Freezing after calling strcat()

str1 = ["John ","Mary "];
str2 = ["Smith","Jones"];
str = strcat(str1,str2)

The code above is the example code from https://ww2.mathworks.cn/help/matlab/ref/strcat.html

Running this code will cause freezing, as if strcat actually doesn't support strings.

[Stephen23]

@Disciple of the Forbidden Spell: what MATLAB version are you using? Please show the output of this command:

which strcat -all

[Walter Roberson]

Just to check: what shows up for

which strcat(str1,str2)

[Disciple of the Forbidden Spell]

>> which strcat -all

C:\Program Files\Polyspace\R2019a\toolbox\matlab\strfun\strcat.p

C:\Program Files\Polyspace\R2019a\toolbox\matlab\strfun\@cell\strcat.p % cell method

C:\Program Files\Polyspace\R2019a\toolbox\matlab\strfun\@cell\strcat.m % cell method

C:\Program Files\Polyspace\R2019a\toolbox\matlab\strfun\@string\strcat.m % string method

C:\Program Files\Polyspace\R2019a\toolbox\matlab\strfun\strcat.m % Shadowed

>> which strcat(str1,str2)

C:\Program Files\Polyspace\R2019a\toolbox\matlab\strfun\@string\strcat.m % string method

[Walter Roberson]

str = str1 + str2;

[Disciple of the Forbidden Spell]

@Walter Roberson

That works. But what's wrong with strcat?

[Walter Roberson]

I do not know. Perhaps it is related to Polyspace, but I do not know.