Bug 19720 – const structs without explicit initializer are not usable in CTFE expressions

Code: dmd -main -run -<<<'struct S {int i;}const S s;pragma(msg, s);' Expected output: S(0) Actual output: __stdin.d(1): Error: static variable s cannot be read at compile time __stdin.d(1): while evaluating pragma(msg, s) Note that initializing explicitly using a struct initializer literal gives the expected result: dmd -main -run -<<<'struct S {int i;}const S s={};pragma(msg, s);' S(0)

This is intended behavior - a const variable with an initializer has a known value at compile time, while one without is expected to be initialized in a static constructor, and using its value before that point is undefined behavior.