diff --git a/pallene/coder.lua b/pallene/coder.lua
index 31812525..bed55f10 100644
--- a/pallene/coder.lua
+++ b/pallene/coder.lua
@@ -1452,7 +1452,7 @@ gen_cmd["BuiltinMathCeil"] = function(self, cmd, _func)
     local dst = self:c_var(cmd.dsts[1])
     local v = self:c_value(cmd.srcs[1])
     local line = cmd.loc.line
-    return util.render([[ $dst = pallene_math_ceil(L, PALLENE_SOURCE_FILE, $line, $v); ]], { 
+    return util.render([[ $dst = pallene_math_ceil(L, PALLENE_SOURCE_FILE, $line, $v); ]], {
         dst = dst, v = v, line = C.integer(line) })
 end
 
@@ -1460,7 +1460,7 @@ gen_cmd["BuiltinMathFloor"] = function(self, cmd, _func)
     local dst = self:c_var(cmd.dsts[1])
     local v = self:c_value(cmd.srcs[1])
     local line = cmd.loc.line
-    return util.render([[ $dst = pallene_math_floor(L, PALLENE_SOURCE_FILE, $line, $v); ]], { 
+    return util.render([[ $dst = pallene_math_floor(L, PALLENE_SOURCE_FILE, $line, $v); ]], {
         dst = dst, v = v, line = C.integer(line) })
 end
 
@@ -1502,7 +1502,7 @@ gen_cmd["BuiltinMathModf"] = function(self, cmd, _func)
     local dst2 = self:c_var(cmd.dsts[2])
     local v = self:c_value(cmd.srcs[1])
     local line = cmd.loc.line
-    return util.render([[ $dst1 = pallene_math_modf(L, PALLENE_SOURCE_FILE, $line, $v, &$dst2); ]], { 
+    return util.render([[ $dst1 = pallene_math_modf(L, PALLENE_SOURCE_FILE, $line, $v, &$dst2); ]], {
         dst1 = dst1, dst2 = dst2, v = v, line = C.integer(line) })
 end
 
diff --git a/pallene/translator.lua b/pallene/translator.lua
index 7f442cc4..8b81382c 100644
--- a/pallene/translator.lua
+++ b/pallene/translator.lua
@@ -101,7 +101,7 @@ function translator.translate(input, prog_ast)
     -- Whatever characters that were not included in the partials should be added.
     instance:add_previous(#input)
 
-    -- This prepends any compatibility shims we need. 
+    -- This prepends any compatibility shims we need.
     instance:prepend_compatibility_code()
 
     return table.concat(instance.partials)
diff --git a/run-lint b/run-lint
index b60c9db7..d26d1dac 100755
--- a/run-lint
+++ b/run-lint
@@ -1,5 +1,6 @@
 #!/bin/sh
 
+space=' '
 tab='	'
 ok=yes
 
@@ -22,11 +23,19 @@ for file in \
     examples/*/*.lua examples/*/*.pln \
     vm/src/pallene_core.c vm/src/pallene_core.h
 do
-    if grep "^$tab" "$file"; then
+    if grep --line-number "[$space$tab]$" "$file"; then
+        # Forbid trailing whitespace because some editors like to automatically delete it.
+        # Such whitespace can cause spurious diffs later down the road, when someone is working on
+        # an unrelated pull request and their editor "helpfully" deletes the trailing whitespace.
+        error "File $file has a line that ends in whitespace"
+    fi
+
+    if grep --line-number "^$tab" "$file"; then
+        # Standardize on spaces because mixing tabs and spaces is endless pain.
         error "File $file has tab-based indentation"
     fi
 
-    if ! grep --quiet 'SPDX-License-Identifier' "$file"; then
+    if ! grep --line-number --quiet 'SPDX-License-Identifier' "$file"; then
         error "File $file is missing a copyright header"
     fi
 done
diff --git a/vm/src/pallene_core.h b/vm/src/pallene_core.h
index a6c61e5c..872d3a78 100644
--- a/vm/src/pallene_core.h
+++ b/vm/src/pallene_core.h
@@ -220,9 +220,9 @@ lua_Integer pallene_shiftR(lua_Integer x, lua_Integer y)
 }
 
 /* Some Lua math functions return integer if the result fits in integer, or float if it doesn't.
- * In Pallene, we can't return different types, so we instead raise an error if it doesn't fit 
+ * In Pallene, we can't return different types, so we instead raise an error if it doesn't fit
  * See also: pushnumint in lmathlib */
-static inline 
+static inline
 lua_Integer pallene_checked_float_to_int(lua_State *L, const char* file, int line, lua_Number d)
 {
     lua_Integer n;