Fix #6240

crates/compiler/load/tests/test_reporting.rs

@@ -14426,4 +14426,76 @@ All branches in an `if` must have the same type!
     //     ),
     //     @r""
     // );
+
+    test_report!(
+        issue_6240_1,
+        indoc!(
+            r"
+            {}.abcde
+            "
+        ),
+        @r###"
+    ── TYPE MISMATCH in /code/proj/Main.roc ────────────────────────────────────────
+    
+    This record doesn’t have a `abcde` field:
+    
+    4│      {}.abcde
+            ^^^^^^^^
+    
+    In fact, it’s a record with no fields at all!
+    "###
+    );
+
+    test_report!(
+        issue_6240_2,
+        indoc!(
+            r#"
+            ("", "").abcde
+            "#
+        ),
+        @r###"
+    ── TYPE MISMATCH in /code/proj/Main.roc ────────────────────────────────────────
+    
+    This expression is used in an unexpected way:
+    
+    4│      ("", "").abcde
+            ^^^^^^^^^^^^^^
+    
+    It is a tuple of type:
+    
+        (
+            Str,
+            Str,
+        )a
+    
+    But you are trying to use it as:
+    
+        { abcde : * }b
+    "###
+    );
+
+    test_report!(
+        issue_6240_3,
+        indoc!(
+            r"
+            {}.0
+            "
+        ),
+        @r###"
+    ── TYPE MISMATCH in /code/proj/Main.roc ────────────────────────────────────────
+
+    This expression is used in an unexpected way:
+    
+    4│      {}.0
+            ^^^^
+    
+    It is a record of type:
+    
+        {}
+    
+    But you are trying to use it as:
+    
+        (*)b
+    "###
+    );
 }

crates/compiler/mono/src/ir.rs

@@ -4978,12 +4978,17 @@ pub fn with_hole<'a>(
                 }
             }
 
+            let struct_index = match index {
+                Some(index) => index,
+                None => return runtime_error(env, "No such field in record"),
+            };
+
             compile_struct_like_access(
                 env,
                 procs,
                 layout_cache,
                 field_layouts,
-                index.expect("field not in its own type") as _,
+                struct_index,
                 *loc_expr,
                 record_var,
                 hole,
@@ -5076,12 +5081,17 @@ pub fn with_hole<'a>(
                 }
             }
 
+            let tuple_index = match final_index {
+                Some(index) => index as u64,
+                None => return runtime_error(env, "No such index in tuple"),
+            };
+
             compile_struct_like_access(
                 env,
                 procs,
                 layout_cache,
                 field_layouts,
-                final_index.expect("elem not in its own type") as u64,
+                tuple_index,
                 *loc_expr,
                 tuple_var,
                 hole,
@@ -8055,7 +8065,10 @@ fn can_reuse_symbol<'a>(
                 .enumerate()
                 .find_map(|(current, (label, _, _))| (label == *field).then_some(current));
 
-            let struct_index = index.expect("field not in its own type");
+            let struct_index = match index {
+                Some(index) => index as u64,
+                None => return NotASymbol,
+            };
 
             let struct_symbol = possible_reuse_symbol_or_specialize(
                 env,