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Turn semicolon as empty statement into an error #15072

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Merged
RazvanN7 merged 1 commit into from
Apr 4, 2023
Merged

Turn semicolon as empty statement into an error #15072

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21 changes: 21 additions & 0 deletions changelog/dmd.empty-statement-error.dd
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Original file line number Diff line number Diff line change
@@ -0,0 +1,21 @@
Using `;` as an empty statement has been turned into an error

This has been deprecated since 2.075.0 because it's error prone:

---
void main()
{
foreach (i; 0 .. 8);
{
// Because of the accidental semicolon above,
// this block statement is executed once.
// It's not the loop body
}
}
---

It will now result in an error.
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@WalterBright WalterBright Jun 13, 2023

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It always has resulted in an error.

@dkorpel ??

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@dkorpel dkorpel Jun 13, 2023

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The changelog's example is wrong, you can see the new error in the diff of the test file.


$(CONSOLE
app.d(3): Error: use `{ }` for an empty statement, not `;`
)
12 changes: 6 additions & 6 deletions compiler/src/dmd/cparse.d
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Original file line number Diff line number Diff line change
Expand Up @@ -199,7 +199,7 @@ final class CParser(AST) : Parser!AST
else if (token.value == TOK.leftCurly)
s = cparseStatement(ParseStatementFlags.curly | ParseStatementFlags.scope_);
else
s = cparseStatement(ParseStatementFlags.semiOk);
s = cparseStatement(0);
s = new AST.LabelStatement(loc, ident, s);
break;
}
Expand Down Expand Up @@ -373,7 +373,7 @@ final class CParser(AST) : Parser!AST
auto statements = new AST.Statements();
while (token.value != TOK.rightCurly && token.value != TOK.endOfFile)
{
statements.push(cparseStatement(ParseStatementFlags.semi | ParseStatementFlags.curlyScope));
statements.push(cparseStatement(ParseStatementFlags.curlyScope));
}
if (endPtr)
*endPtr = token.ptr;
Expand Down Expand Up @@ -514,7 +514,7 @@ final class CParser(AST) : Parser!AST
auto statements = new AST.Statements();
while (token.value != TOK.case_ && token.value != TOK.default_ && token.value != TOK.endOfFile && token.value != TOK.rightCurly)
{
auto cur = cparseStatement(ParseStatementFlags.semi | ParseStatementFlags.curlyScope);
auto cur = cparseStatement(ParseStatementFlags.curlyScope);
statements.push(cur);

// https://issues.dlang.org/show_bug.cgi?id=21739
Expand All @@ -529,7 +529,7 @@ final class CParser(AST) : Parser!AST
}
else
{
s = cparseStatement(ParseStatementFlags.semi);
s = cparseStatement(0);
}
s = new AST.ScopeStatement(loc, s, token.loc);
s = new AST.CaseStatement(loc, exp, s);
Expand All @@ -546,12 +546,12 @@ final class CParser(AST) : Parser!AST
auto statements = new AST.Statements();
while (token.value != TOK.case_ && token.value != TOK.default_ && token.value != TOK.endOfFile && token.value != TOK.rightCurly)
{
statements.push(cparseStatement(ParseStatementFlags.semi | ParseStatementFlags.curlyScope));
statements.push(cparseStatement(ParseStatementFlags.curlyScope));
}
s = new AST.CompoundStatement(loc, statements);
}
else
s = cparseStatement(ParseStatementFlags.semi);
s = cparseStatement(0);
s = new AST.ScopeStatement(loc, s, token.loc);
s = new AST.DefaultStatement(loc, s);
break;
Expand Down
20 changes: 8 additions & 12 deletions compiler/src/dmd/parse.d
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Original file line number Diff line number Diff line change
Expand Up @@ -5198,7 +5198,7 @@ class Parser(AST, Lexer = dmd.lexer.Lexer) : Lexer
case TOK.leftCurly:
if (requireDo)
error("missing `do { ... }` after `in` or `out`");
f.fbody = parseStatement(ParseStatementFlags.semi);
f.fbody = parseStatement(0);
f.endloc = endloc;
break;

