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Improve parsing of invalid expressions. (#2726)

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This addresses crashes for infix operator expressions, but the approach should more generally yield balanced parsed trees.
This commit is contained in:
Jon Ross-Perkins
2023-03-31 20:51:59 -07:00
committed by GitHub
parent 7824e9618c
commit a905cdea30
8 changed files with 74 additions and 13 deletions
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toolchain/parser/parse_node_kind.def
+3
View File
@@ -43,6 +43,9 @@
// The end of the file.
CARBON_PARSE_NODE_KIND_CHILD_COUNT(FileEnd, 0)
// An invalid expression. Used to balance the parse tree. Always has an error.
CARBON_PARSE_NODE_KIND_CHILD_COUNT(InvalidExpression, 0)
// An empty declaration, such as `;`.
CARBON_PARSE_NODE_KIND_CHILD_COUNT(EmptyDeclaration, 0)
toolchain/parser/parser.cpp
+3
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@@ -959,6 +959,9 @@ auto Parser::HandleExpressionInPostfixState() -> void {
break;
}
default: {
// Add a node to keep the parse tree balanced.
AddLeafNode(ParseNodeKind::InvalidExpression, *position_,
/*has_error=*/true);
CARBON_DIAGNOSTIC(ExpectedExpression, Error, "Expected expression.");
emitter_->Emit(*position_, ExpectedExpression);
ReturnErrorOnState();
toolchain/parser/testdata/if/fail_errors.carbon
Vendored
+7 -5
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@@ -17,10 +17,11 @@
// CHECK:STDOUT: {kind: 'CodeBlock', text: '}', subtree_size: 2},
// CHECK:STDOUT: {kind: 'IfStatement', text: 'if', subtree_size: 6},
// CHECK:STDOUT: {kind: 'IfConditionStart', text: '('},
// CHECK:STDOUT: {kind: 'IfCondition', text: ')', has_error: yes, subtree_size: 2},
// CHECK:STDOUT: {kind: 'InvalidExpression', text: ')', has_error: yes},
// CHECK:STDOUT: {kind: 'IfCondition', text: ')', has_error: yes, subtree_size: 3},
// CHECK:STDOUT: {kind: 'CodeBlockStart', text: '{'},
// CHECK:STDOUT: {kind: 'CodeBlock', text: '}', subtree_size: 2},
// CHECK:STDOUT: {kind: 'IfStatement', text: 'if', subtree_size: 5},
// CHECK:STDOUT: {kind: 'IfStatement', text: 'if', subtree_size: 6},
// CHECK:STDOUT: {kind: 'IfConditionStart', text: '('},
// CHECK:STDOUT: {kind: 'NameReference', text: 'b'},
// CHECK:STDOUT: {kind: 'IfCondition', text: ')', has_error: yes, subtree_size: 3},
@@ -31,9 +32,10 @@
// CHECK:STDOUT: {kind: 'NameReference', text: 'd'},
// CHECK:STDOUT: {kind: 'IfCondition', text: ')', subtree_size: 3},
// CHECK:STDOUT: {kind: 'CodeBlockStart', text: '}', has_error: yes},
// CHECK:STDOUT: {kind: 'CodeBlock', text: '}', has_error: yes, subtree_size: 2},
// CHECK:STDOUT: {kind: 'IfStatement', text: 'if', subtree_size: 6},
// CHECK:STDOUT: {kind: 'FunctionDefinition', text: '}', subtree_size: 29},
// CHECK:STDOUT: {kind: 'InvalidExpression', text: '}', has_error: yes},
