https://issues.dlang.org/show_bug.cgi?id=24738

          Issue ID: 24738
           Summary: Import core.interpolation suggestion
           Product: D
           Version: D2
          Hardware: x86
                OS: Windows
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: msnmancini@hotmail.com

When identifying errors such as

```
onlineapp.d(4): Error: undefined identifier InterpolationHeader
onlineapp.d(47): Error: template heresy is not callable using argument types
!()(InterpolationHeader,
InterpolatedLiteral!"http://localhost:8000/users/userid=",
InterpolatedExpression!"i", int, InterpolationFooter)
onlineapp.d(4):        Candidate is: heresy(Args...)(InterpolationHeader
header, Args args, InterpolationFooter footer)
```


InterpolationHeader, InterpolationFooter, the compiler could suggest the import as it can be tricky for someone starting to use the interpolation feature.

--