ran into another type inference problem

src/eval.rs

@@ -39,6 +39,7 @@ mod primtype;
 mod value;
 
 use cranelift_module::ModuleError;
+use internment::ArcIntern;
 pub use primop::PrimOpError;
 pub use primtype::PrimitiveType;
 pub use value::Value;
@@ -76,6 +77,15 @@ pub enum EvalError<IR> {
     UnknownPrimType(#[from] UnknownPrimType),
     #[error("Variable lookup failed for {1} at {0:?}")]
     LookupFailed(crate::syntax::Location, String),
+    #[error("Attempted to call something that wasn't a function at {0:?} (it was a {1})")]
+    NotAFunction(crate::syntax::Location, Value<IR>),
+    #[error("Wrong argument call for function ({1:?}) at {0:?}; expected {2}, saw {3}")]
+    WrongArgCount(
+        crate::syntax::Location,
+        Option<ArcIntern<String>>,
+        usize,
+        usize,
+    ),
 }
 
 impl<IR1: Clone, IR2: Clone> PartialEq<EvalError<IR1>> for EvalError<IR2> {
@@ -129,6 +139,16 @@ impl<IR1: Clone, IR2: Clone> PartialEq<EvalError<IR1>> for EvalError<IR2> {
                 EvalError::UnknownPrimType(b) => a == b,
                 _ => false,
             },
+
+            EvalError::NotAFunction(a, b) => match other {
+                EvalError::NotAFunction(x, y) => a == x && b == y,
+                _ => false,
+            },
+
+            EvalError::WrongArgCount(a, b, c, d) => match other {
+                EvalError::WrongArgCount(w, x, y, z) => a == w && b == x && c == y && d == z,
+                _ => false,
+            },
         }
     }
 }