// CHECK:STDOUT: {kind: 'CodeBlock', text: '}', has_error: yes, subtree_size: 3},
// CHECK:STDOUT: {kind: 'IfStatement', text: 'if', subtree_size: 7},
// CHECK:STDOUT: {kind: 'FunctionDefinition', text: '}', subtree_size: 31},
// CHECK:STDOUT: {kind: 'FileEnd', text: ''},
// CHECK:STDOUT: ]
toolchain/parser/testdata/operators/fail_invalid_infix.carbon
Vendored
+44
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@@ -0,0 +1,44 @@
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
// AUTOUPDATE
// RUN: %{not} %{carbon-run-parser}
// CHECK:STDOUT: [
// CHECK:STDOUT: {kind: 'VariableIntroducer', text: 'var'},
// CHECK:STDOUT: {kind: 'DeclaredName', text: 'a'},
// CHECK:STDOUT: {kind: 'Literal', text: 'i32'},
// CHECK:STDOUT: {kind: 'PatternBinding', text: ':', subtree_size: 3},
// CHECK:STDOUT: {kind: 'VariableInitializer', text: '='},
// CHECK:STDOUT: {kind: 'NameReference', text: 'n'},
// CHECK:STDOUT: {kind: 'InvalidExpression', text: ';', has_error: yes},
// CHECK:STDOUT: {kind: 'InfixOperator', text: '==', has_error: yes, subtree_size: 3},
// CHECK:STDOUT: {kind: 'VariableDeclaration', text: ';', subtree_size: 9},
// CHECK:STDOUT: {kind: 'VariableIntroducer', text: 'var'},
// CHECK:STDOUT: {kind: 'DeclaredName', text: 'b'},
// CHECK:STDOUT: {kind: 'Literal', text: 'i32'},
// CHECK:STDOUT: {kind: 'PatternBinding', text: ':', subtree_size: 3},
// CHECK:STDOUT: {kind: 'VariableInitializer', text: '='},
// CHECK:STDOUT: {kind: 'InvalidExpression', text: '==', has_error: yes},
// CHECK:STDOUT: {kind: 'NameReference', text: 'n'},
// CHECK:STDOUT: {kind: 'InfixOperator', text: '==', has_error: yes, subtree_size: 3},
// CHECK:STDOUT: {kind: 'VariableDeclaration', text: ';', subtree_size: 9},
// CHECK:STDOUT: {kind: 'VariableIntroducer', text: 'var'},
// CHECK:STDOUT: {kind: 'DeclaredName', text: 'c'},
// CHECK:STDOUT: {kind: 'Literal', text: 'i32'},
// CHECK:STDOUT: {kind: 'PatternBinding', text: ':', subtree_size: 3},
// CHECK:STDOUT: {kind: 'VariableInitializer', text: '='},
// CHECK:STDOUT: {kind: 'InvalidExpression', text: '==', has_error: yes},
// CHECK:STDOUT: {kind: 'InvalidExpression', text: ';', has_error: yes},
// CHECK:STDOUT: {kind: 'InfixOperator', text: '==', has_error: yes, subtree_size: 3},
// CHECK:STDOUT: {kind: 'VariableDeclaration', text: ';', subtree_size: 9},
// CHECK:STDOUT: {kind: 'FileEnd', text: ''},
// CHECK:STDOUT: ]
// CHECK:STDERR: {{.*}}/toolchain/parser/testdata/operators/fail_invalid_infix.carbon:[[@LINE+1]]:19: Expected expression.
var a: i32 = n == ;
// CHECK:STDERR: {{.*}}/toolchain/parser/testdata/operators/fail_invalid_infix.carbon:[[@LINE+1]]:14: Expected expression.
var b: i32 = == n;
// CHECK:STDERR: {{.*}}/toolchain/parser/testdata/operators/fail_invalid_infix.carbon:[[@LINE+2]]:14: Expected expression.
// CHECK:STDERR: {{.*}}/toolchain/parser/testdata/operators/fail_invalid_infix.carbon:[[@LINE+1]]:17: Expected expression.
