<p dir="auto">On Julia 1.6 <code class="notranslate">opnorm(rand(1,0),2)</code>  and also <code class="notranslate">opnorm(rand(0,1),2)</code> fail:<br>
julia&gt; opnorm(rand(1,0),2)</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="ERROR: TypeError: in typeassert, expected Tuple, got a value of type Nothing
Stacktrace:
 [1] generic_normInf
   @ C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:465 [inlined]
 [2] normInf
   @ C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:556 [inlined]
 [3] generic_norm2(x::Matrix{Float64})
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:497
 [4] norm2(x::Matrix{Float64})
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\dense.jl:105
 [5] opnorm2
   @ C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:705 [inlined]
 [6] opnorm(A::Matrix{Float64}, p::Int64)
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:767
 [7] top-level scope
   @ REPL[44]:1
"><pre class="notranslate"><code class="notranslate">ERROR: TypeError: in typeassert, expected Tuple, got a value of type Nothing
Stacktrace:
 [1] generic_normInf
   @ C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:465 [inlined]
 [2] normInf
   @ C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:556 [inlined]
 [3] generic_norm2(x::Matrix{Float64})
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:497
 [4] norm2(x::Matrix{Float64})
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\dense.jl:105
 [5] opnorm2
   @ C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:705 [inlined]
 [6] opnorm(A::Matrix{Float64}, p::Int64)
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:767
 [7] top-level scope
   @ REPL[44]:1

</code></pre></div>
<p dir="auto">while the following work:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="julia&gt; opnorm(rand(1,0),1)
0.0

julia&gt; opnorm(rand(1,0),Inf)
0.0

julia&gt; opnorm(rand(2,0),2)
0.0

julia&gt; opnorm(rand(0,0),2)
0.0
"><pre class="notranslate"><code class="notranslate">julia&gt; opnorm(rand(1,0),1)
0.0

julia&gt; opnorm(rand(1,0),Inf)
0.0

julia&gt; opnorm(rand(2,0),2)
0.0

julia&gt; opnorm(rand(0,0),2)
0.0

</code></pre></div>
<p dir="auto">The following computation leads to an error:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="julia&gt; a = rand(1,1)
1×1 Matrix{Float64}:
 0.86747552215521

julia&gt; t = a[:,2:1]
1×0 Matrix{Float64}

julia&gt; opnorm(t)
ERROR: TypeError: in typeassert, expected Tuple, got a value of type Nothing
Stacktrace:
 [1] generic_normInf
   @ C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:465 [inlined]
 [2] normInf
   @ C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:556 [inlined]
 [3] generic_norm2(x::Matrix{Float64})
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:497
 [4] norm2(x::Matrix{Float64})
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\dense.jl:105
 [5] opnorm2
   @ C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:705 [inlined]
 [6] opnorm(A::Matrix{Float64}, p::Int64)
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:767
 [7] opnorm(A::Matrix{Float64})
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:766
 [8] top-level scope
   @ REPL[192]:1"><pre class="notranslate"><code class="notranslate">julia&gt; a = rand(1,1)
1×1 Matrix{Float64}:
 0.86747552215521

julia&gt; t = a[:,2:1]
1×0 Matrix{Float64}

julia&gt; opnorm(t)
ERROR: TypeError: in typeassert, expected Tuple, got a value of type Nothing
Stacktrace:
 [1] generic_normInf
   @ C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:465 [inlined]
 [2] normInf
   @ C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:556 [inlined]
 [3] generic_norm2(x::Matrix{Float64})
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:497
 [4] norm2(x::Matrix{Float64})
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\dense.jl:105
 [5] opnorm2
   @ C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:705 [inlined]
 [6] opnorm(A::Matrix{Float64}, p::Int64)
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:767
 [7] opnorm(A::Matrix{Float64})
   @ LinearAlgebra C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\LinearAlgebra\src\generic.jl:766
 [8] top-level scope
   @ REPL[192]:1
</code></pre></div>
<p dir="auto">But, there is no error if the matrix has a slightly different shape:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="julia&gt; a = rand(2,1);

julia&gt; t = a[:,2:1]
2×0 Matrix{Float64}

julia&gt; opnorm(t)
0.0"><pre class="notranslate"><code class="notranslate">julia&gt; a = rand(2,1);

julia&gt; t = a[:,2:1]
2×0 Matrix{Float64}

julia&gt; opnorm(t)
0.0
</code></pre></div>