Refine error position for missing indexer.

src/engine.rs

@@ -248,7 +248,6 @@ pub const FN_ANONYMOUS: &str = "anon$";
 pub const OP_EQUALS: &str = "==";
 
 /// Standard method function for containment testing.
-///
 /// The `in` operator is implemented as a call to this method.
 pub const OP_CONTAINS: &str = "contains";
 
@@ -1293,10 +1292,11 @@ impl Engine {
                             let hash_set =
                                 FnCallHashes::from_native(crate::calc_fn_hash(FN_IDX_SET, 3));
                             let args = &mut [target, &mut idx_val_for_setter, &mut new_val];
+                            let pos = Position::NONE;
 
                             self.exec_fn_call(
-                                mods, state, lib, FN_IDX_SET, hash_set, args, is_ref, true,
+                                mods, state, lib, FN_IDX_SET, hash_set, args, is_ref, true, pos,
-                                new_pos, None, level,
+                                None, level,
                             )?;
                         }
 
@@ -1425,10 +1425,11 @@ impl Engine {
                                 let args = &mut [target, &mut name.into(), &mut new_val];
                                 let hash_set =
                                     FnCallHashes::from_native(crate::calc_fn_hash(FN_IDX_SET, 3));
+                                let pos = Position::NONE;
 
                                 self.exec_fn_call(
                                     mods, state, lib, FN_IDX_SET, hash_set, args, is_ref, true,
-                                    *pos, None, level,
+                                    pos, None, level,
                                 )
                                 .map_err(
                                     |idx_err| match *idx_err {
@@ -1972,6 +1973,7 @@ impl Engine {
             _ if indexers => {
                 let args = &mut [target, &mut idx];
                 let hash_get = FnCallHashes::from_native(crate::calc_fn_hash(FN_IDX_GET, 2));
+                let idx_pos = Position::NONE;
 
                 self.exec_fn_call(
                     mods, state, lib, FN_IDX_GET, hash_get, args, true, true, idx_pos, None, level,
@@ -1980,7 +1982,11 @@ impl Engine {
             }
 
             _ => EvalAltResult::ErrorIndexingType(
-                self.map_type_name(target.type_name()).into(),
+                format!(
+                    "{} [{}]",
+                    self.map_type_name(target.type_name()),
+                    self.map_type_name(idx.type_name())
+                ),
                 Position::NONE,
             )
             .into(),

src/error.rs

@@ -59,8 +59,7 @@ pub enum EvalAltResult {
     /// Bit-field indexing out-of-bounds.
     /// Wrapped values are the current number of bits in the bit-field and the index number.
     ErrorBitFieldBounds(usize, INT, Position),
-    /// Trying to index into a type that is not an array, an object map, or a string, and has no
+    /// Trying to index into a type that has no indexer function defined. Wrapped value is the type name.
-    /// indexer function defined. Wrapped value is the type name.
     ErrorIndexingType(String, Position),
     /// The `for` statement encounters a type that is not an iterator.
     ErrorFor(Position),
@@ -106,9 +105,7 @@ impl EvalAltResult {
             Self::ErrorFunctionNotFound(_, _) => "Function not found",
             Self::ErrorUnboundThis(_) => "'this' is not bound",
             Self::ErrorMismatchDataType(_, _, _) => "Data type is incorrect",
-            Self::ErrorIndexingType(_, _) => {
+            Self::ErrorIndexingType(_, _) => "No indexer of the appropriate types defined",
-                "Indexing can only be performed on an array, an object map, a string, or a type with an indexer function defined"
-            }
             Self::ErrorArrayBounds(0, _, _) => "Empty array has nothing to access",
             Self::ErrorArrayBounds(_, _, _) => "Array index out of bounds",
             Self::ErrorStringBounds(0, _, _) => "Empty string has nothing to index",
@@ -175,7 +172,7 @@ impl fmt::Display for EvalAltResult {
 
             Self::ErrorDotExpr(s, _) if !s.is_empty() => f.write_str(s)?,
 
-            Self::ErrorIndexingType(s, _) => write!(f, "Indexer not registered for type '{}'", s)?,
+            Self::ErrorIndexingType(s, _) => write!(f, "Indexer not registered for '{}'", s)?,
 
             Self::ErrorUnboundThis(_)
             | Self::ErrorFor(_)

src/fn_call.rs

@@ -373,7 +373,11 @@ impl Engine {
                 assert!(args.len() == 2);
 
                 EvalAltResult::ErrorIndexingType(
-                    self.map_type_name(args[0].type_name()).to_string(),
+                    format!(
+                        "{} [{}]",
+                        self.map_type_name(args[0].type_name()),
+                        self.map_type_name(args[1].type_name())
+                    ),
                     pos,
                 )
                 .into()
@@ -385,7 +389,12 @@ impl Engine {
                 assert!(args.len() == 3);
 
                 EvalAltResult::ErrorIndexingType(
-                    self.map_type_name(args[0].type_name()).to_string(),
+                    format!(
+                        "{} [{}] = {}",
+                        self.map_type_name(args[0].type_name()),
+                        self.map_type_name(args[1].type_name()),
+                        self.map_type_name(args[2].type_name())
+                    ),
                     pos,
                 )
                 .into()