diff --git a/crates/syntax/src/validation.rs b/crates/syntax/src/validation.rs index 8dc47e0bd3..3ea5844c95 100644 --- a/crates/syntax/src/validation.rs +++ b/crates/syntax/src/validation.rs @@ -38,6 +38,7 @@ pub(crate) fn validate(root: &SyntaxNode) -> Vec { ast::PtrType(it) => validate_trait_object_ptr_ty(it, &mut errors), ast::FnPtrType(it) => validate_trait_object_fn_ptr_ret_ty(it, &mut errors), ast::MacroRules(it) => validate_macro_rules(it, &mut errors), + ast::LetExpr(it) => validate_let_expr(it, &mut errors), _ => (), } } @@ -343,3 +344,33 @@ fn validate_const(const_: ast::Const, errors: &mut Vec) { errors.push(SyntaxError::new("const globals cannot be mutable", mut_token.text_range())); } } + +fn validate_let_expr(let_: ast::LetExpr, errors: &mut Vec) { + let mut token = let_.syntax().clone(); + loop { + token = match token.parent() { + Some(it) => it, + None => break, + }; + + if ast::ParenExpr::can_cast(token.kind()) { + continue; + } else if let Some(it) = ast::BinExpr::cast(token.clone()) { + if it.op_kind() == Some(ast::BinaryOp::LogicOp(ast::LogicOp::And)) { + continue; + } + } else if ast::IfExpr::can_cast(token.kind()) + || ast::WhileExpr::can_cast(token.kind()) + || ast::MatchGuard::can_cast(token.kind()) + { + // It must be part of the condition since the expressions are inside a block. + return; + } + + break; + } + errors.push(SyntaxError::new( + "`let` expressions are not supported here", + let_.syntax().text_range(), + )); +} diff --git a/crates/syntax/test_data/parser/validation/invalid_let_expr.rast b/crates/syntax/test_data/parser/validation/invalid_let_expr.rast new file mode 100644 index 0000000000..5b37b59783 --- /dev/null +++ b/crates/syntax/test_data/parser/validation/invalid_let_expr.rast @@ -0,0 +1,216 @@ +SOURCE_FILE@0..282 + FN@0..281 + FN_KW@0..2 "fn" + WHITESPACE@2..3 " " + NAME@3..6 + IDENT@3..6 "foo" + PARAM_LIST@6..8 + L_PAREN@6..7 "(" + R_PAREN@7..8 ")" + WHITESPACE@8..9 " " + BLOCK_EXPR@9..281 + STMT_LIST@9..281 + L_CURLY@9..10 "{" + WHITESPACE@10..15 "\n " + CONST@15..42 + CONST_KW@15..20 "const" + WHITESPACE@20..21 " " + UNDERSCORE@21..22 "_" + COLON@22..23 ":" + WHITESPACE@23..24 " " + TUPLE_TYPE@24..26 + L_PAREN@24..25 "(" + R_PAREN@25..26 ")" + WHITESPACE@26..27 " " + EQ@27..28 "=" + WHITESPACE@28..29 " " + LET_EXPR@29..41 + LET_KW@29..32 "let" + WHITESPACE@32..33 " " + WILDCARD_PAT@33..34 + UNDERSCORE@33..34 "_" + WHITESPACE@34..35 " " + EQ@35..36 "=" + WHITESPACE@36..37 " " + PATH_EXPR@37..41 + PATH@37..41 + PATH_SEGMENT@37..41 + NAME_REF@37..41 + IDENT@37..41 "None" + SEMICOLON@41..42 ";" + WHITESPACE@42..48 "\n\n " + LET_STMT@48..83 + LET_KW@48..51 "let" + WHITESPACE@51..52 " " + WILDCARD_PAT@52..53 + UNDERSCORE@52..53 "_" + WHITESPACE@53..54 " " + EQ@54..55 "=" + WHITESPACE@55..56 " " + IF_EXPR@56..82 + IF_KW@56..58 "if" + WHITESPACE@58..59 " " + LITERAL@59..63 + TRUE_KW@59..63 "true" + WHITESPACE@63..64 " " + BLOCK_EXPR@64..82 + STMT_LIST@64..82 + L_CURLY@64..65 "{" + WHITESPACE@65..66 " " + PAREN_EXPR@66..80 + L_PAREN@66..67 "(" + LET_EXPR@67..79 + LET_KW@67..70 "let" + WHITESPACE@70..71 " " + WILDCARD_PAT@71..72 + UNDERSCORE@71..72 "_" + WHITESPACE@72..73 " " + EQ@73..74 "=" + WHITESPACE@74..75 " " + PATH_EXPR@75..79 + PATH@75..79 + PATH_SEGMENT@75..79 + NAME_REF@75..79 + IDENT@75..79 "None" + R_PAREN@79..80 ")" + WHITESPACE@80..81 " " + R_CURLY@81..82 "}" + SEMICOLON@82..83 ";" + WHITESPACE@83..89 "\n\n " + IF_EXPR@89..279 + IF_KW@89..91 "if" + WHITESPACE@91..92 " " + BIN_EXPR@92..114 + LITERAL@92..96 + TRUE_KW@92..96 "true" + WHITESPACE@96..97 " " + AMP2@97..99 "&&" + WHITESPACE@99..100 " " + PAREN_EXPR@100..114 + L_PAREN@100..101 "(" + LET_EXPR@101..113 + LET_KW@101..104 "let" + WHITESPACE@104..105 " " + WILDCARD_PAT@105..106 + UNDERSCORE@105..106 "_" + WHITESPACE@106..107 " " + EQ@107..108 "=" + WHITESPACE@108..109 " " + PATH_EXPR@109..113 + PATH@109..113 + PATH_SEGMENT@109..113 + NAME_REF@109..113 + IDENT@109..113 "None" + R_PAREN@113..114 ")" + WHITESPACE@114..115 " " + BLOCK_EXPR@115..279 + STMT_LIST@115..279 + L_CURLY@115..116 "{" + WHITESPACE@116..125 "\n " + EXPR_STMT@125..140 + PAREN_EXPR@125..139 + L_PAREN@125..126 "(" + LET_EXPR@126..138 + LET_KW@126..129 "let" + WHITESPACE@129..130 " " + WILDCARD_PAT@130..131 + UNDERSCORE@130..131 "_" + WHITESPACE@131..132 " " + EQ@132..133 "=" + WHITESPACE@133..134 " " + PATH_EXPR@134..138 + PATH@134..138 + PATH_SEGMENT@134..138 + NAME_REF@134..138 + IDENT@134..138 "None" + R_PAREN@138..139 ")" + SEMICOLON@139..140 ";" + WHITESPACE@140..149 "\n " + WHILE_EXPR@149..273 + WHILE_KW@149..154 "while" + WHITESPACE@154..155 " " + LET_EXPR@155..167 + LET_KW@155..158 "let" + WHITESPACE@158..159 " " + WILDCARD_PAT@159..160 + UNDERSCORE@159..160 "_" + WHITESPACE@160..161 " " + EQ@161..162 "=" + WHITESPACE@162..163 " " + PATH_EXPR@163..167 + PATH@163..167 + PATH_SEGMENT@163..167 + NAME_REF@163..167 + IDENT@163..167 "None" + WHITESPACE@167..168 " " + BLOCK_EXPR@168..273 + STMT_LIST@168..273 + L_CURLY@168..169 "{" + WHITESPACE@169..182 "\n " + MATCH_EXPR@182..263 + MATCH_KW@182..187 "match" + WHITESPACE@187..188 " " + PATH_EXPR@188..192 + PATH@188..192 + PATH_SEGMENT@188..192 + NAME_REF@188..192 + IDENT@188..192 "None" + WHITESPACE@192..193 " " + MATCH_ARM_LIST@193..263 + L_CURLY@193..194 "{" + WHITESPACE@194..211 "\n " + MATCH_ARM@211..249 + WILDCARD_PAT@211..212 + UNDERSCORE@211..212 "_" + WHITESPACE@212..213 " " + MATCH_GUARD@213..228 + IF_KW@213..215 "if" + WHITESPACE@215..216 " " + LET_EXPR@216..228 + LET_KW@216..219 "let" + WHITESPACE@219..220 " " + WILDCARD_PAT@220..221 + UNDERSCORE@220..221 "_" + WHITESPACE@221..222 " " + EQ@222..223 "=" + WHITESPACE@223..224 " " + PATH_EXPR@224..228 + PATH@224..228 + PATH_SEGMENT@224..228 + NAME_REF@224..228 + IDENT@224..228 "None" + WHITESPACE@228..229 " " + FAT_ARROW@229..231 "=>" + WHITESPACE@231..232 " " + BLOCK_EXPR@232..249 + STMT_LIST@232..249 + L_CURLY@232..233 "{" + WHITESPACE@233..234 " " + LET_STMT@234..247 + LET_KW@234..237 "let" + WHITESPACE@237..238 " " + WILDCARD_PAT@238..239 + UNDERSCORE@238..239 "_" + WHITESPACE@239..240 " " + EQ@240..241 "=" + WHITESPACE@241..242 " " + PATH_EXPR@242..246 + PATH@242..246 + PATH_SEGMENT@242..246 + NAME_REF@242..246 + IDENT@242..246 "None" + SEMICOLON@246..247 ";" + WHITESPACE@247..248 " " + R_CURLY@248..249 "}" + WHITESPACE@249..262 "\n " + R_CURLY@262..263 "}" + WHITESPACE@263..272 "\n " + R_CURLY@272..273 "}" + WHITESPACE@273..278 "\n " + R_CURLY@278..279 "}" + WHITESPACE@279..280 "\n" + R_CURLY@280..281 "}" + WHITESPACE@281..282 "\n" +error 29..41: `let` expressions are not supported here +error 67..79: `let` expressions are not supported here +error 126..138: `let` expressions are not supported here diff --git a/crates/syntax/test_data/parser/validation/invalid_let_expr.rs b/crates/syntax/test_data/parser/validation/invalid_let_expr.rs new file mode 100644 index 0000000000..1515ae5334 --- /dev/null +++ b/crates/syntax/test_data/parser/validation/invalid_let_expr.rs @@ -0,0 +1,14 @@ +fn foo() { + const _: () = let _ = None; + + let _ = if true { (let _ = None) }; + + if true && (let _ = None) { + (let _ = None); + while let _ = None { + match None { + _ if let _ = None => { let _ = None; } + } + } + } +}