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Merge pull request #2054 from rtfeldman/i/1804-inference-var
Implement type checking in the presence of `_` inference variables
This commit is contained in:
Richard Feldman
GitHub
commit
22adbe0bce
5 changed files with 335 additions and 2 deletions
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@ -2492,4 +2492,121 @@ pub mod test_constrain {
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"custom",
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);
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}
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#[test]
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fn inference_var_inside_arrow() {
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infer_eq(
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indoc!(
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r#"
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id : _ -> _
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id = \x -> x
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id
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"#
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),
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"a -> a",
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)
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}
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#[test]
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#[ignore = "TODO: Type2::substitute"]
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fn inference_var_inside_ctor() {
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infer_eq(
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indoc!(
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r#"
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canIGo : _ -> Result _ _
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canIGo = \color ->
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when color is
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"green" -> Ok "go!"
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"yellow" -> Err (SlowIt "whoa, let's slow down!")
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"red" -> Err (StopIt "absolutely not")
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_ -> Err (UnknownColor "this is a weird stoplight")
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canIGo
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"#
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),
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"Str -> Result Str [ SlowIt Str, StopIt Str, UnknownColor Str ]*",
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)
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}
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#[test]
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#[ignore = "TODO: Gives { x : *, y : * } -> { x : *, y : * }. This is a bug in typechecking defs with annotations."]
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fn inference_var_inside_ctor_linked() {
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infer_eq(
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indoc!(
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r#"
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swapRcd: {x: _, y: _} -> {x: _, y: _}
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swapRcd = \{x, y} -> {x: y, y: x}
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swapRcd
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"#
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),
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"{ x : a, y : b } -> { x : b, y : a }",
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)
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}
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#[test]
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fn inference_var_link_with_rigid() {
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infer_eq(
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indoc!(
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r#"
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swapRcd: {x: tx, y: ty} -> {x: _, y: _}
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swapRcd = \{x, y} -> {x: y, y: x}
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swapRcd
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"#
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),
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"{ x : tx, y : ty } -> { x : ty, y : tx }",
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)
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}
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#[test]
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#[ignore = "TODO: Type2::substitute"]
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fn inference_var_inside_tag_ctor() {
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infer_eq(
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indoc!(
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r#"
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badComics: Bool -> [ CowTools _, Thagomizer _ ]
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badComics = \c ->
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when c is
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True -> CowTools "The Far Side"
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False -> Thagomizer "The Far Side"
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badComics
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"#
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),
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"Bool -> [ CowTools Str, Thagomizer Str ]",
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)
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}
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#[test]
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fn inference_var_tag_union_ext() {
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// TODO: we should really be inferring [ Blue, Orange ]a -> [ Lavender, Peach ]a here.
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// See https://github.com/rtfeldman/roc/issues/2053
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infer_eq(
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indoc!(
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r#"
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pastelize: _ -> [ Lavender, Peach ]_
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pastelize = \color ->
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when color is
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Blue -> Lavender
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Orange -> Peach
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col -> col
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pastelize
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"#
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),
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"[ Blue, Lavender, Orange, Peach ]a -> [ Blue, Lavender, Orange, Peach ]a",
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)
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}
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#[test]
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#[ignore = "TODO: gives { email : a, name : b }c -> { email : a, name : b }c. This is a bug in typechecking defs with annotations."]
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fn inference_var_rcd_union_ext() {
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infer_eq(
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indoc!(
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r#"
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setRocEmail : _ -> { name: Str, email: Str }_
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setRocEmail = \person ->
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{ person & email: "\(person.name)@roclang.com" }
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setRocEmail
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"#
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),
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"{ email : Str, name : Str }a -> { email : Str, name : Str }a",
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)
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}
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}
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@ -390,7 +390,9 @@ pub fn to_type2<'a>(
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}
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}
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Inferred => {
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unimplemented!();
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let var = env.var_store.fresh();
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Type2::Variable(var)
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}
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Wildcard | Malformed(_) => {
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let var = env.var_store.fresh();
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@ -460,7 +460,10 @@ fn can_annotation_help(
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Type::Variable(var)
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}
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Inferred => {
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unimplemented!();
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// Inference variables aren't bound to a rigid or a wildcard, so all we have to do is
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// make a fresh unconstrained variable, and let the type solver fill it in for us 🤠
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let var = var_store.fresh();
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Type::Variable(var)
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}
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Malformed(string) => {
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malformed(env, region, string);
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@ -4604,4 +4604,117 @@ mod solve_expr {
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"RBTree {}",
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);
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}
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#[test]
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fn inference_var_inside_arrow() {
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infer_eq_without_problem(
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indoc!(
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r#"
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id : _ -> _
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id = \x -> x
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id
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"#
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),
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"a -> a",
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)
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}
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#[test]
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fn inference_var_inside_ctor() {
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infer_eq_without_problem(
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indoc!(
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r#"
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canIGo : _ -> Result _ _
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canIGo = \color ->
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when color is
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"green" -> Ok "go!"
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"yellow" -> Err (SlowIt "whoa, let's slow down!")
