h93da4ee47aa7f377
  26:     0x7ffecca7c1d6 - rustc::ty::maps::<impl rustc::ty::maps::queries::typeck_tables_of<'tcx>>::ensure::hba2ab45518988f23
  27:     0x7ffecca7c9ba - rustc::ty::maps::<impl rustc::ty::maps::queries::typeck_tables_of<'tcx>>::try_get::h96e5020f96e0297c
  28:     0x7ffeccd95b6f - rustc::ty::maps::TyCtxtAt::typeck_tables_of::h4054dbb665aa1f74
  29:     0x7ffecca7c09c - rustc::ty::maps::<impl rustc::ty::maps::queries::typeck_tables_of<'tcx>>::ensure::hba2ab45518988f23
  30:     0x7ffee2f3af66 - <rustc_typeck::variance::terms::InferredIndex as core::fmt::Debug>::fmt::h774c8f2cd3b8f384
  31:     0x7ffee2e34c4d - <rustc_typeck::check::CheckItemTypesVisitor<'a, 'tcx> as rustc::hir::itemlikevisit::ItemLikeVisitor<'tcx>>::visit_item::hf39656246afa540d
  32:     0x7ffecd0936ae - rustc::dep_graph::graph::DepGraph::assert_ignored::h3d788a943cdbafc4
  33:     0x7ffeccb646b7 - rustc::ty::maps::<impl rustc::ty::maps::queries::instance_def_size_estimate<'tcx>>::try_get::h23404c885dbf382f
  34:     0x7ffeccd0ea17 - <rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx> as rustc::ty::layout::HasTyCtxt<'gcx>>::tcx::h93da4ee47aa7f377
  35:     0x7ffecca7ab8a - rustc::ty::maps::<impl rustc::ty::maps::queries::typeck_item_bodies<'tcx>>::ensure::h5a89529d361a30e7
  36:     0x7ffecca7b24f - rustc::ty::maps::<impl rustc::ty::maps::queries::typeck_item_bodies<'tcx>>::try_get::hcd0c852dadf7529b
  37:     0x7ffeccd95a57 - rustc::ty::maps::TyCtxtAt::typeck_item_bodies::h58611989c649d001
  38:     0x7ffeccd921a2 - rustc::ty::maps::<impl rustc::ty::context::TyCtxt<'a, 'tcx, 'lcx>>::typeck_item_bodies::h585d4c02703c78ad
  39:     0x7ffee2f6d5c3 - rustc_typeck::check_crate::h05100ae6a011b747
  40:     0x7ffee6cfe07d - <rustc_driver::pretty::UserIdentifiedItem as core::fmt::Debug>::fmt::hae9e730b8990bdb8
  41:     0x7ffee6d010f0 - <rustc_driver::pretty::UserIdentifiedItem as core::fmt::Debug>::fmt::hae9e730b8990bdb8
  42:     0x7ffee6d45fb0 - <rustc_driver::derive_registrar::Finder as rustc::hir::itemlikevisit::ItemLikeVisitor<'v>>::visit_item::h34e7b02473305531
  43:     0x7ffee6c80397 - rustc_driver::driver::compile_input::hc6aa0b074e7a66c3
  44:     0x7ffee6d5ee9d - rustc_driver::run_compiler::hf2ae78daa657a043
  45:     0x7ffee6c3ee2a - <unknown>
  46:     0x7ffedccbd271 - _rust_maybe_catch_panic
  47:     0x7ffee6cb490a - <rustc_driver::pretty::UserIdentifiedItem as core::fmt::Debug>::fmt::hae9e730b8990bdb8
  48:     0x7ffedccbc1cb - <<std::sys_common::remutex::ReentrantMutex<T> as core::fmt::Debug>::fmt::LockedPlaceholder as core::fmt::Debug>::fmt::h6a90c306f5c106da
  49:     0x7ffedcc8ce36 - std::sys::windows::thread::Thread::new::h62f006ffe7a96a67
  50:     0x7fff1b1a1fe3 - BaseThreadInitThunk
  51:     0x7fff1d5aefb0 - RtlUserThreadStart

error: internal compiler error: unexpected panic