CWG2372 Incorrect matching rules for block-scope extern declarations

Author: Dawn Perchik

source/basic.tex

@@ -2440,8 +2440,12 @@
 \pnum
 The name of a function declared in block scope and the name of a variable declared by a
 block scope \tcode{extern} declaration have linkage. If there is a visible declaration
-of an entity with linkage having the same name and type, ignoring entities declared
-outside the innermost enclosing namespace scope, the block scope declaration declares
+of an entity with linkage, ignoring entities declared
+outside the innermost enclosing namespace scope,
+such that the block scope declaration would be
+a (possibly ill-formed) redeclaration
+if the two declarations appeared in the same declarative region,
+the block scope declaration declares
 that same entity and receives the linkage of the previous declaration. If there is more
 than one such matching entity, the program is ill-formed. Otherwise, if no matching
 entity is found, the block scope entity receives external linkage.
@@ -2450,9 +2454,11 @@
 \begin{example}
 \begin{codeblock}
 static void f();
+extern "C" void h();
 static int i = 0;               // \#1
 void g() {
   extern void f();              // internal linkage
+  extern void h();              // C language linkage
   int i;                        // \#2: \tcode{i} has no linkage
   {
     extern void f();            // internal linkage