var c: i32 = == ;
toolchain/parser/testdata/return/fail_no_semi.carbon
Vendored
+3 -2
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@@ -11,8 +11,9 @@
// CHECK:STDOUT: {kind: 'ParameterList', text: ')', subtree_size: 2},
// CHECK:STDOUT: {kind: 'FunctionDefinitionStart', text: '{', subtree_size: 5},
// CHECK:STDOUT: {kind: 'ReturnStatementStart', text: 'return'},
// CHECK:STDOUT: {kind: 'ReturnStatement', text: 'return', has_error: yes, subtree_size: 2},
// CHECK:STDOUT: {kind: 'FunctionDefinition', text: '}', subtree_size: 8},
// CHECK:STDOUT: {kind: 'InvalidExpression', text: '}', has_error: yes},
// CHECK:STDOUT: {kind: 'ReturnStatement', text: 'return', has_error: yes, subtree_size: 3},
// CHECK:STDOUT: {kind: 'FunctionDefinition', text: '}', subtree_size: 9},
// CHECK:STDOUT: {kind: 'FileEnd', text: ''},
// CHECK:STDOUT: ]
toolchain/parser/testdata/struct/fail_missing_type.carbon
Vendored
+4 -3
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@@ -10,13 +10,14 @@
// CHECK:STDOUT: {kind: 'StructLiteralOrStructTypeLiteralStart', text: '{'},
// CHECK:STDOUT: {kind: 'DesignatedName', text: 'a'},
// CHECK:STDOUT: {kind: 'StructFieldDesignator', text: '.', subtree_size: 2},
// CHECK:STDOUT: {kind: 'InvalidExpression', text: '}', has_error: yes},
// CHECK:STDOUT: {kind: 'StructFieldUnknown', text: ':', has_error: yes},
// CHECK:STDOUT: {kind: 'StructTypeLiteral', text: '}', subtree_size: 5},
// CHECK:STDOUT: {kind: 'PatternBinding', text: ':', subtree_size: 7},
// CHECK:STDOUT: {kind: 'StructTypeLiteral', text: '}', subtree_size: 6},
// CHECK:STDOUT: {kind: 'PatternBinding', text: ':', subtree_size: 8},
// CHECK:STDOUT: {kind: 'VariableInitializer', text: '='},
// CHECK:STDOUT: {kind: 'StructLiteralOrStructTypeLiteralStart', text: '{'},
// CHECK:STDOUT: {kind: 'StructLiteral', text: '}', subtree_size: 2},
// CHECK:STDOUT: {kind: 'VariableDeclaration', text: ';', subtree_size: 12},
// CHECK:STDOUT: {kind: 'VariableDeclaration', text: ';', subtree_size: 13},
// CHECK:STDOUT: {kind: 'FileEnd', text: ''},
// CHECK:STDOUT: ]
toolchain/parser/testdata/struct/fail_missing_value.carbon
Vendored
+4 -3
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@@ -10,13 +10,14 @@
// CHECK:STDOUT: {kind: 'StructLiteralOrStructTypeLiteralStart', text: '{'},
// CHECK:STDOUT: {kind: 'DesignatedName', text: 'a'},
// CHECK:STDOUT: {kind: 'StructFieldDesignator', text: '.', subtree_size: 2},
// CHECK:STDOUT: {kind: 'InvalidExpression', text: '}', has_error: yes},
// CHECK:STDOUT: {kind: 'StructFieldUnknown', text: '=', has_error: yes},
// CHECK:STDOUT: {kind: 'StructLiteral', text: '}', subtree_size: 5},
// CHECK:STDOUT: {kind: 'PatternBinding', text: ':', subtree_size: 7},
// CHECK:STDOUT: {kind: 'StructLiteral', text: '}', subtree_size: 6},
// CHECK:STDOUT: {kind: 'PatternBinding', text: ':', subtree_size: 8},
// CHECK:STDOUT: {kind: 'VariableInitializer', text: '='},
// CHECK:STDOUT: {kind: 'StructLiteralOrStructTypeLiteralStart', text: '{'},
// CHECK:STDOUT: {kind: 'StructLiteral', text: '}', subtree_size: 2},
// CHECK:STDOUT: {kind: 'VariableDeclaration', text: ';', subtree_size: 12},
// CHECK:STDOUT: {kind: 'VariableDeclaration', text: ';', subtree_size: 13},
// CHECK:STDOUT: {kind: 'FileEnd', text: ''},
// CHECK:STDOUT: ]
toolchain/semantics/semantics_parse_tree_handler.cpp
+6
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@@ -732,6 +732,12 @@ auto SemanticsParseTreeHandler::HandleInterfaceIntroducer(
return false;
}
auto SemanticsParseTreeHandler::HandleInvalidExpression(
ParseTree::Node parse_node) -> bool {
emitter_->Emit(parse_node, SemanticsTodo, "HandleInvalidExpression");
return false;
}
auto SemanticsParseTreeHandler::HandleLiteral(ParseTree::Node parse_node)
-> bool {
auto token = parse_tree_->node_token(parse_node);