fix let: glob cast from string

crates/nu-engine/src/compile/keyword.rs

@@ -2,7 +2,7 @@ use nu_protocol::{
     ast::{Block, Call, Expr, Expression},
     engine::StateWorkingSet,
     ir::Instruction,
-    IntoSpanned, RegId, VarId,
+    IntoSpanned, RegId, Type, VarId,
 };
 
 use super::{compile_block, compile_expression, BlockBuilder, CompileError, RedirectModes};
@@ -302,6 +302,8 @@ pub(crate) fn compile_let(
     let block_id = block_arg.as_block().ok_or_else(invalid)?;
     let block = working_set.get_block(block_id);
 
+    let variable = working_set.get_variable(var_id);
+
     compile_block(
         working_set,
         builder,
@@ -311,6 +313,17 @@ pub(crate) fn compile_let(
         io_reg,
     )?;
 
+    // If the variable is a glob type variable, we should cast it with GlobFrom
+    if variable.ty == Type::Glob {
+        builder.push(
+            Instruction::GlobFrom {
+                src_dst: io_reg,
+                no_expand: true,
+            }
+            .into_spanned(call.head),
+        )?;
+    }
+
     builder.push(
         Instruction::StoreVariable {
             var_id,

crates/nu-engine/src/eval_ir.rs

@@ -503,8 +503,14 @@ fn eval_instruction<D: DebugContext>(
         }
         Instruction::GlobFrom { src_dst, no_expand } => {
             let string_value = ctx.collect_reg(*src_dst, *span)?;
-            let string = string_value.into_string()?;
-            let glob_value = Value::glob(string, *no_expand, *span);
+            let glob_value = if matches!(string_value, Value::Glob { .. }) {
+                // It already is a glob, so don't touch it.
+                string_value
+            } else {
+                // Treat it as a string, then cast
+                let string = string_value.into_string()?;
+                Value::glob(string, *no_expand, *span)
+            };
             ctx.put_reg(*src_dst, glob_value.into_pipeline_data());
             Ok(Continue)
         }

crates/nu-protocol/src/ir/mod.rs

@@ -169,7 +169,8 @@ pub enum Instruction {
     /// Append a value onto the end of a string. Uses `to_expanded_string(", ", ...)` on the value.
     /// Used for string interpolation literals. Not the same thing as the `++` operator.
     StringAppend { src_dst: RegId, val: RegId },
-    /// Convert a string into a glob. Used for glob interpolation.
+    /// Convert a string into a glob. Used for glob interpolation and setting glob variables. If the
+    /// value is already a glob, it won't be modified (`no_expand` will have no effect).
     GlobFrom { src_dst: RegId, no_expand: bool },
     /// Push a value onto the end of a list. Used to construct list literals.
     ListPush { src_dst: RegId, item: RegId },