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Only warn when float literals underflow to zero #154

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Merged
merged 1 commit into from
Nov 23, 2022
Merged

Only warn when float literals underflow to zero #154

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14 changes: 10 additions & 4 deletions src/parse_stream.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -865,20 +865,26 @@ function validate_literal_tokens(stream::ParseStream)
# parse_int_literal
# parse_uint_literal
elseif k == K"Float" || k == K"Float32"
underflow0 = false
if k == K"Float"
_, code = parse_float_literal(Float64, text, fbyte, nbyte)
x, code = parse_float_literal(Float64, text, fbyte, nbyte)
# jl_strtod_c can return "underflow" even for valid cases such
# as `5e-324` where the source is an exact representation of
# `x`. So only warn when underflowing to zero.
underflow0 = code == :underflow && x == 0
else
_, code = parse_float_literal(Float32, text, fbyte, nbyte)
x, code = parse_float_literal(Float32, text, fbyte, nbyte)
underflow0 = code == :underflow && x == 0
end
if code == :ok
# pass
elseif code == :overflow
emit_diagnostic(stream, fbyte, lbyte,
error="overflow in floating point literal")
had_error = true
elseif code == :underflow
elseif underflow0
emit_diagnostic(stream, fbyte, lbyte,
warning="underflow in floating point literal")
warning="underflow to zero in floating point literal")
end
elseif k == K"Char"
@assert fbyte < nbyte # Already handled in the parser
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8 changes: 6 additions & 2 deletions test/diagnostics.jl
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Expand Up @@ -16,9 +16,13 @@ end
@test diagnostic("x = 10.0f1000;") ==
Diagnostic(5, 13, :error, "overflow in floating point literal")
@test diagnostic("x = 10.0e-1000;") ==
Diagnostic(5, 14, :warning, "underflow in floating point literal")
Diagnostic(5, 14, :warning, "underflow to zero in floating point literal")
@test diagnostic("x = 10.0f-1000;") ==
Diagnostic(5, 14, :warning, "underflow in floating point literal")
Diagnostic(5, 14, :warning, "underflow to zero in floating point literal")
# Underflow boundary
@test diagnostic("5e-324", allow_multiple=true) == []
@test diagnostic("2e-324") ==
Diagnostic(1, 6, :warning, "underflow to zero in floating point literal")

# Char
@test diagnostic("x = ''") ==
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