Do not load Path call receiver if known to be unused

src/compiler/crystal/codegen/call.cr

@@ -55,9 +55,18 @@ class Crystal::CodeGenVisitor
 
     obj = node.obj
 
-    # Always accept obj: even if it's not passed as self this might
-    # involve intermediate calls with side effects.
-    if obj
+    case obj
+    when Path
+      # Non-generic metaclasses and lib types do not need a self argument,
+      # reading them should not have side effects unless `obj` turns out to be
+      # a constant with an initializer (e.g. `A = (puts 1; Int32)` has a side
+      # effect).
+      if obj.type.passed_as_self? || obj.target_const
+        request_value(obj)
+      end
+    when ASTNode
+      # Always accept obj: even if it's not passed as self this might
+      # involve intermediate calls with side effects.
       request_value(obj)
     end