Fix tee_local typechecking bug w/ polymorphic stack (#587)

The previous type-checking code just made sure the value on the top of
the stack is the correct type. This isn't sufficient when the stack is
polymorphic, because the concrete type is not pushed onto the stack.

2 files changed, 15 insertions, 4 deletions

diff --git a/src/type-checker.cc b/src/type-checker.cc
index 72b86cb4..7c14b6db 100644
--- a/src/type-checker.cc
+++ b/src/type-checker.cc
@@ -528,10 +528,8 @@ Result TypeChecker::OnTryBlock(const TypeVector* sig) {
 
 Result TypeChecker::OnTeeLocal(Type type) {
   Result result = Result::Ok;
-  Type value = Type::Any;
-  COMBINE_RESULT(result, CheckTypeStackLimit(1, "tee_local"));
-  COMBINE_RESULT(result, TopType(&value));
-  COMBINE_RESULT(result, CheckType(value, type, "tee_local"));
+  COMBINE_RESULT(result, PopAndCheck1Type(type, "tee_local"));
+  PushType(type);
   return result;
 }
 
diff --git a/test/regress/regress-10.txt b/test/regress/regress-10.txt
new file mode 100644
index 00000000..299f73a9
--- /dev/null
+++ b/test/regress/regress-10.txt
@@ -0,0 +1,13 @@
+;;; ERROR: 1
+(module
+  (func
+    (local i32)
+    block
+      unreachable
+      tee_local 0
+    end))
+(;; STDERR ;;;
+out/test/regress/regress-10.txt:7:7: error: type stack at end of block is 1, expected 0
+      tee_local 0
+      ^^^^^^^^^^^
+;;; STDERR ;;)