Bug 1986 – Mixin code from website doesn't compile

This example from http://www.digitalmars.com/d/2.0/mixin.html doesn’t compile: template GenStruct(char[] Name, char[] M1) { const char[] GenStruct = "struct " ~ Name ~ "{ int " ~ M1 ~ "; }"; } mixin(GenStruct!("Foo", "bar"));

The corrected template doesn't compile, it looks like string /invariant(char)[]/ prevents compilation, changing the type to 'invariant char[]' and everything is ok. Also the error message doesn't have a line number, so there is probably two bugs occuring. main.d ------ template GenStruct(string Name, string M1) { string GenStruct = "struct " ~ Name ~ "{ int " ~ M1 ~ "; }"; } mixin(GenStruct!("Foo", "bar")); C:\>dmd main.d attribute argument to mixin must be a string, not (GenStruct)

This is working in DMD v2.020. The line number is in error message, but the message is still confusing because GenStruct *is* declared as a string, it should be declared as an 'invariant char [] GenStruct = ...'. main.d ------ template GenStruct(string Name, string M1) { string GenStruct = "struct " ~ Name ~ "{ int " ~ M1 ~ "; }"; } mixin(GenStruct!("Foo", "bar")); main.d(5): Error: argument to mixin must be a string, not (GenStruct)

Added keyword diagnostic and simplified example, should error message should say "test.d(5): Error: argument to mixin must be a *invariant char[]* not (*invariant(char)[]*)"? test.d ------ invariant char[] str1 = "int x1;"; // OK mixin(str1); // OK string str2 = "int x2;"; mixin(str2); // Fails, test.d(5): Error: argument to mixin must be a string, not (str2)

*** Issue 6388 has been marked as a duplicate of this issue. ***

> main.d(5): Error: argument to mixin must be a string, not (GenStruct) is now: > Error: variable GenStruct cannot be read at compile time and > Error: argument to mixin must be a string, not (str2) is: > Error: variable str2 cannot be read at compile time