From dcd4f0709ff6bc46fb9bc1c3873db795f9ff9a55 Mon Sep 17 00:00:00 2001
From: James Shubin <james@shubin.ca>
Date: Thu, 5 Jun 2025 23:00:56 -0400
Subject: [PATCH] lang: ast: Provide better error reporting for scope errors

Print these file and line numbers when we can!
---
 lang/ast/structs.go | 15 ++++++++++-----
 lang/ast/util.go    | 13 +++++++++++++
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/lang/ast/structs.go b/lang/ast/structs.go
index f3c2daa8..69ab85e5 100644
--- a/lang/ast/structs.go
+++ b/lang/ast/structs.go
@@ -6828,7 +6828,8 @@ func (obj *StmtInclude) SetScope(scope *interfaces.Scope) error {
 
 	stmt, exists := scope.Classes[obj.Name]
 	if !exists {
-		return fmt.Errorf("class `%s` does not exist in this scope", obj.Name)
+		err := fmt.Errorf("class `%s` does not exist in this scope", obj.Name)
+		return highlightHelper(obj, obj.data.Logf, err)
 	}
 	class, ok := stmt.(*StmtClass)
 	if !ok {
@@ -10468,7 +10469,8 @@ func (obj *ExprCall) SetScope(scope *interfaces.Scope, sctx map[string]interface
 				if obj.data.Debug || true { // TODO: leave this on permanently?
 					lambdaScopeFeedback(obj.scope, obj.data.Logf)
 				}
-				return fmt.Errorf("lambda `$%s` does not exist in this scope", prefixedName)
+				err := fmt.Errorf("lambda `$%s` does not exist in this scope", prefixedName)
+				return highlightHelper(obj, obj.data.Logf, err)
 			}
 			target = f
 		}
@@ -10484,7 +10486,8 @@ func (obj *ExprCall) SetScope(scope *interfaces.Scope, sctx map[string]interface
 			if obj.data.Debug || true { // TODO: leave this on permanently?
 				functionScopeFeedback(obj.scope, obj.data.Logf)
 			}
-			return fmt.Errorf("func `%s` does not exist in this scope", prefixedName)
+			err := fmt.Errorf("func `%s` does not exist in this scope", prefixedName)
+			return highlightHelper(obj, obj.data.Logf, err)
 		}
 		target = f
 	}
@@ -11232,7 +11235,8 @@ func (obj *ExprVar) SetScope(scope *interfaces.Scope, sctx map[string]interfaces
 		if obj.data.Debug || true { // TODO: leave this on permanently?
 			variableScopeFeedback(obj.scope, obj.data.Logf)
 		}
-		return fmt.Errorf("var `$%s` does not exist in this scope", obj.Name)
+		err := fmt.Errorf("var `$%s` does not exist in this scope", obj.Name)
+		return highlightHelper(obj, obj.data.Logf, err)
 	}
 
 	obj.scope.Variables[obj.Name] = target
@@ -11292,7 +11296,8 @@ func (obj *ExprVar) Infer() (*types.Type, []*interfaces.UnificationInvariant, er
 	// lookup value from scope
 	expr, exists := obj.scope.Variables[obj.Name]
 	if !exists {
-		return nil, nil, fmt.Errorf("var `%s` does not exist in this scope", obj.Name)
+		err := fmt.Errorf("var `%s` does not exist in this scope", obj.Name)
+		return nil, nil, highlightHelper(obj, obj.data.Logf, err)
 	}
 
 	// This child call to Infer is an outlier to the common pattern where
diff --git a/lang/ast/util.go b/lang/ast/util.go
index 10d5dc66..1e6ae6eb 100644
--- a/lang/ast/util.go
+++ b/lang/ast/util.go
@@ -562,6 +562,19 @@ func lambdaScopeFeedback(scope *interfaces.Scope, logf func(format string, v ...
 	}
 }
 
+// highlightHelper give the user better file/line number feedback.
+func highlightHelper(node interfaces.Node, logf func(format string, v ...interface{}), err error) error {
+	displayer, ok := node.(interfaces.TextDisplayer)
+	if ok {
+		if highlight := displayer.HighlightText(); highlight != "" {
+			logf("%s: %s", err.Error(), highlight)
+		}
+		//return fmt.Errorf("%s: %s", err.Error(), displayer.Byline())
+	}
+
+	return err
+}
+
 // Textarea stores the coordinates of a statement or expression in the form of a
 // starting line/column and ending line/column.
 type Textarea struct {