parser: filter out vet space indent errors inside StringInterLiterals (#9695)

cmd/tools/vvet/tests/indent_with_space.out

@@ -1,5 +1,6 @@
 cmd/tools/vvet/tests/indent_with_space.vv:2: error: Looks like you are using spaces for indentation.
 cmd/tools/vvet/tests/indent_with_space.vv:10: error: Looks like you are using spaces for indentation.
-cmd/tools/vvet/tests/indent_with_space.vv:16: error: Looks like you are using spaces for indentation.
+cmd/tools/vvet/tests/indent_with_space.vv:17: error: Looks like you are using spaces for indentation.
-cmd/tools/vvet/tests/indent_with_space.vv:19: error: Looks like you are using spaces for indentation.
+cmd/tools/vvet/tests/indent_with_space.vv:20: error: Looks like you are using spaces for indentation.
+cmd/tools/vvet/tests/indent_with_space.vv:22: error: Looks like you are using spaces for indentation.
 NB: You can run `v fmt -w file.v` to fix these errors automatically

cmd/tools/vvet/tests/indent_with_space.vv

@@ -13,8 +13,12 @@ fn block_comments() {
 }
 
 fn space_inside_strings() {
+	// Plain strings
   str := "Bad space usage for variable indentation.
   Here it's fine.
   Here too."
   str2 := 'linebreak and space\n  inside'
+	// String interpolation
+  si1 := 'Error here $foo
+  and not here'
 }

vlib/v/parser/parser.v

@@ -2322,6 +2322,17 @@ fn (mut p Parser) enum_val() ast.EnumVal {
 	}
 }
 
+fn (mut p Parser) filter_string_vet_errors(pos token.Position) {
+	if p.vet_errors.len == 0 {
+		return
+	}
+	p.vet_errors = p.vet_errors.filter(
+		(it.typ == .trailing_space && it.pos.line_nr - 1 >= pos.last_line)
+		|| (it.typ != .trailing_space && it.pos.line_nr - 1 > pos.last_line)
+		|| (it.typ == .space_indent && it.pos.line_nr - 1 <= pos.line_nr)
+		|| (it.typ != .space_indent && it.pos.line_nr - 1 < pos.line_nr))
+}
+
 fn (mut p Parser) string_expr() ast.Expr {
 	is_raw := p.tok.kind == .name && p.tok.lit == 'r'
 	is_cstr := p.tok.kind == .name && p.tok.lit == 'c'
@@ -2334,14 +2345,7 @@ fn (mut p Parser) string_expr() ast.Expr {
 	pos.last_line = pos.line_nr + val.count('\n')
 	if p.peek_tok.kind != .str_dollar {
 		p.next()
-		// Filter out false positive vet errors inside strings
+		p.filter_string_vet_errors(pos)
-		if p.vet_errors.len > 0 {
-			p.vet_errors = p.vet_errors.filter(
-				(it.typ == .trailing_space && it.pos.line_nr - 1 >= pos.last_line)
-				|| (it.typ != .trailing_space && it.pos.line_nr - 1 > pos.last_line)
-				|| (it.typ == .space_indent && it.pos.line_nr - 1 <= pos.line_nr)
-				|| (it.typ != .space_indent && it.pos.line_nr - 1 < pos.line_nr))
-		}
 		node = ast.StringLiteral{
 			val: val
 			is_raw: is_raw
@@ -2420,6 +2424,8 @@ fn (mut p Parser) string_expr() ast.Expr {
 		fills << fill
 		fposs << p.prev_tok.position()
 	}
+	pos = pos.extend(p.prev_tok.position())
+	p.filter_string_vet_errors(pos)
 	node = ast.StringInterLiteral{
 		vals: vals
 		exprs: exprs
@@ -2430,7 +2436,7 @@ fn (mut p Parser) string_expr() ast.Expr {
 		fills: fills
 		fmts: fmts
 		fmt_poss: fposs
-		pos: pos.extend(p.prev_tok.position())
+		pos: pos
 	}
 	// need_fmts: prelimery - until checker finds out if really needed
 	p.inside_str_interp = false

vlib/v/scanner/scanner.v

@@ -1094,9 +1094,12 @@ fn (mut s Scanner) ident_string() string {
 	// }
 	mut n_cr_chars := 0
 	mut start := s.pos
-	if s.text[start] == s.quote
+	start_char := s.text[start]
-		|| (s.text[start] == s.inter_quote && (s.is_inter_start || s.is_enclosed_inter)) {
+	if start_char == s.quote
+		|| (start_char == s.inter_quote && (s.is_inter_start || s.is_enclosed_inter)) {
 		start++
+	} else if start_char == `\n` {
+		s.inc_line_number()
 	}
 	s.is_inside_string = false
 	mut u_escapes_pos := []int{} // pos list of \uXXXX