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cgen: fix optional functions with unused return values

pull/4116/head
Alexander Medvednikov 2020-03-25 23:57:22 +01:00
parent 89a05a474f
commit 25ee30d8cb
1 changed files with 19 additions and 3 deletions
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22
vlib/v/gen/cgen.v
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@ -598,6 +598,7 @@ fn (g mut Gen) gen_assign_stmt(assign_stmt ast.AssignStmt) {
g.expr(val)
}
}
g.expr_var_name = ''
}
g.writeln(';')
}
@ -2033,6 +2034,13 @@ fn (g mut Gen) gen_filter(node ast.MethodCallExpr) {
g.write(tmp)
}
fn (g mut Gen) insert_before(s string) {
cur_line := g.out.after(g.stmt_start_pos)
g.out.go_back(cur_line.len)
g.writeln(s)
g.write(cur_line)
}
fn (g mut Gen) call_expr(it ast.CallExpr) {
mut name := it.name
is_print := name == 'println'
@ -2082,10 +2090,18 @@ fn (g mut Gen) call_expr(it ast.CallExpr) {
}
if it.or_block.stmts.len > 0 {
// `foo() or { return }`
var_name := if g.expr_var_name != '' { g.expr_var_name } else { g.new_tmp_var() }
if g.expr_var_name == '' {
// The user is not using the optional return value. We need to use a temp var
// to access its fields (`.ok`, `.error` etc)
// `os.cp(...)` => `Option bool tmp = os__cp(...); if (!tmp.ok) { ... }`
styp := g.typ(it.return_type)
g.insert_before('$styp $var_name = ')
}
g.writeln(';') // or')
g.writeln('if (!${g.expr_var_name}.ok) {')
g.writeln('string err = ${g.expr_var_name}.v_error;')
g.writeln('int errcode = ${g.expr_var_name}.ecode;')
g.writeln('if ( !${var_name}.ok) {')
g.writeln('string err = ${var_name}.v_error;')
g.writeln('int errcode = ${var_name}.ecode;')
g.stmts(it.or_block.stmts)
g.writeln('}')
}