parser: improve token detection and error messages for unexpected EOF…

…s, add tests (#21110)

vlib/v/checker/tests/like_operator_outside_orm_error.out

@@ -1,4 +1,4 @@
-vlib/v/checker/tests/like_operator_outside_orm_error.vv:4:15: error: unexpected name `like`, expecting `,`
+vlib/v/checker/tests/like_operator_outside_orm_error.vv:4:15: error: only `c`, `r`, `js` are recognized string prefixes, but you tried to use `like`
     2 |     name := 'Luke'
     3 | 
     4 |     println(name like 'L%')

vlib/v/parser/fn.v

@@ -23,7 +23,7 @@ fn (mut p Parser) call_expr(language ast.Language, mod string) ast.CallExpr {
 		'JS.${name}'
 	} else if language == .wasm {
 		'WASM.${name}'
-	} else if mod.len > 0 {
+	} else if mod != '' {
 		'${mod}.${name}'
 	} else {
 		name
@@ -52,8 +52,23 @@ fn (mut p Parser) call_expr(language ast.Language, mod string) ast.CallExpr {
 	}
 	p.check(.lpar)
 	args := p.call_args()
+	if p.tok.kind != .rpar {
+		params := p.table.fns[fn_name] or { unsafe { p.table.fns['${p.mod}.${fn_name}'] } }.params
+		if args.len < params.len && p.prev_tok.kind != .comma {
+			p.unexpected_with_pos(p.prev_tok.pos(), expecting: '`,`')
+		} else if args.len > params.len {
+			ok_arg_pos := (args[params.len - 1] or { args[0] }).pos
+			pos := token.Pos{
+				...ok_arg_pos
+				col: ok_arg_pos.col + ok_arg_pos.len
+			}
+			p.unexpected_with_pos(pos.extend(p.tok.pos()), expecting: '`)`')
+		} else {
+			p.unexpected_with_pos(p.prev_tok.pos(), expecting: '`)`')
+		}
+	}
 	last_pos := p.tok.pos()
-	p.check(.rpar)
+	p.next()
 	mut pos := first_pos.extend(last_pos)
 	mut or_stmts := []ast.Stmt{} // TODO: remove unnecessary allocations by just using .absent
 	mut or_pos := p.tok.pos()
@@ -104,11 +119,9 @@ fn (mut p Parser) call_args() []ast.CallArg {
 		p.inside_call_args = prev_inside_call_args
 	}
 	mut args := []ast.CallArg{}
-	start_pos := p.tok.pos()
-	for p.tok.kind != .rpar {
+	for p.tok.kind != .rpar && p.tok.kind != .comma {
 		if p.tok.kind == .eof {
-			p.error_with_pos('unexpected eof reached, while parsing call argument', start_pos)
-			return []
+			return args
 		}
 		is_shared := p.tok.kind == .key_shared
 		is_atomic := p.tok.kind == .key_atomic
@@ -149,8 +162,8 @@ fn (mut p Parser) call_args() []ast.CallArg {
 			comments: comments
 			pos: pos
 		}
-		if p.tok.kind != .rpar {
-			p.check(.comma)
+		if p.tok.kind == .comma {
+			p.next()
 		}
 	}
 	return args

vlib/v/parser/tests/fn_call_unexpected_eof_comma_multi_arg_err.out

@@ -0,0 +1,6 @@
+vlib/v/parser/tests/fn_call_unexpected_eof_comma_multi_arg_err.vv:5:14: error: unexpected eof, expecting `,`
+    3 | fn foo(i i64, s string) {}
+    4 | 
+    5 | foo(time.now()
+      |              ^
+    6 |

vlib/v/parser/tests/fn_call_unexpected_eof_comma_multi_arg_err.vv

@@ -0,0 +1,6 @@
+import time
+
+fn foo(i i64, s string) {}
+
+foo(time.now()
+

vlib/v/parser/tests/fn_call_unexpected_eof_rpar_after_fn_arg_err.out

@@ -0,0 +1,6 @@
+vlib/v/parser/tests/fn_call_unexpected_eof_rpar_after_fn_arg_err.vv:3:36: error: unexpected eof, expecting `)`
+    1 | import os
+    2 | 
+    3 | println(os.file_last_mod_unix('x.v')
+      |                                    ^
+    4 |

vlib/v/parser/tests/fn_call_unexpected_eof_rpar_after_fn_arg_err.vv

@@ -0,0 +1,4 @@
+import os
+
+println(os.file_last_mod_unix('x.v')
+

vlib/v/parser/tests/fn_call_unexpected_eof_rpar_err.out

@@ -0,0 +1,4 @@
+vlib/v/parser/tests/fn_call_unexpected_eof_rpar_err.vv:1:12: error: unexpected eof, expecting `)`
+    1 | println('a',
+      |            ^
+    2 |

vlib/v/parser/tests/fn_call_unexpected_eof_rpar_err.vv

@@ -0,0 +1,2 @@
+println('a',
+

vlib/v/parser/tests/fn_call_unexpected_eof_rpar_multi_arg_too_many_err.out

@@ -0,0 +1,6 @@
+vlib/v/parser/tests/fn_call_unexpected_eof_rpar_multi_arg_too_many_err.vv:5:22: error: unexpected eof, expecting `)`
+    3 | fn foo(i i64, s string) {}
+    4 | 
+    5 | foo(time.now(), 'foo',
+      |                      ^
+    6 |

vlib/v/parser/tests/fn_call_unexpected_eof_rpar_multi_arg_too_many_err.vv

@@ -0,0 +1,6 @@
+import time
+
+fn foo(i i64, s string) {}
+
+foo(time.now(), 'foo',
+

vlib/v/parser/tests/fn_call_unexpected_eof_rpar_multi_line_err.out

@@ -0,0 +1,5 @@
+vlib/v/parser/tests/fn_call_unexpected_eof_rpar_multi_line_err.vv:1:14: error: unexpected eof, expecting `)`
+    1 | println('foo' bar
+      |              ~~~~
+    2 | println('baz')
+    3 |

vlib/v/parser/tests/fn_call_unexpected_eof_rpar_multi_line_err.vv

@@ -0,0 +1,3 @@
+println('foo' bar
+println('baz')
+

vlib/v/parser/tests/fn_call_unexpected_eof_rpar_too_many_err.out

@@ -0,0 +1,4 @@
+vlib/v/parser/tests/fn_call_unexpected_eof_rpar_too_many_err.vv:1:12: error: unexpected eof, expecting `)`
+    1 | println('a', 'b'
+      |            ~~~~~
+    2 |

vlib/v/parser/tests/fn_call_unexpected_eof_rpar_too_many_err.vv

@@ -0,0 +1,2 @@
+println('a', 'b'
+