Bug 2026 – Misleading error message when passing non-existent symbol to template

Prompted by a post by Bryan Myers: import std.string; import std.algorithm; void main(char[][] args) { string[] words = ["c", "ab", "bb"]; sort!("a < b", SortStrategy.stable)(words); assert(words == ["ab", "bb", "c"]); } The code uses the non-existent symbol SortStrategy.stable instead of the correct SwapStrategy.stable. However, the error message implies that the symbol does exist and has type int: /home/andrei/test.d(8): template std.algorithm.sort(alias less,SwapStrategy ss = SwapStrategy.unstable,alias iterSwap = .iterSwap,Range) does not match any function template declaration /home/andrei/test.d(8): template std.algorithm.sort(alias less,SwapStrategy ss = SwapStrategy.unstable,alias iterSwap = .iterSwap,Range) cannot deduce template function from argument types !("a < b",int)(invariant(char)[][])

This looks like a case of an old issue (which ought to be reported, but I can't seem to find it) where any expression found invalid by semantic analysis is treated as int, except that this kind of error normally follows an error explaining that the expression is invalid.

The test case now prints: testx.d(7): Error: undefined identifier SortStrategy.stable testx.d(7): Error: template std.algorithm.sort(alias less = "a < b",SwapStrategy ss = SwapStrategy.unstable,Range) does not match any function template declarat ion testx.d(7): Error: template std.algorithm.sort(alias less = "a < b",SwapStrategy ss = SwapStrategy.unstable,Range) cannot deduce template function from argument types !("a < b",_error_)(string[]) testx.d(7): Error: template instance errors instantiating template (dmd 2.053) Which correctly identifies the cause of the error.