[Issue 12598] New: Poor diagnostic with local import hijacking

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=12598

          Issue ID: 12598
           Summary: Poor diagnostic with local import hijacking
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Keywords: diagnostic
          Severity: enhancement
          Priority: P3
         Component: DMD
          Assignee: nobody at puremagic.com
          Reporter: thecybershadow at gmail.com

Consider the following program:

//////////////////// test.d ////////////////////
class C
{
    void addLine(string l)
    {
        debug
        {
            import std.stdio;
            stderr.writeln("Adding line: " ~ l);
        }
        lines ~= l;
    }

    immutable(string)[] lines;
}
////////////////////////////////////////////////

When compiled with -debug, the compiler produces the following error message:

test.d(10,3): Error: lines is not an lvalue

This error message is misleading - it's not clear that a symbol from std.stdio
is hijacking the "lines" field.

One way to improve the situation is to print fully-qualified symbol names in
error messages.

Another would be to add a warning or error when a locally-imported symbol is
hijacking a non-global symbol. The user can silence this message by using a
selective, static or named import.

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