ICE: assertion failed: bpos.to_u32() >= mbc.pos.to_u32() + mbc.bytes as u32

[L3afMe]

Code

I tried finding a minified way to reproduce the error but couldn't manage to do it, here's where it occurs:
https://github.com/L3afMe/colou-rs/blob/master/src/main.rs#L117-L152

Meta

rustc --version --verbose:

rustc 1.52.0-nightly (107896c32 2021-03-15)
binary: rustc
commit-hash: 107896c32d5dda4db508968ff34997a39d286966
commit-date: 2021-03-15
host: x86_64-unknown-linux-gnu
release: 1.52.0-nightly
LLVM version: 12.0.0

Error output

thread 'rustc' panicked at 'assertion failed: bpos.to_u32() >= mbc.pos.to_u32() + mbc.bytes as u32', compiler/rustc_span/src/lib.rs:1513:17

Backtrace

   0: rust_begin_unwind
             at /rustc/107896c32d5dda4db508968ff34997a39d286966/library/std/src/panicking.rs:493:5
   1: core::panicking::panic_fmt
             at /rustc/107896c32d5dda4db508968ff34997a39d286966/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/107896c32d5dda4db508968ff34997a39d286966/library/core/src/panicking.rs:50:5
   3: rustc_span::SourceFile::lookup_file_pos
   4: rustc_span::SourceFile::lookup_file_pos_with_col_display
   5: rustc_span::source_map::SourceMap::lookup_char_pos
   6: rustc_errors::emitter::EmitterWriter::get_multispan_max_line_num
   7: <rustc_errors::emitter::EmitterWriter as rustc_errors::emitter::Emitter>::emit_diagnostic
   8: rustc_errors::json::Diagnostic::from_errors_diagnostic
   9: <rustc_errors::json::JsonEmitter as rustc_errors::emitter::Emitter>::emit_diagnostic
  10: rustc_errors::HandlerInner::emit_diagnostic
  11: rustc_errors::diagnostic_builder::DiagnosticBuilder::emit
  12: rustc_builtin_macros::format::expand_preparsed_format_args
  13: rustc_builtin_macros::format::expand_format_args_impl
  14: rustc_expand::expand::MacroExpander::fully_expand_fragment
  15: rustc_expand::expand::MacroExpander::expand_crate
  16: rustc_session::utils::<impl rustc_session::session::Session>::time
  17: rustc_interface::passes::configure_and_expand_inner
  18: rustc_interface::passes::configure_and_expand::{{closure}}
  19: rustc_data_structures::box_region::PinnedGenerator<I,A,R>::new
  20: rustc_interface::passes::configure_and_expand
  21: rustc_interface::queries::Queries::expansion
  22: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  23: rustc_span::with_source_map
  24: scoped_tls::ScopedKey<T>::set

[osa1]

Smaller repro:

fn main() {
    println!(
        "\
            \n {} │",
    );
}

[osa1]

@rustbot claim

PR coming.

[osa1]

This revealed another bug (#83344). When both are fixed the error message is now:

   Compiling colou-rs v0.1.0 (/home/omer/rust/issue83340/colou-rs)
error: 27 positional arguments in format string, but there are 26 arguments
   --> src/main.rs:118:16
    |
118 |             "  {}\
    |                ^^
119 |             \n ╭───────────╮ ╭───────────╮\
120 |             \n │   {}   │ │  {} │\
    |                    ^^        ^^
121 |             \n │  {}  │ │  {}  │\
    |                   ^^       ^^
122 |             \n │  {}  │ │  {}  │\
    |                   ^^       ^^
123 |             \n │  {}  │ │  {}  │\
    |                   ^^       ^^
124 |             \n ╰───────────╯ │  {}  │\
    |                                 ^^
125 |             \n ╭───────────╮ ╰───────────╯\
126 |             \n │ {} │ ╭───────────╮\
    |                  ^^
127 |             \n │  {}  │ │   {}  │\
    |                   ^^        ^^
128 |             \n │  {}  │ │  {}  │\
    |                   ^^       ^^
129 |             \n │  {}  │ │  {}  │\
    |                   ^^       ^^
130 |             \n ╰───────────╯ │  {}  │\
    |                                 ^^
131 |             \n ╭───────────╮ │  {}  │\
    |                                 ^^
132 |             \n │   {}   │ │  {}  │\
    |                    ^^        ^^
133 |             \n │  {}  │ │  {}  │\
    |                   ^^       ^^
134 |             \n │  {}  │ │  {}  │\
    |                   ^^       ^^
135 |             \n │  {}  │ │  {}  │\
    |                   ^^       ^^
136 |             \n ╰───────────╯ ╰───────────╯",
137 |             ulb.paint(format!("Complementary color for {}", color.to_hex())),
    |             ----------------------------------------------------------------
138 |             ul.paint("Triad"),     ul.paint("Tetradic"),
    |             -----------------      --------------------
139 |             triad[0].paint_hex(),  tetradic[0].paint_hex(),
    |             --------------------   -----------------------
140 |             triad[1].paint_hex(),  tetradic[1].paint_hex(),
    |             --------------------   -----------------------
141 |             triad[2].paint_hex(),  tetradic[2].paint_hex(),
    |             --------------------   -----------------------
142 |                                    tetradic[3].paint_hex(),
    |                                    -----------------------
143 |             ul.paint("Analogous"), 
    |             ---------------------
144 |             anal[0].paint_hex(),   ul.paint("Shades"),
    |             -------------------    ------------------
145 |             anal[1].paint_hex(),   anal[0].paint_hex(),
    |             -------------------    -------------------
146 |             anal[2].paint_hex(),   anal[0].paint_hex(),
    |             -------------------    -------------------
147 |                                    anal[0].paint_hex(),
    |                                    -------------------
148 |             ul.paint("Split"),     anal[0].paint_hex(),
    |             -----------------      -------------------
149 |             s_comp[0].paint_hex(), anal[0].paint_hex(),
    |             ---------------------  -------------------
150 |             s_comp[1].paint_hex(), anal[0].paint_hex(),
    |             ---------------------  -------------------
151 |             s_comp[2].paint_hex(), anal[0].paint_hex(),
    |             ---------------------  -------------------

warning: unused import: `hsv::HSVColor`
 --> src/colors/rgb.rs:1:53
  |
1 | use crate::colors::{ansi::ColorAnsi, hsl::HSLColor, hsv::HSVColor, ColorComponent, ColorComponentConvert, Error};
  |                                                     ^^^^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

error: aborting due to previous error; 1 warning emitted

error: could not compile `colou-rs`

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