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Fix #788: Enum value used inside __traits(...) flagged as unused

This commit is contained in:
MoonlightSentinel 2020-01-26 18:41:58 +01:00
parent 241a38be1a
commit 4f417b64a1
1 changed files with 35 additions and 7 deletions
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42
src/dscanner/analysis/unused_variable.d
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@ -19,6 +19,12 @@ final class UnusedVariableCheck : UnusedIdentifierCheck
mixin AnalyzerInfo!"unused_variable_check";
/**
Ignore declarations which are allowed to be unused, e.g. inside of a
speculative compilation: __traits(compiles, { S s = 0; })
**/
uint ignoreDeclarations = 0;
/**
* Params:
* fileName = the name of the file being analyzed
@ -42,17 +48,30 @@ final class UnusedVariableCheck : UnusedIdentifierCheck
autoDeclaration.accept(this);
}
override void visit(const TraitsExpression traitsExp)
{
// issue #788: Enum values might be used inside of `__traits` expressions, e.g.:
// enum name = "abc";
// __traits(hasMember, S, name);
ignoreDeclarations++;
traitsExp.templateArgumentList.accept(this);
ignoreDeclarations--;
}
override protected void popScope()
{
foreach (uu; tree[$ - 1])
if (!ignoreDeclarations)
{
if (!uu.isRef && tree.length > 1)
foreach (uu; tree[$ - 1])
{
if (uu.uncertain)
continue;
immutable string errorMessage = "Variable " ~ uu.name ~ " is never used.";
addErrorMessage(uu.line, uu.column,
"dscanner.suspicious.unused_variable", errorMessage);
if (!uu.isRef && tree.length > 1)
{
if (uu.uncertain)
continue;
immutable string errorMessage = "Variable " ~ uu.name ~ " is never used.";
addErrorMessage(uu.line, uu.column,
"dscanner.suspicious.unused_variable", errorMessage);
}
}
}
tree = tree[0 .. $ - 1];
@ -124,6 +143,15 @@ final class UnusedVariableCheck : UnusedIdentifierCheck
testValue.writeln;
}
// Issue 788
void traits()
{
enum fieldName = "abc";
__traits(hasMember, S, fieldName);
__traits(compiles, { int i = 2; });
}
}c, sac);
stderr.writeln("Unittest for UnusedVariableCheck passed.");
}