<div class="highlight highlight-source-julia notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="f(x::T) where T = 1
hasmethod(f, Tuple{T} where T)"><pre class="notranslate"><span class="pl-en">f</span>(x<span class="pl-k">::</span><span class="pl-c1">T</span>) <span class="pl-k">where</span> T <span class="pl-k">=</span> <span class="pl-c1">1</span>
<span class="pl-c1">hasmethod</span>(f, Tuple{T} <span class="pl-k">where</span> T)</pre></div>
<p dir="auto">crash the julia repl on julia 1.1.1, windows 7</p>
<p dir="auto">It may be a malformed method call but it crashes julia v1.1 and only after the method has been defined:<br>
<code class="notranslate">hasmethod(Base.map!,Tuple{Any,Base.ValueIterator{D}} where D&lt;:Dict)</code></p>
<p dir="auto">While this nearly identical version does not:<br>
<code class="notranslate">hasmethod(Base.map!,Tuple{Any,Base.ValueIterator{&lt;:Dict}})</code></p>
<div class="highlight highlight-source-julia notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="Starting Julia...
               _
   _       _ _(_)_     |  Documentation: https://docs.julialang.org
  (_)     | (_) (_)    |
   _ _   _| |_  __ _   |  Type &quot;?&quot; for help, &quot;]?&quot; for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 1.1.0 (2019-01-21)
 _/ |\__'_|_|_|\__'_|  |  Official https://julialang.org/ release
|__/                   |

julia&gt; hasmethod(Base.map!,Tuple{Any,Base.ValueIterator{&lt;:Dict}})
false

julia&gt; hasmethod(Base.map!,Tuple{Any,Base.ValueIterator{D}} where D&lt;:Dict)
false

julia&gt; function Base.map!(f, iter::Base.ValueIterator{&lt;:Dict})
           dict = iter.dict
           vals = dict.vals
           # @inbounds is here so the it gets propigated to isslotfiled
           @inbounds for i = dict.idxfloor:Base.lastindex(vals)
               if Base.isslotfilled(dict, i)
                   vals[i] = f(vals[i])
               end
           end
           return iter
       end

julia&gt; hasmethod(Base.map!,Tuple{Any,Base.ValueIterator{&lt;:Dict}})
true

julia&gt; hasmethod(Base.map!,Tuple{Any,Base.ValueIterator{D}} where D&lt;:Dict)

signal (11): Segmentation fault: 11
in expression starting at no file:0
jl_compilation_sig at /Users/osx/buildbot/slave/package_osx64/build/src/gf.c:622
jl_mt_assoc_by_type at /Users/osx/buildbot/slave/package_osx64/build/src/gf.c:1139
jl_method_lookup_by_type at /Users/osx/buildbot/slave/package_osx64/build/src/gf.c:1722 [inlined]
jl_method_exists at /Users/osx/buildbot/slave/package_osx64/build/src/gf.c:1729
#hasmethod#21 at ./reflection.jl:1102 [inlined]
hasmethod at ./reflection.jl:1100
unknown function (ip: 0x11ac4ed14)
do_call at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:323
eval_stmt_value at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:362 [inlined]
eval_body at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:759
jl_interpret_toplevel_thunk_callback at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:885
unknown function (ip: 0xfffffffffffffffe)
unknown function (ip: 0x1155fe58f)
unknown function (ip: 0x6)
jl_interpret_toplevel_thunk at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:894
jl_toplevel_eval_flex at /Users/osx/buildbot/slave/package_osx64/build/src/toplevel.c:764
jl_toplevel_eval at /Users/osx/buildbot/slave/package_osx64/build/src/toplevel.c:773 [inlined]
jl_toplevel_eval_in at /Users/osx/buildbot/slave/package_osx64/build/src/toplevel.c:793
eval at ./boot.jl:328 [inlined]
repleval at /Users/nicholasdinsmore/.julia/packages/Atom/OZKl0/src/repl.jl:147
#168 at /Users/nicholasdinsmore/.julia/packages/Atom/OZKl0/src/repl.jl:182
with_logstate at ./logging.jl:395
with_logger at ./logging.jl:491 [inlined]
evalrepl at /Users/nicholasdinsmore/.julia/packages/Atom/OZKl0/src/repl.jl:173
do_call at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:323
eval_stmt_value at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:362 [inlined]
eval_body at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:759
jl_interpret_toplevel_thunk_callback at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:885
unknown function (ip: 0xfffffffffffffffe)
unknown function (ip: 0x1155fe3af)
unknown function (ip: 0xffffffffffffffff)
jl_interpret_toplevel_thunk at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:894
jl_toplevel_eval_flex at /Users/osx/buildbot/slave/package_osx64/build/src/toplevel.c:764
jl_toplevel_eval at /Users/osx/buildbot/slave/package_osx64/build/src/toplevel.c:773 [inlined]
jl_toplevel_eval_in at /Users/osx/buildbot/slave/package_osx64/build/src/toplevel.c:793
eval at ./boot.jl:328
eval_user_input at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v1.1/REPL/src/REPL.jl:85
run_backend at /Users/nicholasdinsmore/.julia/packages/Revise/RiaYX/src/Revise.jl:779
#60 at ./task.jl:259
jl_fptr_trampoline at /Users/osx/buildbot/slave/package_osx64/build/src/gf.c:1864
jl_apply at /Users/osx/buildbot/slave/package_osx64/build/src/./julia.h:1571 [inlined]
start_task at /Users/osx/buildbot/slave/package_osx64/build/src/task.c:572
Allocations: 18323023 (Pool: 18320209; Big: 2814); GC: 41

