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Add suggestion to remove if in let...else block

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Adds an additional hint to failures where we encounter an else keyword
while we're parsing an if-let block.

This is likely that the user has accidentally mixed if-let and let...else
together.
This commit is contained in:
Edward Shen 2023-01-23 20:31:45 -08:00 • committed by Edward Shen
parent c8e6a9e8b6
commit a8b77cfe54
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GPG key ID: D6A2AC5596760EE9
6 changed files with 61 additions and 14 deletions
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33
compiler/rustc_parse/src/parser/expr.rs
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@ -11,15 +11,15 @@ use crate::errors::{
ComparisonOrShiftInterpretedAsGenericSugg, DoCatchSyntaxRemoved, DotDotDot, EqFieldInit,
ExpectedElseBlock, ExpectedEqForLetExpr, ExpectedExpressionFoundLet,
FieldExpressionWithGeneric, FloatLiteralRequiresIntegerPart, FoundExprWouldBeStmt,
IfExpressionMissingCondition, IfExpressionMissingThenBlock, IfExpressionMissingThenBlockSub,
InvalidBlockMacroSegment, InvalidComparisonOperator, InvalidComparisonOperatorSub,
InvalidInterpolatedExpression, InvalidLiteralSuffixOnTupleIndex, InvalidLogicalOperator,
InvalidLogicalOperatorSub, LabeledLoopInBreak, LeadingPlusNotSupported, LeftArrowOperator,
LifetimeInBorrowExpression, MacroInvocationWithQualifiedPath, MalformedLoopLabel,
MatchArmBodyWithoutBraces, MatchArmBodyWithoutBracesSugg, MissingCommaAfterMatchArm,
MissingDotDot, MissingInInForLoop, MissingInInForLoopSub, MissingSemicolonBeforeArray,
NoFieldsForFnCall, NotAsNegationOperator, NotAsNegationOperatorSub,
OuterAttributeNotAllowedOnIfElse, ParenthesesWithStructFields,
IfExpressionLetSomeSub, IfExpressionMissingCondition, IfExpressionMissingThenBlock,
IfExpressionMissingThenBlockSub, InvalidBlockMacroSegment, InvalidComparisonOperator,
InvalidComparisonOperatorSub, InvalidInterpolatedExpression, InvalidLiteralSuffixOnTupleIndex,
InvalidLogicalOperator, InvalidLogicalOperatorSub, LabeledLoopInBreak, LeadingPlusNotSupported,
LeftArrowOperator, LifetimeInBorrowExpression, MacroInvocationWithQualifiedPath,
MalformedLoopLabel, MatchArmBodyWithoutBraces, MatchArmBodyWithoutBracesSugg,
MissingCommaAfterMatchArm, MissingDotDot, MissingInInForLoop, MissingInInForLoopSub,
MissingSemicolonBeforeArray, NoFieldsForFnCall, NotAsNegationOperator,
NotAsNegationOperatorSub, OuterAttributeNotAllowedOnIfElse, ParenthesesWithStructFields,
RequireColonAfterLabeledExpression, ShiftInterpretedAsGeneric, StructLiteralNotAllowedHere,
StructLiteralNotAllowedHereSugg, TildeAsUnaryOperator, UnexpectedIfWithIf,
UnexpectedTokenAfterLabel, UnexpectedTokenAfterLabelSugg, WrapExpressionInParentheses,
@ -2251,9 +2251,10 @@ impl<'a> Parser<'a> {
if let ExprKind::Block(_, None) = right.kind => {
self.sess.emit_err(IfExpressionMissingThenBlock {
if_span: lo,
sub: IfExpressionMissingThenBlockSub::UnfinishedCondition(
cond_span.shrink_to_lo().to(*binop_span)
),
missing_then_block_sub:
IfExpressionMissingThenBlockSub::UnfinishedCondition(cond_span.shrink_to_lo().to(*binop_span)),
let_else_sub: None,
});
std::mem::replace(right, this.mk_expr_err(binop_span.shrink_to_hi()))
},
@ -2279,9 +2280,15 @@ impl<'a> Parser<'a> {
if let Some(block) = recover_block_from_condition(self) {
block
} else {
let let_else_sub = matches!(cond.kind, ExprKind::Let(..))
.then(|| IfExpressionLetSomeSub { if_span: lo });
self.sess.emit_err(IfExpressionMissingThenBlock {
if_span: lo,
sub: IfExpressionMissingThenBlockSub::AddThenBlock(cond_span.shrink_to_hi()),
missing_then_block_sub: IfExpressionMissingThenBlockSub::AddThenBlock(
cond_span.shrink_to_hi(),
),
let_else_sub,
});
self.mk_block_err(cond_span.shrink_to_hi())
}