Add a NEVER() to an unreachable branch in the DROP COLUMN logic.

FossilOrigin-Name: 963f498ae64cf7530fb7a405fa476c411ad66523f62f5eefa5a16596cd19a481

manifest

@@ -1,5 +1,5 @@
-C Add\smissing\sVdbeCoverage()\smacros.
-D 2021-02-18T23:53:47.042
+C Add\sa\sNEVER()\sto\san\sunreachable\sbranch\sin\sthe\sDROP\sCOLUMN\slogic.
+D 2021-02-19T02:30:02.782
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -475,7 +475,7 @@ F spec.template 86a4a43b99ebb3e75e6b9a735d5fd293a24e90ca
 F sqlite.pc.in 42b7bf0d02e08b9e77734a47798d1a55a9e0716b
 F sqlite3.1 fc7ad8990fc8409983309bb80de8c811a7506786
 F sqlite3.pc.in 48fed132e7cb71ab676105d2a4dc77127d8c1f3a
-F src/alter.c 7f9453d11a53808eececd397fc98bfa0431a47838322f944a5026861582503cf
+F src/alter.c b2a3c89c5bcf5251cfb786e608381ef506d71a9f1c375e277124cc924e4546f9
 F src/analyze.c 01c6c6765cb4d40b473b71d85535093730770bb186f2f473abac25f07fcdee5c
 F src/attach.c e80162a47411f296bea550ed8fafd730481f4aa71e89ece23ba9c957eed15d4a
 F src/auth.c 08954fdc4cc2da5264ba5b75cfd90b67a6fc7d1710a02ccf917c38eadec77853
@@ -1902,7 +1902,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 68bcde7ab57b2d4bdcfb2f6c7134a0b01a504b2e7cdf6ee5bf0df70fb4a517b0
-R 152516a53a5f57ac32212c9aee0d7991
+P 9bb720e6590482bc9c2fbb273738808209e9651710dbee7572b0348cadf87e68
+R c0fbd4f44b1d4f87e911757503e8d30c
 U drh
-Z d661d689a5e017081615544903b6cdf3
+Z 525012fbf3fca5430284eed456ca18e8

manifest.uuid

@@ -1 +1 @@
-9bb720e6590482bc9c2fbb273738808209e9651710dbee7572b0348cadf87e68
+963f498ae64cf7530fb7a405fa476c411ad66523f62f5eefa5a16596cd19a481

src/alter.c

@@ -1849,7 +1849,7 @@ void sqlite3AlterDropColumn(Parse *pParse, SrcList *pSrc, Token *pName){
   /* Look up the table being altered. */
   assert( pParse->pNewTable==0 );
   assert( sqlite3BtreeHoldsAllMutexes(db) );
-  if( db->mallocFailed ) goto exit_drop_column;
+  if( NEVER(db->mallocFailed) ) goto exit_drop_column;
   pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
   if( !pTab ) goto exit_drop_column;