From 899d61755e8f9b35b47986434e55af2b818fbda7 Mon Sep 17 00:00:00 2001
From: Iain Buclaw <ibuclaw@gdcproject.org>
Date: Wed, 26 May 2021 00:45:14 +0200
Subject: [PATCH] fix Issue 21970 - importC: Error: variable extern symbols
 cannot have initializers

---
 src/dmd/cparse.d                  | 6 ++++--
 test/compilable/imports/cstuff1.c | 5 +++++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/dmd/cparse.d b/src/dmd/cparse.d
index 36767c23e671..a421f10c2fa5 100644
--- a/src/dmd/cparse.d
+++ b/src/dmd/cparse.d
@@ -1541,8 +1541,6 @@ final class CParser(AST) : Parser!AST
                     hasInitializer = true;
                     initializer = cparseInitializer();
                 }
-                else
-                    initializer = new AST.VoidInitializer(token.loc);
                 // declare the symbol
                 assert(id);
                 if (dt.isTypeFunction())
@@ -1553,6 +1551,10 @@ final class CParser(AST) : Parser!AST
                 }
                 else
                 {
+                    // Give non-extern variables an implicit void initializer
+                    // if one has not been explicitly set.
+                    if (!hasInitializer && !(specifier.scw & SCW.xextern))
+                        initializer = new AST.VoidInitializer(token.loc);
                     s = new AST.VarDeclaration(token.loc, dt, id, initializer, specifiersToSTC(level, specifier));
                 }
             }
diff --git a/test/compilable/imports/cstuff1.c b/test/compilable/imports/cstuff1.c
index d70f69b37eba..959fa4433c70 100644
--- a/test/compilable/imports/cstuff1.c
+++ b/test/compilable/imports/cstuff1.c
@@ -345,6 +345,11 @@ union U21963
 const int test21967a(void);
 const int *test21967b(void);
 
+/********************************/
+// https://issues.dlang.org/show_bug.cgi?id=21970
+extern int test21970a;
+extern char *test21970b;
+
 /********************************/
 
 void test__func__()