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[Parse] Recover slightly better from bad shorthand if let #64566

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Merged
hamishknight merged 1 commit into from
Mar 23, 2023
Merged

[Parse] Recover slightly better from bad shorthand if let #64566

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10 changes: 10 additions & 0 deletions lib/Parse/ParseStmt.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1728,6 +1728,16 @@ Parser::parseStmtConditionElement(SmallVectorImpl<StmtConditionElement> &result,
auto diagLoc = ThePattern.get()->getSemanticsProvidingPattern()->getStartLoc();
diagnose(diagLoc, diag::conditional_var_valid_identifiers_only)
.fixItInsert(diagLoc, "<#identifier#> = ");

// For better recovery, assume the expression pattern as the initializer,
// and synthesize an optional AnyPattern.
auto *semanticPattern = ThePattern.get()->getSemanticsProvidingPattern();
if (auto *EP = dyn_cast<ExprPattern>(semanticPattern)) {
Init = makeParserResult(EP->getSubExpr());
auto *AP = AnyPattern::createImplicit(Context);
ThePattern =
makeParserResult(OptionalSomePattern::createImplicit(Context, AP));
}
} else {
diagnose(Tok, diag::conditional_var_initializer_required);
}
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15 changes: 12 additions & 3 deletions test/stmt/if_while_var.swift
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Expand Up @@ -42,8 +42,13 @@ if var nonOptional { nonOptional = nonOptionalStruct(); _ = nonOptional } // exp
guard let nonOptional else { _ = nonOptional; fatalError() } // expected-error{{initializer for conditional binding must have Optional type, not 'NonOptionalStruct'}}
guard var nonOptional else { _ = nonOptional; fatalError() } // expected-error{{initializer for conditional binding must have Optional type, not 'NonOptionalStruct'}}

if let nonOptional.property { } // expected-error{{unwrap condition requires a valid identifier}} expected-error{{pattern matching in a condition requires the 'case' keyword}}
if var nonOptional.property { } // expected-error{{unwrap condition requires a valid identifier}} expected-error{{pattern matching in a condition requires the 'case' keyword}}
if let nonOptional.property { }
// expected-error@-1 {{unwrap condition requires a valid identifier}}
// expected-error@-2 {{initializer for conditional binding must have Optional type, not 'Any'}}

if var nonOptional.property { }
// expected-error@-1 {{unwrap condition requires a valid identifier}}
// expected-error@-2 {{initializer for conditional binding must have Optional type, not 'Any'}}

guard let _ = nonOptionalStruct() else { fatalError() } // expected-error{{initializer for conditional binding must have Optional type, not 'NonOptionalStruct'}}
guard let _ = nonOptionalEnum() else { fatalError() } // expected-error{{initializer for conditional binding must have Optional type, not 'NonOptionalEnum'}}
Expand All @@ -65,7 +70,11 @@ class B {} // expected-note * {{did you mean 'B'?}}
class D : B {}// expected-note * {{did you mean 'D'?}}

// TODO poor recovery in these cases
if let {} // expected-error {{expected '{' after 'if' condition}} expected-error {{pattern matching in a condition requires the 'case' keyword}} expected-error {{unwrap condition requires a valid identifier}}
if let {}
// expected-error@-1 {{expected '{' after 'if' condition}}
// expected-error@-2 {{unwrap condition requires a valid identifier}}
// expected-error@-3 {{initializer for conditional binding must have Optional type, not '() -> ()'}}

if let x = { } // expected-error{{'{' after 'if'}} expected-error{{initializer for conditional binding must have Optional type, not '() -> ()'}}
// expected-warning@-1{{value 'x' was defined but never used}}

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