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Differential D150783

[flang] Better error recovery for missing THEN in IF construct
ClosedPublic

Authored by klausler on May 17 2023, 8:01 AM.

Details

Reviewers
PeteSteinfeld
sscalpone
Commits
rG60b673023f54: [flang] Better error recovery for missing THEN in IF construct
Summary

Presented with "IF (...)" with no following tokens in the statement,
diagnose a missing "THEN" instead of complaining about all of the
possible action statement initial tokens that could have been there
for a non-construct IF statement.

Fixes https://github.com/llvm/llvm-project/issues/62299.

Diff Detail

Event Timeline

klausler created this revision.May 17 2023, 8:01 AM
Herald added a reviewer: sscalpone. · View Herald TranscriptMay 17 2023, 8:01 AM
Herald added a project: Restricted Project. · View Herald Transcript
Herald added subscribers: sunshaoce, jdoerfert. · View Herald Transcript
klausler requested review of this revision.May 17 2023, 8:01 AM
Harbormaster completed remote builds in B232614: Diff 523053.May 17 2023, 8:18 AM
PeteSteinfeld accepted this revision.May 17 2023, 8:57 AM

All builds and test correctly and looks good.

This revision is now accepted and ready to land.May 17 2023, 8:57 AM
Closed by commit rG60b673023f54: [flang] Better error recovery for missing THEN in IF construct (authored by klausler). · Explain WhyMay 18 2023, 11:41 AM
This revision was automatically updated to reflect the committed changes.
klausler added a commit: rG60b673023f54: [flang] Better error recovery for missing THEN in IF construct.

Revision Contents

PathSize
flang/
lib/
Parser/
3 lines
test/
Parser/
8 lines

Diff 523477

flang/lib/Parser/executable-parsers.cpp

Show First 20 Lines • Show All 299 Lines • ▼ Show 20 Lines
// R1135 if-then-stmt -> [if-construct-name :] IF ( scalar-logical-expr ) // R1135 if-then-stmt -> [if-construct-name :] IF ( scalar-logical-expr )
// THEN R1136 else-if-stmt -> // THEN R1136 else-if-stmt ->
// ELSE IF ( scalar-logical-expr ) THEN [if-construct-name] // ELSE IF ( scalar-logical-expr ) THEN [if-construct-name]
// R1137 else-stmt -> ELSE [if-construct-name] // R1137 else-stmt -> ELSE [if-construct-name]
// R1138 end-if-stmt -> END IF [if-construct-name] // R1138 end-if-stmt -> END IF [if-construct-name]
TYPE_CONTEXT_PARSER("IF construct"_en_US, TYPE_CONTEXT_PARSER("IF construct"_en_US,
construct<IfConstruct>( construct<IfConstruct>(
statement(construct<IfThenStmt>(maybe(name / ":"), statement(construct<IfThenStmt>(maybe(name / ":"),
"IF" >> parenthesized(scalarLogicalExpr) / "THEN")), "IF" >> parenthesized(scalarLogicalExpr) /
recovery("THEN"_tok, lookAhead(endOfStmt)))),
block, block,
many(construct<IfConstruct::ElseIfBlock>( many(construct<IfConstruct::ElseIfBlock>(
unambiguousStatement(construct<ElseIfStmt>( unambiguousStatement(construct<ElseIfStmt>(
"ELSE IF" >> parenthesized(scalarLogicalExpr), "ELSE IF" >> parenthesized(scalarLogicalExpr),
recovery("THEN"_tok, ok) >> maybe(name))), recovery("THEN"_tok, ok) >> maybe(name))),
block)), block)),
maybe(construct<IfConstruct::ElseBlock>( maybe(construct<IfConstruct::ElseBlock>(
statement(construct<ElseStmt>("ELSE" >> maybe(name))), block)), statement(construct<ElseStmt>("ELSE" >> maybe(name))), block)),
▲ Show 20 Lines • Show All 211 Lines • Show Last 20 Lines

flang/test/Parser/missing-then.f90

  • This file was added.
! RUN: not %flang_fc1 -fsyntax-only %s 2>&1 | FileCheck %s
!CHECK: expected 'THEN'
!CHECK-NOT: expected 'PAUSE'
if (.TRUE.)
!CHECK: expected 'THEN'
else if (.FALSE.)
end if
end