Add type information to the nodes of an elm-syntax tree.

import Elm.Syntax.Node
import Elm.Syntax.Expression
import ElmSyntaxTypeInfer


[ { declaration =
        Elm.Syntax.Node.empty
            { expression =
                Elm.Syntax.Node.empty
                    (Elm.Syntax.Expression.ListExpr
                        [ Elm.Syntax.Node.empty
                            (Elm.Syntax.Expression.Integer 1)
                        ]
                    )
            , name = Elm.Syntax.Node.empty "majorVersions"
            , arguments = []
            }
  , signature = Nothing
  , documentation = Nothing
  }
]
    |> ElmSyntaxTypeInfer.valueOrFunctionDeclarations
        { importedTypes = ElmSyntaxTypeInfer.elmCoreTypes
        , moduleOriginLookup = exampleModuleOriginLookup
        , otherModuleDeclaredTypes =
            []
                |> ElmSyntaxTypeInfer.moduleDeclarationsToTypes
                    exampleModuleOriginLookup
                |> .types
        }
    |> Result.map (List.map .type_)
-->
Ok
    [ ElmSyntaxTypeInfer.TypeNotVariable
        (ElmSyntaxTypeInfer.TypeConstruct
            { moduleOrigin = [ "List" ]
            , name = "List"
            , arguments =
                [ ElmSyntaxTypeInfer.TypeVariable "number" ]
            }
        )
    ]


exampleModuleOriginLookup : ElmSyntaxTypeInfer.ModuleOriginLookup
exampleModuleOriginLookup =
    []
        |> ElmSyntaxTypeInfer.importsToModuleOriginLookup
            ElmSyntaxTypeInfer.elmCoreTypes

TODO

• add more tests, especially let-in
• implement multi-expression-declarations type infer
• (mutually) recursive type aliases can run into an infinite loop
• type infer record type alias constructor function reference expression. Requires storing Maybe (List String) field order in module type alias declaration types
• optimize equivalentVariablesMergeWithSetOf2, potentially de-optimize typedNodeReplaceTypeBy

performance problems?

Right now, this can't handle medium to large files at an acceptable speed.