diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index a419e63879..7ca1df6de7 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -3449,6 +3449,10 @@ fn (mut c Checker) cast_expr(mut node ast.CastExpr) ast.Type {
 			c.error('cannot cast `string` to `enum`', node.pos)
 		}
 	}
+
+	if c.pref.warn_about_allocs && to_sym.info is ast.Interface {
+		c.warn_alloc('cast to interface', node.pos)
+	}
 	node.typname = c.table.sym(node.typ).name
 	return node.typ
 }
diff --git a/vlib/v/checker/errors.v b/vlib/v/checker/errors.v
index 4a55504412..35f9673923 100644
--- a/vlib/v/checker/errors.v
+++ b/vlib/v/checker/errors.v
@@ -32,6 +32,12 @@ fn (mut c Checker) warn(s string, pos token.Pos) {
 	c.warn_or_error(s, pos, allow_warnings)
 }
 
+fn (mut c Checker) warn_alloc(s string, pos token.Pos) {
+	if !c.is_builtin_mod && c.mod !in ['strings', 'math', 'math.bits', 'builtin'] {
+		c.warn('allocation (${s})', pos)
+	}
+}
+
 fn (mut c Checker) error(message string, pos token.Pos) {
 	if (c.pref.translated || c.file.is_translated) && message.starts_with('mismatched types') {
 		// TODO: move this
@@ -178,6 +184,8 @@ fn (mut c Checker) trace[T](fbase string, x &T) {
 }
 
 fn (mut c Checker) deprecate(kind string, name string, attrs []ast.Attr, pos token.Pos) {
+	// println('deprecate kind=${kind} name=${name} attrs=$attrs')
+	// print_backtrace()
 	mut deprecation_message := ''
 	now := time.now()
 	mut after_time := now
@@ -205,6 +213,8 @@ fn (mut c Checker) deprecate(kind string, name string, attrs []ast.Attr, pos tok
 	} else if after_time == now {
 		c.warn(semicolonize('${start_message} has been deprecated', deprecation_message),
 			pos)
+		// c.warn(semicolonize('${start_message} has been deprecated!11 m=${deprecation_message}',
+		// deprecation_message), pos)
 	} else {
 		c.note(semicolonize('${start_message} will be deprecated after ${after_time.ymmdd()}, and will become an error after ${error_time.ymmdd()}',
 			deprecation_message), pos)
diff --git a/vlib/v/checker/infix.v b/vlib/v/checker/infix.v
index 078b63c059..31ddf2fcf7 100644
--- a/vlib/v/checker/infix.v
+++ b/vlib/v/checker/infix.v
@@ -850,6 +850,9 @@ fn (mut c Checker) infix_expr(mut node ast.InfixExpr) ast.Type {
 			}
 		}
 	}
+	if node.op == .plus && c.pref.warn_about_allocs {
+		c.warn_alloc('string concatenation', node.pos)
+	}
 	/*
 	if (node.left is ast.InfixExpr && node.left.op == .inc) ||
 		(node.right is ast.InfixExpr && node.right.op == .inc) {
diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index eebc54d07c..860e0ad076 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -2564,6 +2564,13 @@ fn (mut g Gen) expr_with_cast(expr ast.Expr, got_type_raw ast.Type, expected_typ
 			if exp_sym.info.is_generic {
 				fname = g.generic_fn_name(exp_sym.info.concrete_types, fname)
 			}
+			// Do not allocate for `Interface(unsafe{nil})` casts
+			is_nil_cast := expr is ast.UnsafeExpr && expr.expr is ast.Nil
+			if is_nil_cast {
+				g.write('/*nili*/')
+				g.write('((void*)0)')
+				return
+			}
 			g.call_cfn_for_casting_expr(fname, expr, expected_is_ptr, exp_styp, got_is_ptr,
 				false, got_styp)
 		}
diff --git a/vlib/v/parser/tmpl.v b/vlib/v/parser/tmpl.v
index 31b3fb15cb..f3745c906b 100644
--- a/vlib/v/parser/tmpl.v
+++ b/vlib/v/parser/tmpl.v
@@ -245,7 +245,9 @@ fn vweb_tmpl_${fn_name}() string {
 			// Remove new line byte
 			source.go_back(1)
 			source.writeln(parser.tmpl_str_end)
-			source.writeln(' } else { ')
+			pos := line.index('@else') or { continue }
+			source.writeln('}' + line[pos + 1..] + '{')
+			// source.writeln(' } else { ')
 			source.writeln(tmpl_str_start)
 			continue
 		}
@@ -332,7 +334,7 @@ fn vweb_tmpl_${fn_name}() string {
 		}
 
