https://bugs.llvm.org/show_bug.cgi?id=49194
Bug ID: 49194
Summary: unordered_map accepts non const hasher functor
Product: clang
Version: trunk
Hardware: Macintosh
OS: MacOS X
Status: NEW
Severity: normal
Priority: P
Component: C++11
Assignee: [email protected]
Reporter: [email protected]
CC: [email protected], [email protected],
[email protected], [email protected],
[email protected]
If I want to create a unordered_map with a custom hasher, I need to provide a
functor that accepts the Key as a 3rd template parameter.
On all other compilers functors operator() should accept a Key as a const
parameter, if it is not const code will not compile.
clang ignores this error.
INVALID CODE THAT SHOULD NOT COMPILED(allowing hasher to change Key object):
```
struct pizza_hasher
{
size_t operator()(std::set<std::string> &s) const
{
std::hash<std::string> string_hasher;
size_t res = 23;
for(const string &str : s)
res ^= string_hasher(str);
return res;
}
};
using Pizzas = std::unordered_map<std::set<std::string>, std::vector<int>,
pizza_hasher>;
```
reproduced on:
Apple clang version 12.0.0 (clang-1200.0.32.29)
EXPECTED RESULT:
compilation error
ACTUAL RESULT:
compilation OK
valid code as a reference:
```
struct pizza_hasher
{
size_t operator()(const std::set<std::string> &s) const
{
std::hash<std::string> string_hasher;
size_t res = 23;
for(const string &str : s)
res ^= string_hasher(str);
return res;
}
};
using Pizzas = std::unordered_map<std::set<std::string>, std::vector<int>,
pizza_hasher>;
```
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