roc/compiler/mono/tests/helpers/mod.rs

extern crate bumpalo;

use self::bumpalo::Bump;
use roc_can::constraint::Constraint;
use roc_can::env::Env;
use roc_can::expected::Expected;
use roc_can::expr::{canonicalize_expr, Expr, Output};
use roc_can::operator;
use roc_can::scope::Scope;
use roc_collections::all::{ImMap, MutMap, SendMap};
use roc_constrain::expr::constrain_expr;
use roc_constrain::module::{constrain_imported_values, load_builtin_aliases, Import};
use roc_module::symbol::{IdentIds, Interns, ModuleId, ModuleIds};
use roc_parse::ast::{self, Attempting};
use roc_parse::blankspace::space0_before;
use roc_parse::parser::{loc, Fail, Parser, State};
use roc_problem::can::Problem;
use roc_region::all::{Located, Region};
use roc_solve::solve;
use roc_types::subs::{Content, Subs, VarStore, Variable};
use roc_types::types::Type;

pub fn test_home() -> ModuleId {
    ModuleIds::default().get_or_insert(&"Test".into())
}

pub fn infer_expr(
    subs: Subs,
    problems: &mut Vec<roc_solve::solve::TypeError>,
    constraint: &Constraint,
    expr_var: Variable,
) -> (Content, Subs) {
    let env = solve::Env {
        aliases: MutMap::default(),
        vars_by_symbol: SendMap::default(),
    };
    let (solved, _) = solve::run(&env, problems, subs, constraint);

    let content = solved.inner().get_without_compacting(expr_var).content;

    (content, solved.into_inner())
}

pub fn parse_loc_with<'a>(arena: &'a Bump, input: &'a str) -> Result<Located<ast::Expr<'a>>, Fail> {
    let state = State::new(&input, Attempting::Module);
    let parser = space0_before(loc(roc_parse::expr::expr(0)), 0);
    let answer = parser.parse(&arena, state);

    answer
        .map(|(loc_expr, _)| loc_expr)
        .map_err(|(fail, _)| fail)
}

pub fn can_expr(expr_str: &str) -> CanExprOut {
    can_expr_with(&Bump::new(), test_home(), expr_str)
}

pub struct CanExprOut {
    pub loc_expr: Located<Expr>,
    pub output: Output,
    pub problems: Vec<Problem>,
    pub home: ModuleId,
    pub interns: Interns,
    pub var_store: VarStore,
    pub var: Variable,
    pub constraint: Constraint,
}

pub fn can_expr_with(arena: &Bump, home: ModuleId, expr_str: &str) -> CanExprOut {
    let loc_expr = parse_loc_with(&arena, expr_str).unwrap_or_else(|e| {
        panic!(
            "can_expr_with() got a parse error when attempting to canonicalize:\n\n{:?} {:?}",
            expr_str, e
        )
    });

    let mut var_store = VarStore::default();
    let var = var_store.fresh();
    let expected = Expected::NoExpectation(Type::Variable(var));
    let module_ids = ModuleIds::default();

    // Desugar operators (convert them to Apply calls, taking into account
    // operator precedence and associativity rules), before doing other canonicalization.
    //
    // If we did this *during* canonicalization, then each time we
    // visited a BinOp node we'd recursively try to apply this to each of its nested
    // operators, and then again on *their* nested operators, ultimately applying the
    // rules multiple times unnecessarily.
    let loc_expr = operator::desugar_expr(arena, &loc_expr);

    let mut scope = Scope::new(home);
    let dep_idents = IdentIds::exposed_builtins(0);
    let mut env = Env::new(home, dep_idents, &module_ids, IdentIds::default());
    let (loc_expr, output) = canonicalize_expr(
        &mut env,
        &mut var_store,
        &mut scope,
        Region::zero(),
        &loc_expr.value,
    );

    // Add the builtins' defs.
    let mut with_builtins = loc_expr.value;

    // Add builtin defs (e.g. List.get) directly to the canonical Expr,
    // since we aren't using modules here.
    let builtin_defs = roc_can::builtins::builtin_defs(&mut var_store);

    for (symbol, def) in builtin_defs {
        if output.references.lookups.contains(&symbol) || output.references.calls.contains(&symbol)
        {
            with_builtins = roc_can::expr::Expr::LetNonRec(
                Box::new(def),
                Box::new(Located {
                    region: Region::zero(),
                    value: with_builtins,
                }),
                var_store.fresh(),
                SendMap::default(),
            );
        }
    }

    let loc_expr = Located {
        region: loc_expr.region,
        value: with_builtins,
    };

    let constraint = constrain_expr(
        &roc_constrain::expr::Env {
            rigids: ImMap::default(),
            home,
        },
        loc_expr.region,
        &loc_expr.value,
        expected,
    );

    let types = roc_builtins::std::types();

    let imports: Vec<_> = types
        .into_iter()
        .map(|(symbol, (solved_type, region))| Import {
            loc_symbol: Located::at(region, symbol),
            solved_type,
        })
        .collect();

    //load builtin values
    let (_introduced_rigids, constraint) =
        constrain_imported_values(imports, constraint, &mut var_store);

    //load builtin types
    let mut constraint =
        load_builtin_aliases(roc_builtins::std::aliases(), constraint, &mut var_store);

    constraint.instantiate_aliases(&mut var_store);

    let mut all_ident_ids = MutMap::default();

    // When pretty printing types, we may need the exposed builtins,
    // so include them in the Interns we'll ultimately return.
    for (module_id, ident_ids) in IdentIds::exposed_builtins(0) {
        all_ident_ids.insert(module_id, ident_ids);
    }

    all_ident_ids.insert(home, env.ident_ids);

    let interns = Interns {
        module_ids: env.module_ids.clone(),
        all_ident_ids,
    };

    CanExprOut {
        loc_expr,
        output,
        problems: env.problems,
        home: env.home,
        var_store,
        interns,
        var,
        constraint,
    }
}

#[derive(Default)]
pub struct SeenVariables {
    pub rigid_vars: Vec<Variable>,
    pub flex_vars: Vec<Variable>,
}