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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Swift Framework returns 'ambiguous use of' method extension in lldb"
href="https://bugs.llvm.org/show_bug.cgi?id=44579">44579</a>
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<th>Summary</th>
<td>Swift Framework returns 'ambiguous use of' method extension in lldb
</td>
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<th>Product</th>
<td>lldb
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>MacOS X
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>All Bugs
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<th>Assignee</th>
<td>lldb-dev@lists.llvm.org
</td>
</tr>
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<th>Reporter</th>
<td>alexis.lefevre@yahoo.com
</td>
</tr>
<tr>
<th>CC</th>
<td>jdevlieghere@apple.com, llvm-bugs@lists.llvm.org
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<pre>Hi,
lldb-1100.0.28.19
Apple Swift version 5.1 (swiftlang-1100.0.270.13 clang-1100.0.33.7)
I've upgraded to Xcode 11 & swift 5, and hit an an issue with method extensions
when they are made available through a framework. More specifically, in a
project structured like this:
-> Main Project
-> Framework created from sources in 'Main Project'
-> Subproject using the above Framework (Sources packaged in the framework are
not visible to the sub-project)
Everything compiles and runs fine, but when running debug sessions on the
subproject, all extensions in 'Framework' return error: ambiguous use of when
invoked from the lldb command line. Here is a code sample to give an idea:
Create a macOs command line project, and add a new target, 'MagicFramework',
and in a file Spells.swift (make sure the file is visible to Main &
MagicFramework)
import Foundation
extension String {
public func castSpell() -> String {
return "✨ " + self
}
}
Then create a subproject 'Wizard', and in a file wizard.swift (visible to
Wizard only):
import Foundation
import MagicFramework
public class Tadaa {
public func magic(spell:String) -> String {
return spell.castSpell()
}
}
in Wizard's main.swift file, add:
import Foundation
let aa = Tadaa().magic(spell: "this is magic")
print(aa)
You should have the following structure:
-> Main project
----> MagicFramework
----> Wizard subproject
then build&run 'Wizard' sub, with a break point on spell.castSpell() in Tadaa.
At the lldb prompt, type:
(lldb)po spell.castSpell()
error: <EXPR>:3:1: error: ambiguous use of 'castSpell()'
spell.castSpell()
However:
(lldb) image lookup -vn castSpell
1 match found in
/Users/lameyl01/Library/Developer/Xcode/DerivedData/Main-dsjbnoyousgzmrdnqxtxoeyeyzpv/Build/Products/Debug/MagicFramework.framework/Versions/A/MagicFramework:
Address: MagicFramework[0x0000000000000ab0]
(MagicFramework.__TEXT.__text + 0)
Summary: MagicFramework`(extension in
MagicFramework):Swift.String.castSpell() -> Swift.String at Spells.swift:12
Module: file =
"/Users/lameyl01/Library/Developer/Xcode/DerivedData/Main-dsjbnoyousgzmrdnqxtxoeyeyzpv/Build/Products/Debug/MagicFramework.framework/Versions/A/MagicFramework",
arch = "x86_64"
CompileUnit: id = {0x00000000}, file =
"/Users/lameyl01/tmp/Main/MagicFramework/Spells.swift", language = "swift"
Function: id = {0x100000038}, name = "(extension in
MagicFramework):Swift.String.castSpell() -> Swift.String", mangled =
"$sSS14MagicFrameworkE9castSpellSSyF", range =
[0x000000010033fab0-0x000000010033fb21)
FuncType: id = {0x100000038}, byte-size = 8, decl = Spells.swift:12,
compiler_type = "() -> ()"
Blocks: id = {0x100000038}, range = [0x10033fab0-0x10033fb21)
LineEntry: [0x000000010033fab0-0x000000010033fabf):
/Users/lameyl01/tmp/Main/MagicFramework/Spells.swift:12
Symbol: id = {0x00000005}, range =
[0x000000010033fab0-0x000000010033fb21), name="(extension in
MagicFramework):Swift.String.castSpell() -> Swift.String",
mangled="$sSS14MagicFrameworkE9castSpellSSyF"
Variable: id = {0x100000055}, name = "self", type = "Swift.String",
location = DW_OP_fbreg(-16), decl = Spells.swift:12
So that means that lldb has found exactly one match: The extension in the
MagicFramework library. So there is no reason why this should be ambiguous.
For the sake of completeness I also checked the type of the variable spell as
llbd sees it:
(lldb) frame variable spell
(String) spell = "this is magic"
So to summarize: lldb knows the type is String. It knows that there is a
function castSpell defined in the extension and it knows of exactly one
implementation of said function. But still it shows the error message.
So unless I'm missing something essential here, this must be a lldb bug.
from source:
<a href="https://stackoverflow.com/questions/58705591/swift-framework-returns-ambiguous-use-of-method-extension-in-lldb">https://stackoverflow.com/questions/58705591/swift-framework-returns-ambiguous-use-of-method-extension-in-lldb</a></pre>
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