Expand Down Expand Up @@ -6034,7 +6034,7 @@ LagainStc:
auto statements = new AST.Statements();
while (token.value != TOK.rightCurly && token.value != TOK.endOfFile)
{
statements.push(parseStatement(ParseStatementFlags.semi | ParseStatementFlags.curlyScope));
statements.push(parseStatement(ParseStatementFlags.curlyScope));
}
if (endPtr)
*endPtr = token.ptr;
Expand Down Expand Up @@ -6067,10 +6067,7 @@ LagainStc:
case TOK.semicolon:
if (!(flags & ParseStatementFlags.semiOk))
{
if (flags & ParseStatementFlags.semi)
deprecation("use `{ }` for an empty statement, not `;`");
else
error("use `{ }` for an empty statement, not `;`");
error("use `{ }` for an empty statement, not `;`");
}
nextToken();
s = new AST.ExpStatement(loc, cast(AST.Expression)null);
Expand Down Expand Up @@ -6287,7 +6284,7 @@ LagainStc:
_body = null;
}
else
_body = parseStatement(ParseStatementFlags.semi);
_body = parseStatement(0);
s = new AST.PragmaStatement(loc, ident, args, _body);
break;
}
Expand Down Expand Up @@ -6340,7 +6337,7 @@ LagainStc:
auto statements = new AST.Statements();
while (token.value != TOK.case_ && token.value != TOK.default_ && token.value != TOK.endOfFile && token.value != TOK.rightCurly)
{
auto cur = parseStatement(ParseStatementFlags.semi | ParseStatementFlags.curlyScope);
auto cur = parseStatement(ParseStatementFlags.curlyScope);
statements.push(cur);

// https://issues.dlang.org/show_bug.cgi?id=21739
Expand All @@ -6355,7 +6352,7 @@ LagainStc:
}
else
{
s = parseStatement(ParseStatementFlags.semi);
s = parseStatement(0);
}
s = new AST.ScopeStatement(loc, s, token.loc);

Expand Down Expand Up @@ -6384,12 +6381,12 @@ LagainStc:
auto statements = new AST.Statements();
while (token.value != TOK.case_ && token.value != TOK.default_ && token.value != TOK.endOfFile && token.value != TOK.rightCurly)
{
statements.push(parseStatement(ParseStatementFlags.semi | ParseStatementFlags.curlyScope));
statements.push(parseStatement(ParseStatementFlags.curlyScope));
}
s = new AST.CompoundStatement(loc, statements);
}
else
s = parseStatement(ParseStatementFlags.semi);
s = parseStatement(0);
s = new AST.ScopeStatement(loc, s, token.loc);
s = new AST.DefaultStatement(loc, s);
break;
Expand Down Expand Up @@ -9686,7 +9683,6 @@ immutable PREC[EXP.max + 1] precedence =

enum ParseStatementFlags : int
{
semi = 1, // empty ';' statements are allowed, but deprecated
scope_ = 2, // start a new scope
curly = 4, // { } statement is required
curlyScope = 8, // { } starts a new scope
Expand Down
2 changes: 1 addition & 1 deletion compiler/src/dmd/statementsem.d
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Expand Up @@ -4788,7 +4788,7 @@ private Statements* flatten(Statement statement, Scope* sc)
auto a = new Statements();
while (p.token.value != TOK.endOfFile)
{
Statement s = p.parseStatement(ParseStatementFlags.semi | ParseStatementFlags.curlyScope);
Statement s = p.parseStatement(ParseStatementFlags.curlyScope);
if (!s || global.errors != errors)
return errorStatements();
a.push(s);
Expand Down
8 changes: 4 additions & 4 deletions compiler/test/fail_compilation/fail4559.d
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@@ -1,10 +1,10 @@
/*
REQUIRED_ARGS: -o- -de
REQUIRED_ARGS:
TEST_OUTPUT:
---
fail_compilation/fail4559.d(13): Deprecation: use `{ }` for an empty statement, not `;`
fail_compilation/fail4559.d(19): Deprecation: use `{ }` for an empty statement, not `;`
fail_compilation/fail4559.d(21): Deprecation: use `{ }` for an empty statement, not `;`
fail_compilation/fail4559.d(13): Error: use `{ }` for an empty statement, not `;`
fail_compilation/fail4559.d(19): Error: use `{ }` for an empty statement, not `;`
fail_compilation/fail4559.d(21): Error: use `{ }` for an empty statement, not `;`
---
*/

Expand Down