Hint for shadowed std functions (#4402)

Co-authored-by: Laurenz <laurmaedje@gmail.com>

3 files changed, 31 insertions, 2 deletions

diff --git a/crates/typst/src/eval/call.rs b/crates/typst/src/eval/call.rs
index 12d024ad..a143c8ac 100644
--- a/crates/typst/src/eval/call.rs
+++ b/crates/typst/src/eval/call.rs
@@ -128,7 +128,7 @@ impl Eval for ast::FuncCall<'_> {
             (callee.eval(vm)?, args.eval(vm)?.spanned(span))
         };
 
-        let func_result = callee.clone().cast::<Func>().at(callee_span);
+        let func_result = callee.clone().cast::<Func>();
         if in_math && func_result.is_err() {
             // For non-functions in math, we wrap the arguments in parentheses.
             let mut body = Content::empty();
@@ -148,7 +148,21 @@ impl Eval for ast::FuncCall<'_> {
             ));
         }
 
-        let func = func_result?;
+        let func = func_result
+            .map_err(|mut err| {
+                if let ast::Expr::Ident(ident) = self.callee() {
+                    let ident = ident.get();
+                    if vm.scopes.check_std_shadowed(ident) {
+                        err.hint(eco_format!(
+                        "use `std.{}` to access the shadowed standard library function",
+                        ident,
+                    ));
+                    }
+                }
+                err
+            })
+            .at(callee_span)?;
+
         let point = || Tracepoint::Call(func.name().map(Into::into));
         let f = || {
             func.call(&mut vm.engine, vm.context, args)
diff --git a/crates/typst/src/foundations/scope.rs b/crates/typst/src/foundations/scope.rs
index e0ef7a72..0313df7a 100644
--- a/crates/typst/src/foundations/scope.rs
+++ b/crates/typst/src/foundations/scope.rs
@@ -87,6 +87,14 @@ impl<'a> Scopes<'a> {
                 }
             })?
     }
+
+    /// Check if an std variable is shadowed.
+    pub fn check_std_shadowed(&self, var: &str) -> bool {
+        self.base.is_some_and(|base| base.global.scope().get(var).is_some())
+            && std::iter::once(&self.top)
+                .chain(self.scopes.iter().rev())
+                .any(|scope| scope.get(var).is_some())
+    }
 }
 
 #[cold]
diff --git a/tests/suite/scripting/call.typ b/tests/suite/scripting/call.typ
index 34344608..5a5fb326 100644
--- a/tests/suite/scripting/call.typ
+++ b/tests/suite/scripting/call.typ
@@ -49,6 +49,13 @@
 // Error: 2-3 expected function, found string
 #x()
 
+--- call-shadowed-builtin-function ---
+#let image = "image"
+
+// Error: 2-7 expected function, found string
+// Hint: 2-7 use `std.image` to access the shadowed standard library function
+#image("image")
+
 --- call-bad-type-int-expr ---
 #let f(x) = x