Move solve problems to their own crate

crates/compiler/solve_problem/src/lib.rs

@@ -0,0 +1,61 @@
+use roc_can::expected::{Expected, PExpected};
+use roc_module::symbol::Symbol;
+use roc_problem::can::CycleEntry;
+use roc_region::all::Region;
+
+use roc_types::types::{Category, ErrorType, PatternCategory};
+
+#[derive(Debug, Clone)]
+pub enum TypeError {
+    BadExpr(Region, Category, ErrorType, Expected<ErrorType>),
+    BadPattern(Region, PatternCategory, ErrorType, PExpected<ErrorType>),
+    CircularType(Region, Symbol, ErrorType),
+    CircularDef(Vec<CycleEntry>),
+    BadType(roc_types::types::Problem),
+    UnexposedLookup(Symbol),
+    UnfulfilledAbility(Unfulfilled),
+    BadExprMissingAbility(Region, Category, ErrorType, Vec<Unfulfilled>),
+    BadPatternMissingAbility(Region, PatternCategory, ErrorType, Vec<Unfulfilled>),
+    Exhaustive(roc_exhaustive::Error),
+    StructuralSpecialization {
+        region: Region,
+        typ: ErrorType,
+        ability: Symbol,
+        member: Symbol,
+    },
+    WrongSpecialization {
+        region: Region,
+        ability_member: Symbol,
+        expected_opaque: Symbol,
+        found_opaque: Symbol,
+    },
+}
+
+#[derive(PartialEq, Debug, Clone)]
+pub enum Unfulfilled {
+    /// No claimed implementation of an ability for an opaque type.
+    OpaqueDoesNotImplement { typ: Symbol, ability: Symbol },
+    /// Cannot derive implementation of an ability for a structural type.
+    AdhocUnderivable {
+        typ: ErrorType,
+        ability: Symbol,
+        reason: UnderivableReason,
+    },
+    /// Cannot derive implementation of an ability for an opaque type.
+    OpaqueUnderivable {
+        typ: ErrorType,
+        ability: Symbol,
+        opaque: Symbol,
+        derive_region: Region,
+        reason: UnderivableReason,
+    },
+}
+
+#[derive(PartialEq, Debug, Clone)]
+pub enum UnderivableReason {
+    NotABuiltin,
+    /// The surface type is not derivable
+    SurfaceNotDerivable,
+    /// A nested type is not derivable
+    NestedNotDerivable(ErrorType),
+}