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"red" -> Err (StopIt "absolutely not")
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_ -> Err (UnknownColor "this is a weird stoplight")
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canIGo
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"#
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),
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"Str -> Result Str [ SlowIt Str, StopIt Str, UnknownColor Str ]*",
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)
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}
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#[test]
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fn inference_var_inside_ctor_linked() {
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infer_eq_without_problem(
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indoc!(
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r#"
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swapRcd: {x: _, y: _} -> {x: _, y: _}
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swapRcd = \{x, y} -> {x: y, y: x}
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swapRcd
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"#
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),
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"{ x : a, y : b } -> { x : b, y : a }",
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)
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}
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#[test]
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fn inference_var_link_with_rigid() {
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infer_eq_without_problem(
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indoc!(
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r#"
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swapRcd: {x: tx, y: ty} -> {x: _, y: _}
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swapRcd = \{x, y} -> {x: y, y: x}
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swapRcd
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"#
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),
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"{ x : tx, y : ty } -> { x : ty, y : tx }",
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)
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}
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#[test]
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fn inference_var_inside_tag_ctor() {
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infer_eq_without_problem(
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indoc!(
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r#"
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badComics: Bool -> [ CowTools _, Thagomizer _ ]
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badComics = \c ->
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when c is
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True -> CowTools "The Far Side"
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False -> Thagomizer "The Far Side"
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badComics
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"#
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),
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"Bool -> [ CowTools Str, Thagomizer Str ]",
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)
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}
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#[test]
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fn inference_var_tag_union_ext() {
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// TODO: we should really be inferring [ Blue, Orange ]a -> [ Lavender, Peach ]a here.
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// See https://github.com/rtfeldman/roc/issues/2053
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infer_eq_without_problem(
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indoc!(
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r#"
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pastelize: _ -> [ Lavender, Peach ]_
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pastelize = \color ->
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when color is
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Blue -> Lavender
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Orange -> Peach
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col -> col
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pastelize
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"#
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),
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"[ Blue, Lavender, Orange, Peach ]a -> [ Blue, Lavender, Orange, Peach ]a",
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)
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}
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#[test]
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fn inference_var_rcd_union_ext() {
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infer_eq_without_problem(
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indoc!(
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r#"
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setRocEmail : _ -> { name: Str, email: Str }_
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setRocEmail = \person ->
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{ person & email: "\(person.name)@roclang.com" }
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setRocEmail
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"#
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),
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"{ email : Str, name : Str }a -> { email : Str, name : Str }a",
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)
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}
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}
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@ -6667,4 +6667,102 @@ I need all branches in an `if` to have the same type!
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),
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)
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}
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#[test]
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fn inference_var_not_enough_in_alias() {
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report_problem_as(
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indoc!(
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r#"
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canIGo : _ -> Result _
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canIGo = \color ->
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when color is
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"green" -> Ok "go!"
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"yellow" -> Err (SlowIt "whoa, let's slow down!")
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"red" -> Err (StopIt "absolutely not")
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_ -> Err (UnknownColor "this is a weird stoplight")
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canIGo
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"#
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),
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indoc!(
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r#"
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── TOO FEW TYPE ARGUMENTS ──────────────────────────────────────────────────────
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The `Result` alias expects 2 type arguments, but it got 1 instead:
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1│ canIGo : _ -> Result _
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^^^^^^^^
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Are there missing parentheses?
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"#
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),
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)
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}
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#[test]
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fn inference_var_too_many_in_alias() {
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report_problem_as(
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indoc!(
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r#"
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canIGo : _ -> Result _ _ _
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canIGo = \color ->
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when color is
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"green" -> Ok "go!"
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"yellow" -> Err (SlowIt "whoa, let's slow down!")
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"red" -> Err (StopIt "absolutely not")
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_ -> Err (UnknownColor "this is a weird stoplight")
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canIGo
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"#
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),
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indoc!(
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r#"
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── TOO MANY TYPE ARGUMENTS ─────────────────────────────────────────────────────
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The `Result` alias expects 2 type arguments, but it got 3 instead:
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1│ canIGo : _ -> Result _ _ _
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^^^^^^^^^^^^
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Are there missing parentheses?
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"#
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),
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)
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}
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#[test]
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fn inference_var_conflict_in_rigid_links() {
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report_problem_as(
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indoc!(
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r#"
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f : a -> (_ -> b)
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f = \x -> \y -> if x == y then x else y
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f
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"#
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),
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// TODO: We should tell the user that we inferred `_` as `a`
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indoc!(
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r#"
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── TYPE MISMATCH ───────────────────────────────────────────────────────────────
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Something is off with the body of the `f` definition:
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1│ f : a -> (_ -> b)
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2│ f = \x -> \y -> if x == y then x else y
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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The body is an anonymous function of type:
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a -> a
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But the type annotation on `f` says it should be:
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a -> b
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Tip: Your type annotation uses `a` and `b` as separate type variables.
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Your code seems to be saying they are the same though. Maybe they
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should be the same your type annotation? Maybe your code uses them in
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a weird way?
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"#
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),
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)
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}
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}
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