 		if pos := line.index('%') {
-			// %translation_key => ${tr('translation_key')}		
+			// %translation_key => ${tr('translation_key')}
 			mut line_ := line
 			if pos + 1 < line.len && line[pos + 1].is_letter() { //|| line[pos + 1] == '_' {
 				mut end := pos + 1
diff --git a/vlib/v/pref/pref.v b/vlib/v/pref/pref.v
index 161712752f..44b3aafff6 100644
--- a/vlib/v/pref/pref.v
+++ b/vlib/v/pref/pref.v
@@ -232,8 +232,9 @@ pub mut:
 	checker_match_exhaustive_cutoff_limit int = 12
 	thread_stack_size                     int = 8388608 // Change with `-thread-stack-size 4194304`. Note: on macos it was 524288, which is too small for more complex programs with many nested callexprs.
 	// wasm settings:
-	wasm_stack_top int = 1024 + (16 * 1024) // stack size for webassembly backend
-	wasm_validate  bool // validate webassembly code, by calling `wasm-validate`
+	wasm_stack_top    int = 1024 + (16 * 1024) // stack size for webassembly backend
+	wasm_validate     bool // validate webassembly code, by calling `wasm-validate`
+	warn_about_allocs bool // -warn-about-allocs warngs about every single allocation, e.g. 'hi $name'. Mostly for low level development where manual memory management is used.
 	// temp
 	// use_64_int bool
 }
@@ -504,6 +505,9 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 			'-sourcemap' {
 				res.sourcemap = true
 			}
+			'-warn-about-allocs' {
+				res.warn_about_allocs = true
+			}
 			'-sourcemap-src-included' {
 				res.sourcemap_src_included = true
 			}
diff --git a/vlib/v/slow_tests/valgrind/nil_interface.v b/vlib/v/slow_tests/valgrind/nil_interface.v
new file mode 100644
index 0000000000..8ec5c29f3c
--- /dev/null
+++ b/vlib/v/slow_tests/valgrind/nil_interface.v
@@ -0,0 +1,6 @@
+interface Resource {}
+
+fn main() {
+	mut resource := &Resource(unsafe { nil })
+	_ = resource
+}
diff --git a/vlib/veb/oauth/oauth.v b/vlib/veb/oauth/oauth.v
new file mode 100644
index 0000000000..114358202f
--- /dev/null
+++ b/vlib/veb/oauth/oauth.v
@@ -0,0 +1,63 @@
+module oauth
+
+import json
+import net.http
+
+pub enum TokenPostType {
+	form
+	json
+}
+
+pub struct Context {
+	token_url       string
+	client_id       string
+	client_secret   string
+	token_post_type TokenPostType = .form
+	redirect_uri    string
+}
+
+pub struct Request {
+pub:
+	client_id     string
+	client_secret string
+	code          string
+	state         string
+}
+
+pub fn (ctx &Context) get_token(code string) string {
+	oauth_request := Request{
+		client_id: ctx.client_id
+		client_secret: ctx.client_secret
+		code: code
+		//        state: csrf
+	}
+
+	js := json.encode(oauth_request)
+	if ctx.token_post_type == .json {
+		resp := http.post_json(ctx.token_url, js) or {
+			//        app.info(err.msg())
+
+			//        return app.redirect_to_index()
+			return ''
+		}
+		println('OAUTH RESPONSE ${resp}')
+		return resp.body
+	} else {
+		resp := http.post_form(ctx.token_url, {
+			'client_id':     ctx.client_id
+			'client_secret': ctx.client_secret
+			'code':          code
+			'grant_type':    'authorization_code'
+			//'scope':         bot
+			'redirect_uri':  ctx.redirect_uri
+		}) or {
+			//        app.info(err.msg())
+
+			//        return app.redirect_to_index()
+			return ''
+		}
+		println('OAUTH RESPONSE ${resp}')
+		return resp.body
+	}
+	return ''
+}
diff --git a/vlib/x/vweb/vweb.v b/vlib/x/vweb/vweb.v
index 58fc2468bb..b955a4340c 100644
--- a/vlib/x/vweb/vweb.v
+++ b/vlib/x/vweb/vweb.v
@@ -1,3 +1,4 @@
+//@[deprecated: '`x.vweb` is now `veb`. The module is no longer experimental.']
 module vweb
 
 import io