Don't print format string with errors at compile time

compiler/noirc_frontend/src/hir/comptime/errors.rs

@@ -240,6 +240,9 @@ pub enum InterpreterError {
         err: Box<TypeCheckError>,
         location: Location,
     },
+    CannotInterpretFormatStringWithErrors {
+        location: Location,
+    },
 
     // These cases are not errors, they are just used to prevent us from running more code
     // until the loop can be resumed properly. These cases will never be displayed to users.
@@ -315,7 +318,8 @@ impl InterpreterError {
             | InterpreterError::TypeAnnotationsNeededForMethodCall { location }
             | InterpreterError::CannotResolveExpression { location, .. }
             | InterpreterError::CannotSetFunctionBody { location, .. }
-            | InterpreterError::UnknownArrayLength { location, .. } => *location,
+            | InterpreterError::UnknownArrayLength { location, .. }
+            | InterpreterError::CannotInterpretFormatStringWithErrors { location } => *location,
 
             InterpreterError::FailedToParseMacro { error, file, .. } => {
                 Location::new(error.span(), *file)
@@ -664,6 +668,12 @@ impl<'a> From<&'a InterpreterError> for CustomDiagnostic {
                 let secondary = format!("Evaluating the length failed with: `{err}`");
                 CustomDiagnostic::simple_error(msg, secondary, location.span)
             }
+            InterpreterError::CannotInterpretFormatStringWithErrors { location } => {
+                let msg = "Cannot interpret format string with errors".to_string();
+                let secondary =
+                    "Some of the variables to interpolate could not be evaluated".to_string();
+                CustomDiagnostic::simple_error(msg, secondary, location.span)
+            }
         }
     }
 }

compiler/noirc_frontend/src/hir/comptime/interpreter.rs

@@ -665,8 +665,12 @@ impl<'local, 'interner> Interpreter<'local, 'interner> {
                             result.push_str(&value.display(self.elaborator.interner).to_string());
                         }
                     } else {
-                        // If we can't find a value for this fragment it means it already errored
-                        // when trying to type-check it, and we don't want to error again or panic here.
+                        // If we can't find a value for this fragment it means the interpolated value was not
+                        // found or it errored. In this case we error here as well.
+                        let location = self.elaborator.interner.expr_location(&id);
+                        return Err(InterpreterError::CannotInterpretFormatStringWithErrors {
+                            location,
+                        });
                     }
                 }
             }