No short-circuit evaluation in static context (ex. when)

[dawkot]

Because compiles((let _ = (echo "")) is false, compiler probably shouldn't try to compile (echo "") is int.

Example

template foo(x) =
  when compiles((let _ = x)) and x is int:
    discard

foo:
  echo ""

Current Output

Error: expression 'echo [""]' has no type (or is ambiguous)

Additional Information

Nim 1.2.0 and current devel 6aa971d

[timotheecour]

see #13541 + whole discussion around it

[jibal]

It doesn't and shouldn't work that way. compiles((let _ = x)) and x is int is an expression and must be well formed.
Use when (when compiles((let _ = x)): x is int else: false):