--errorMax:0 means: unlimited

compiler/commands.nim

@@ -618,10 +618,14 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
     expectNoArg(conf, switch, arg, pass, info)
     incl(conf.globalOptions, optRun)
   of "errormax":
-    # Note: `nim check` (etc) can overwrite this;
-    # `0` is meaningless and has same effect as `1`
     expectArg(conf, switch, arg, pass, info)
-    conf.errorMax = parseInt(arg)
+    conf.errorMax = block:
+      # Note: `nim check` (etc) can overwrite this.
+      # `0` is meaningless, give it a useful meaning as in clang's -ferror-limit
+      # If user doesn't set this flag and the code doesn't either, it'd
+      # have the same effect as errorMax = 1
+      let ret = parseInt(arg)
+      if ret == 0: high(int) else: ret
   of "verbosity":
     expectArg(conf, switch, arg, pass, info)
     let verbosity = parseInt(arg)

doc/advopt.txt

@@ -103,7 +103,7 @@ Advanced options:
                             value = number of processors (0 for auto-detect)
   --incremental:on|off      only recompile the changed modules (experimental!)
   --verbosity:0|1|2|3       set Nim's verbosity level (1 is default)
-  --errorMax:int            stop after n (>=1) errors in semantic pass
+  --errorMax:int            stop after n errors in semantic pass; 0 means unlimited
   --experimental:$1
                             enable experimental language feature
   -v, --version             show detailed version information