stage2: Sema cannot distinguish vectors from arrays in expressions

[sengir]

Zig Version

0.10.0-dev.1463+5d943f621

Steps to Reproduce

An explicitly typed array initializer within an expression:

_ = -@Vector(4, i32){ 1, 2, 3, 4 };

Note that this still occurs with aliased types:

const i32x4 = std.meta.Vector(4, i32);
_ = i32x4{ 1, 2, 3, 4 } + i32x4{ 1, 2, 3, 4 };

Expected Behavior

Sema to receive type information to identify this array_init as a vector_type so the negation operator can be performed (as arrays cannot be negated, but vectors can).

Actual Behavior

Sema receives an array_init ZIR instruction pointing to each member of the initializer, but the instruction does not point to the explicitly provided vector_type, making Sema unable to determine if this list is allowed to negated. Instead, Sema will always infer that array_init returns an array, which cannot be negated.

The current workaround is to move these initializers into intermediate variables to force them to get coerced into vectors before being used.

[topolarity]

Note to future implementer: I believe #11182 is related - tuples run into the same problem