From 97eb4b6e3ea42e78495e673c2cc4c38f3776f837 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Fri, 18 Sep 2020 12:02:37 -0700
Subject: [PATCH] Fix silent error in set_mangled_name

---
 code/compiler/13/type_env.cpp             | 11 ++++++-----
 content/blog/13_compiler_cleanup/index.md | 10 +++-------
 2 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/code/compiler/13/type_env.cpp b/code/compiler/13/type_env.cpp
index 6f4fe6a..0c0ddef 100644
--- a/code/compiler/13/type_env.cpp
+++ b/code/compiler/13/type_env.cpp
@@ -34,12 +34,13 @@ bool type_env::is_global(const std::string& name) const {
 
 void type_env::set_mangled_name(const std::string& name, const std::string& mangled) {
     auto it = names.find(name);
-    if(it != names.end()) {
-        // Local names shouldn't need mangling.
-        assert(it->second.vis == visibility::global);
 
-        it->second.mangled_name = mangled;
-    }
+    // Can't set mangled name for non-existent variable.
+    assert(it != names.end());
+    // Local names shouldn't need mangling.
+    assert(it->second.vis == visibility::global);
+
+    it->second.mangled_name = mangled;
 }
 
 const std::string& type_env::get_mangled_name(const std::string& name) const {
diff --git a/content/blog/13_compiler_cleanup/index.md b/content/blog/13_compiler_cleanup/index.md
index 72d56a8..ee28252 100644
--- a/content/blog/13_compiler_cleanup/index.md
+++ b/content/blog/13_compiler_cleanup/index.md
@@ -535,7 +535,7 @@ In general, this change is also rather mechanical, but, to
 maintain a balance between exceptions and assertions, here
 are a couple more assertions from `type_env`:
 
-{{< codelines "C++" "compiler/13/type_env.cpp" 76 77 >}}
+{{< codelines "C++" "compiler/13/type_env.cpp" 77 78 >}}
 
 Once again, it should not be possible for the compiler
 to try generalize the type of a variable that doesn't
@@ -621,7 +621,7 @@ Now that we've started using assertions, I also think it's worth
 to put our new invariant -- "only global definitions have mangled
 names" -- into code:
 
-{{< codelines "C++" "compiler/13/type_env.cpp" 35 43 >}}
+{{< codelines "C++" "compiler/13/type_env.cpp" 35 44 >}}
 
 Furthermore, we'll _require_ that a global definition
 has a mangled name. This way, we can be more confident
@@ -635,7 +635,7 @@ we add another assertion: if an environment scope doesn't
 contain a mangled name for a variable, then it _must_
 have a parent. We end up with the following:
 
-{{< codelines "C++" "compiler/13/type_env.cpp" 45 51 >}}
+{{< codelines "C++" "compiler/13/type_env.cpp" 46 52 >}}
 
 Since looking up a mangled name for non-global variable
 will now result in an assertion failure, we have to change
@@ -866,7 +866,3 @@ name with `f_`, much like `create_custom_function`:
 I think that's enough. If we chose to turn more compiler
 data structures into classes, I think we would've quickly drowned
 in one-line getter and setter methods.
-
-{{< todo >}}
-Assertion failure on `set_mangled_name` on non-existent function,
-too. {{< /todo >}}