fix Issue 13742 - undefined reference to __coverage

src/dmd/glue.d

@@ -386,13 +386,10 @@ void genObjFile(Module m, bool multiobj)
     if (global.params.cov)
     {
         /* Create coverage identifier:
-         *  private uint[numlines] __coverage;
+         *  uint[numlines] __coverage;
          */
-        m.cov = symbol_calloc("__coverage");
-        m.cov.Stype = type_fake(TYint);
-        m.cov.Stype.Tmangle = mTYman_c;
-        m.cov.Stype.Tcount++;
-        m.cov.Sclass = SCstatic;
+        m.cov = toSymbolX(m, "__coverage", SCglobal, type_fake(TYint), "Z");
+        m.cov.Stype.Tmangle = mTYman_d;
         m.cov.Sfl = FLdata;
 
         scope dtb = new DtBuilder();
@@ -1575,4 +1572,3 @@ elem *toEfilenamePtr(Module m)
     Symbol* s = toStringSymbol(id, len, 1);
     return el_ptr(s);
 }
-

test/runnable/extra-files/lib13742a.d

@@ -0,0 +1,6 @@
+module lib13742a;
+
+void performLocked(alias PROC)()
+{
+    PROC();
+}

test/runnable/extra-files/lib13742b.d

@@ -0,0 +1,8 @@
+module lib13742b;
+import lib13742a;
+
+void clear()
+{
+    void foo() {} // nested function
+    performLocked!foo; // template from other module (preceding on command line)
+}

test/runnable/extra-files/test13742.d

@@ -0,0 +1,6 @@
+import lib13742b;
+
+void main()
+{
+    clear();
+}

test/runnable/test13742.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+
+set -x # debug windows issues
+set -ueo pipefail
+
+src=runnable${SEP}extra-files
+dir=${RESULTS_DIR}${SEP}runnable
+output_file=${dir}/test13742.sh.out
+
+if [ $OS == "win32" -o  $OS == "win64" ]; then
+    LIBEXT=.lib
+    OBJ=.obj
+else
+    LIBEXT=.a
+    OBJ=.o
+fi
+
+$DMD -m${MODEL} -I${src} -lib -cov -of${dir}${SEP}test13742${LIBEXT} ${src}${SEP}lib13742a.d ${src}${SEP}lib13742b.d
+$DMD -m${MODEL} -I${src} -cov -of${dir}${SEP}test13742${EXE} ${src}${SEP}test13742.d ${dir}${SEP}test13742${LIBEXT}
+
+${RESULTS_DIR}/runnable/test13742${EXE} --DRT-covopt=dstpath:${dir}${SEP}
+
+rm ${RESULTS_DIR}/runnable/{runnable-extra-files-{lib13742a,lib13742b,test13742}.lst,test13742{${OBJ},${LIBEXT},${EXE}}}
+
+echo Success > ${output_file}