Enum VariableType 

enum VariableType<'db> {
    Ast(VariableDecl<'db>),
    InProgress(VariableDecl<'db>),
    Symbolic(SymTy<'db>),
}

The type of a variable.

Variants

Ast(VariableDecl<'db>)

AST form of the type is available and we have not yet begun to symbolify it. AST types are used when we introduce a set of variables, where each variable may refer to others as part of its type. In that case we don’t know the right order to process the variables in so we have to do a depth-first search.

e.g., in fn foo(x: shared[y] String, y: my Vec[String]), we could begin with y then x, but that is not clear at first. So instead we begin with x, mark it as in progress, and then to convert y to a symbolic expression, wind up converting the type of y. If y did refer to x, this would result in an error.

InProgress(VariableDecl<'db>)

AST form of the type is available and we have begun symbolifying it. When in this state, a repeated request for the variable’s type will report an error.

Symbolic(SymTy<'db>)

Symbolic type is available. For local variables, we introduce the type directly in this form, but for parameters or other cases where there are a set of variables introduced at once, we have to begin with AST form.

Trait Implementations

impl<'db> Clone for VariableType<'db>

fn clone(&self) -> VariableType<'db>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'db> Copy for VariableType<'db>