Julia has exited. Press Enter to start a new session."><pre class="notranslate">Starting Julia<span class="pl-k">...</span>
               _
   _       _ <span class="pl-c1">_</span>(_)_     <span class="pl-k">|</span>  Documentation<span class="pl-k">:</span> https<span class="pl-k">:</span><span class="pl-k">//</span>docs<span class="pl-k">.</span>julialang<span class="pl-k">.</span>org
  (_)     <span class="pl-k">|</span> (_) (_)    <span class="pl-k">|</span>
   _ _   _<span class="pl-k">|</span> <span class="pl-k">|</span>_  __ _   <span class="pl-k">|</span>  Type <span class="pl-s"><span class="pl-pds">"</span>?<span class="pl-pds">"</span></span> <span class="pl-k">for</span> help, <span class="pl-s"><span class="pl-pds">"</span>]?<span class="pl-pds">"</span></span> <span class="pl-k">for</span> Pkg help.
  <span class="pl-k">|</span> <span class="pl-k">|</span> <span class="pl-k">|</span> <span class="pl-k">|</span> <span class="pl-k">|</span> <span class="pl-k">|</span> <span class="pl-k">|</span><span class="pl-k">/</span> <span class="pl-s"><span class="pl-pds"><span class="pl-c1">_</span>`</span> |  |</span>
<span class="pl-s">  | | |_| | | | (_| |  |  Version 1.1.0 (2019-01-21)</span>
<span class="pl-s"> _/ |<span class="pl-cce">\_</span>_'_|_|_|<span class="pl-cce">\_</span>_'_|  |  Official https://julialang.org/ release</span>
<span class="pl-s">|__/                   |</span>
<span class="pl-s"></span>
<span class="pl-s">julia&gt; hasmethod(Base.map!,Tuple{Any,Base.ValueIterator{&lt;:Dict}})</span>
<span class="pl-s">false</span>
<span class="pl-s"></span>
<span class="pl-s">julia&gt; hasmethod(Base.map!,Tuple{Any,Base.ValueIterator{D}} where D&lt;:Dict)</span>
<span class="pl-s">false</span>
<span class="pl-s"></span>
<span class="pl-s">julia&gt; function Base.map!(f, iter::Base.ValueIterator{&lt;:Dict})</span>
<span class="pl-s">           dict = iter.dict</span>
<span class="pl-s">           vals = dict.vals</span>
<span class="pl-s">           # @inbounds is here so the it gets propigated to isslotfiled</span>
<span class="pl-s">           @inbounds for i = dict.idxfloor:Base.lastindex(vals)</span>
<span class="pl-s">               if Base.isslotfilled(dict, i)</span>
<span class="pl-s">                   vals[i] = f(vals[i])</span>
<span class="pl-s">               end</span>
<span class="pl-s">           end</span>
<span class="pl-s">           return iter</span>
<span class="pl-s">       end</span>
<span class="pl-s"></span>
<span class="pl-s">julia&gt; hasmethod(Base.map!,Tuple{Any,Base.ValueIterator{&lt;:Dict}})</span>
<span class="pl-s">true</span>
<span class="pl-s"></span>
<span class="pl-s">julia&gt; hasmethod(Base.map!,Tuple{Any,Base.ValueIterator{D}} where D&lt;:Dict)</span>
<span class="pl-s"></span>
<span class="pl-s">signal (11): Segmentation fault: 11</span>
<span class="pl-s">in expression starting at no file:0</span>
<span class="pl-s">jl_compilation_sig at /Users/osx/buildbot/slave/package_osx64/build/src/gf.c:622</span>
<span class="pl-s">jl_mt_assoc_by_type at /Users/osx/buildbot/slave/package_osx64/build/src/gf.c:1139</span>
<span class="pl-s">jl_method_lookup_by_type at /Users/osx/buildbot/slave/package_osx64/build/src/gf.c:1722 [inlined]</span>
<span class="pl-s">jl_method_exists at /Users/osx/buildbot/slave/package_osx64/build/src/gf.c:1729</span>
<span class="pl-s">#hasmethod#21 at ./reflection.jl:1102 [inlined]</span>
<span class="pl-s">hasmethod at ./reflection.jl:1100</span>
<span class="pl-s">unknown function (ip: 0x11ac4ed14)</span>
