Better error messages.

src/ast/expr.rs

@@ -469,7 +469,10 @@ impl fmt::Debug for Expr {
                     Self::Dot(_, _, _) => "Dot",
                     Self::And(_, _) => "And",
                     Self::Or(_, _) => "Or",
-                    _ => unreachable!(),
+                    expr => unreachable!(
+                        "Self::Dot or Self::And or Self::Or expected but gets {:?}",
+                        expr
+                    ),
                 };
 
                 display_pos = *pos;

src/ast/stmt.rs

@@ -480,7 +480,11 @@ impl Stmt {
         match self {
             Self::Var(_, _, _, _) => true,
 
-            Self::FnCall(x, _) if x.name == KEYWORD_EVAL => true,
+            Self::Expr(Expr::Stmt(s)) => s.iter().all(Stmt::is_block_dependent),
+
+            Self::FnCall(x, _) | Self::Expr(Expr::FnCall(x, _)) => {
+                x.namespace.is_none() && x.name == KEYWORD_EVAL
+            }
 
             #[cfg(not(feature = "no_module"))]
             Self::Import(_, _, _) | Self::Export(_, _) => true,
@@ -500,6 +504,8 @@ impl Stmt {
         match self {
             Self::Var(expr, _, _, _) => expr.is_pure(),
 
+            Self::Expr(Expr::Stmt(s)) => s.iter().all(Stmt::is_internally_pure),
+
             #[cfg(not(feature = "no_module"))]
             Self::Import(expr, _, _) => expr.is_pure(),
             #[cfg(not(feature = "no_module"))]