From 6dde9f76c617f8b09083d21dc20ae4091d410d15 Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Tue, 6 Jul 2021 14:40:20 +0300
Subject: [PATCH] cgen: reset g.tmp_count at the start of each fn (minimise v.c
 commit delta)

---
 vlib/v/gen/c/cgen.v | 8 +++++++-
 vlib/v/gen/c/fn.v   | 7 ++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index 175f75062f..98396b24c5 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -67,8 +67,9 @@ mut:
 	file                   &ast.File
 	fn_decl                &ast.FnDecl // pointer to the FnDecl we are currently inside otherwise 0
 	last_fn_c_name         string
-	tmp_count              int      // counter for unique tmp vars (_tmp1, tmp2 etc)
+	tmp_count              int      // counter for unique tmp vars (_tmp1, _tmp2 etc); resets at the start of each fn.
 	tmp_count2             int      // a separate tmp var counter for autofree fn calls
+	tmp_count_declarations int      // counter for unique tmp names (_d1, _d2 etc); does NOT reset, used for C declarations
 	is_assign_lhs          bool     // inside left part of assign expr (for array_set(), etc)
 	discard_or_result      bool     // do not safe last ExprStmt of `or` block in tmp variable to defer ongoing expr usage
 	is_void_expr_stmt      bool     // ExprStmt whos result is discarded
@@ -962,6 +963,11 @@ pub fn (mut g Gen) new_tmp_var() string {
 	return '_t$g.tmp_count'
 }
 
+pub fn (mut g Gen) new_tmp_declaration_name() string {
+	g.tmp_count_declarations++
+	return '_d$g.tmp_count_declarations'
+}
+
 pub fn (mut g Gen) current_tmp_var() string {
 	return '_t$g.tmp_count'
 }
diff --git a/vlib/v/gen/c/fn.v b/vlib/v/gen/c/fn.v
index f0097c9829..4b2375e7e5 100644
--- a/vlib/v/gen/c/fn.v
+++ b/vlib/v/gen/c/fn.v
@@ -332,6 +332,11 @@ fn (mut g Gen) gen_fn_decl(node &ast.FnDecl, skip bool) {
 	// we could be in an anon fn so save outer fn defer stmts
 	prev_defer_stmts := g.defer_stmts
 	g.defer_stmts = []
+	ctmp := g.tmp_count
+	g.tmp_count = 0
+	defer {
+		g.tmp_count = ctmp
+	}
 	g.stmts(node.stmts)
 	if node.is_noreturn {
 		g.writeln('\twhile(1);')
@@ -409,7 +414,7 @@ fn (mut g Gen) fn_args(args []ast.Param, is_variadic bool, scope &ast.Scope) ([]
 		g.write('void')
 	}
 	for i, arg in args {
-		mut caname := if arg.name == '_' { g.new_tmp_var() } else { c_name(arg.name) }
+		mut caname := if arg.name == '_' { g.new_tmp_declaration_name() } else { c_name(arg.name) }
 		typ := g.unwrap_generic(arg.typ)
 		arg_type_sym := g.table.get_type_symbol(typ)
 		mut arg_type_name := g.typ(typ) // util.no_dots(arg_type_sym.name)