<span class="pl-s">do_call at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:323</span>
<span class="pl-s">eval_stmt_value at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:362 [inlined]</span>
<span class="pl-s">eval_body at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:759</span>
<span class="pl-s">jl_interpret_toplevel_thunk_callback at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:885</span>
<span class="pl-s">unknown function (ip: 0xfffffffffffffffe)</span>
<span class="pl-s">unknown function (ip: 0x1155fe58f)</span>
<span class="pl-s">unknown function (ip: 0x6)</span>
<span class="pl-s">jl_interpret_toplevel_thunk at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:894</span>
<span class="pl-s">jl_toplevel_eval_flex at /Users/osx/buildbot/slave/package_osx64/build/src/toplevel.c:764</span>
<span class="pl-s">jl_toplevel_eval at /Users/osx/buildbot/slave/package_osx64/build/src/toplevel.c:773 [inlined]</span>
<span class="pl-s">jl_toplevel_eval_in at /Users/osx/buildbot/slave/package_osx64/build/src/toplevel.c:793</span>
<span class="pl-s">eval at ./boot.jl:328 [inlined]</span>
<span class="pl-s">repleval at /Users/nicholasdinsmore/.julia/packages/Atom/OZKl0/src/repl.jl:147</span>
<span class="pl-s">#168 at /Users/nicholasdinsmore/.julia/packages/Atom/OZKl0/src/repl.jl:182</span>
<span class="pl-s">with_logstate at ./logging.jl:395</span>
<span class="pl-s">with_logger at ./logging.jl:491 [inlined]</span>
<span class="pl-s">evalrepl at /Users/nicholasdinsmore/.julia/packages/Atom/OZKl0/src/repl.jl:173</span>
<span class="pl-s">do_call at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:323</span>
<span class="pl-s">eval_stmt_value at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:362 [inlined]</span>
<span class="pl-s">eval_body at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:759</span>
<span class="pl-s">jl_interpret_toplevel_thunk_callback at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:885</span>
<span class="pl-s">unknown function (ip: 0xfffffffffffffffe)</span>
<span class="pl-s">unknown function (ip: 0x1155fe3af)</span>
<span class="pl-s">unknown function (ip: 0xffffffffffffffff)</span>
<span class="pl-s">jl_interpret_toplevel_thunk at /Users/osx/buildbot/slave/package_osx64/build/src/interpreter.c:894</span>
<span class="pl-s">jl_toplevel_eval_flex at /Users/osx/buildbot/slave/package_osx64/build/src/toplevel.c:764</span>
<span class="pl-s">jl_toplevel_eval at /Users/osx/buildbot/slave/package_osx64/build/src/toplevel.c:773 [inlined]</span>
<span class="pl-s">jl_toplevel_eval_in at /Users/osx/buildbot/slave/package_osx64/build/src/toplevel.c:793</span>
<span class="pl-s">eval at ./boot.jl:328</span>
<span class="pl-s">eval_user_input at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v1.1/REPL/src/REPL.jl:85</span>
<span class="pl-s">run_backend at /Users/nicholasdinsmore/.julia/packages/Revise/RiaYX/src/Revise.jl:779</span>
<span class="pl-s">#60 at ./task.jl:259</span>
<span class="pl-s">jl_fptr_trampoline at /Users/osx/buildbot/slave/package_osx64/build/src/gf.c:1864</span>
<span class="pl-s">jl_apply at /Users/osx/buildbot/slave/package_osx64/build/src/./julia.h:1571 [inlined]</span>
<span class="pl-s">start_task at /Users/osx/buildbot/slave/package_osx64/build/src/task.c:572</span>
<span class="pl-s">Allocations: 18323023 (Pool: 18320209; Big: 2814); GC: 41</span>
<span class="pl-s"></span>
<span class="pl-s">Julia has exited. Press Enter to start a new session.</span></pre></div>