checker,gen: introduce if match branch's id (#25308)

vlib/v/ast/ast.v

@@ -1248,6 +1248,7 @@ pub mut:
 	cond  Expr
 	stmts []Stmt
 	scope &Scope = unsafe { nil }
+	id    int
 }
 
 pub struct UnsafeExpr {
@@ -1298,6 +1299,7 @@ pub mut:
 	stmts []Stmt // right side
 	exprs []Expr // left side
 	scope &Scope = unsafe { nil }
+	id    int
 }
 
 pub struct SelectExpr {

vlib/v/checker/checker.v

@@ -102,6 +102,7 @@ pub mut:
 	ct_cond_stack               []ast.Expr
 	ct_user_defines             map[string]bool
 	ct_system_defines           map[string]bool
+	cur_ct_id                   int // id counter for $if $match branches
 mut:
 	stmt_level int // the nesting level inside each stmts list;
 	// .stmt_level is used to check for `evaluated but not used` ExprStmts like `1 << 1`

vlib/v/checker/if.v

@@ -107,9 +107,14 @@ fn (mut c Checker) if_expr(mut node ast.IfExpr) ast.Type {
 			if node.is_comptime {
 				// `idx_str` is composed of two parts:
 				// The first part represents the current context of the branch statement, `comptime_branch_context_str`, formatted like `T=int,X=string,method.name=json`
-				// The second part indicates the branch's location in the source file.
+				// The second part is the branch's id.
 				// This format must match what is in `cgen`.
-				idx_str := comptime_branch_context_str + '|${c.file.path}|${branch.cond.pos()}|'
+				if branch.id == 0 {
+					// this is a new branch, alloc a new id for it
+					c.cur_ct_id++
+					branch.id = c.cur_ct_id
+				}
+				idx_str := comptime_branch_context_str + '|id=${branch.id}|'
 				c.comptime.inside_comptime_if = true
 				mut sb := strings.new_builder(256)
 				comptime_if_result, comptime_if_multi_pass_branch = c.comptime_if_cond(mut branch.cond, mut
@@ -165,7 +170,12 @@ fn (mut c Checker) if_expr(mut node ast.IfExpr) ast.Type {
 					comptime_remove_curr_branch_stmts = true
 				}
 				// hack: as a `else` has no `cond`, so we use `branch.pos` here
-				idx_str := comptime_branch_context_str + '|${c.file.path}|${branch.pos}|'
+				if branch.id == 0 {
+					// this is a new branch, alloc a new id for it
+					c.cur_ct_id++
+					branch.id = c.cur_ct_id
+				}
+				idx_str := comptime_branch_context_str + '|id=${branch.id}|'
 				c.table.comptime_is_true[idx_str] = ast.ComptTimeCondResult{
 					val:   comptime_if_result
 					c_str: ''

vlib/v/checker/match.v

@@ -130,9 +130,14 @@ fn (mut c Checker) match_expr(mut node ast.MatchExpr) ast.Type {
 		if node.is_comptime {
 			// `idx_str` is composed of two parts:
 			// The first part represents the current context of the branch statement, `comptime_branch_context_str`, formatted like `T=int,X=string,method.name=json`
-			// The second part indicates the branch's location in the source file.
+			// The second part is the branch's id.
 			// This format must match what is in `cgen`.
-			idx_str := comptime_branch_context_str + '|${c.file.path}|${branch.pos}|'
+			if branch.id == 0 {
+				// this is a new branch, alloc a new id for it
+				c.cur_ct_id++
+				branch.id = c.cur_ct_id
+			}
+			idx_str := comptime_branch_context_str + '|id=${branch.id}|'
 			mut c_str := ''
 			if !branch.is_else {
 				if c.inside_x_matches_type {

vlib/v/gen/c/cgen.v

@@ -5810,11 +5810,7 @@ fn (mut g Gen) gen_hash_stmts(mut sb strings.Builder, node &ast.HashStmtNode, se
 			mut comptime_branch_context_str := g.gen_branch_context_string()
 			mut is_true := ast.ComptTimeCondResult{}
 			for i, branch in node.branches {
-				idx_str := if branch.cond.pos() == token.Pos{} {
-					comptime_branch_context_str + '|${g.file.path}|${branch.pos}|'
-				} else {
-					comptime_branch_context_str + '|${g.file.path}|${branch.cond.pos()}|'
-				}
+				idx_str := comptime_branch_context_str + '|id=${branch.id}|'
 				if comptime_is_true := g.table.comptime_is_true[idx_str] {
 					// `g.table.comptime_is_true` are the branch condition results set by `checker`
 					is_true = comptime_is_true

vlib/v/gen/c/comptime.v

@@ -5,7 +5,6 @@ module c
 
 import os
 import v.ast
-import v.token
 import v.util
 import v.pref
 import v.type_resolver
@@ -418,13 +417,9 @@ fn (mut g Gen) comptime_if(node ast.IfExpr) {
 		start_pos := g.out.len
 		// `idx_str` is composed of two parts:
 		// The first part represents the current context of the branch statement, `comptime_branch_context_str`, formatted like `T=int,X=string,method.name=json`
-		// The second part indicates the branch's location in the source file.
+		// The second part is the branch's id.
 		// This format must match what is in `checker`.
-		idx_str := if branch.cond.pos() == token.Pos{} {
-			comptime_branch_context_str + '|${g.file.path}|${branch.pos}|'
-		} else {
-			comptime_branch_context_str + '|${g.file.path}|${branch.cond.pos()}|'
-		}
+		idx_str := comptime_branch_context_str + '|id=${branch.id}|'
 		if comptime_is_true := g.table.comptime_is_true[idx_str] {
 			// `g.table.comptime_is_true` are the branch condition results set by `checker`
 			is_true = comptime_is_true
@@ -984,9 +979,9 @@ fn (mut g Gen) comptime_match(node ast.MatchExpr) {
 	for i, branch in node.branches {
 		// `idx_str` is composed of two parts:
 		// The first part represents the current context of the branch statement, `comptime_branch_context_str`, formatted like `T=int,X=string,method.name=json`
-		// The second part indicates the branch's location in the source file.
+		// The second part is the branch's id.
 		// This format must match what is in `checker`.
-		idx_str := comptime_branch_context_str + '|${g.file.path}|${branch.pos}|'
+		idx_str := comptime_branch_context_str + '|id=${branch.id}|'
 		if comptime_is_true := g.table.comptime_is_true[idx_str] {
 			// `g.table.comptime_is_true` are the branch condition results set by `checker`
 			is_true = comptime_is_true

vlib/v/gen/js/comptime.v

@@ -1,6 +1,5 @@
 module js
 
-import v.token
 import v.ast
 
 fn (mut g JsGen) gen_branch_context_string() string {
@@ -30,11 +29,7 @@ fn (mut g JsGen) comptime_if(node ast.IfExpr) {
 	mut comptime_branch_context_str := g.gen_branch_context_string()
 	mut is_true := ast.ComptTimeCondResult{}
 	for i, branch in node.branches {
-		idx_str := if branch.cond.pos() == token.Pos{} {
-			comptime_branch_context_str + '|${g.file.path}|${branch.pos}|'
-		} else {
-			comptime_branch_context_str + '|${g.file.path}|${branch.cond.pos()}|'
-		}
+		idx_str := comptime_branch_context_str + '|id=${branch.id}|'
 		if comptime_is_true := g.table.comptime_is_true[idx_str] {
 			is_true = comptime_is_true
 		} else {