[DebugInfo] Remove conflicting debug info in switch

For address-only types, a temporary was emitted with the same debug variable
and same scope as the instruction it is moved to after entering a shared case,
but it would have a different type, which would create a conflict.
The better way to fix this would probably to use a different scope for both,
but the variable is moved immediately anyway.

Author: Snowy1803

lib/SILGen/SILGenPattern.cpp

@@ -2867,7 +2867,12 @@ void PatternMatchEmission::emitAddressOnlyAllocations() {
       if (!ty.isAddressOnly(SGF.F))
         continue;
       assert(!Temporaries[vd]);
-      Temporaries[vd] = SGF.emitTemporaryAllocation(vd, ty);
+      // Don't generate debug info for the temporary, as another debug_value
+      // will be created in the body, with the same scope and a different type
+      // Not sure if this is the best way to avoid that?
+      Temporaries[vd] = SGF.emitTemporaryAllocation(
+        vd, ty, DoesNotHaveDynamicLifetime, IsNotLexical, IsNotFromVarDecl,
+        /* generateDebugInfo = */ false);
     }
   }
 

test/SILGen/switch.swift

@@ -1461,9 +1461,9 @@ func testVoidType() {
 
 // CHECK-LABEL: sil hidden [ossa] @$s6switch28addressOnlyFallthroughCalleeyyAA015MultipleAddressC8CaseEnumOyxGSzRzlF : $@convention(thin) <T where T : BinaryInteger> (@in_guaranteed MultipleAddressOnlyCaseEnum<T>) -> () {
 // CHECK: bb0([[ARG:%.*]] :
-// CHECK:   [[AB_PHI:%.*]] = alloc_stack $T, let, name "x"
-// CHECK:   [[ABB_PHI:%.*]] = alloc_stack $T, let, name "x"
-// CHECK:   [[ABBC_PHI:%.*]] = alloc_stack $T, let, name "x"
+// CHECK:   [[AB_PHI:%.*]] = alloc_stack $T
+// CHECK:   [[ABB_PHI:%.*]] = alloc_stack $T
+// CHECK:   [[ABBC_PHI:%.*]] = alloc_stack $T
 // CHECK:   [[SWITCH_ENUM_ARG:%.*]] = alloc_stack $MultipleAddressOnlyCaseEnum<T>
 // CHECK:   copy_addr [[ARG]] to [init] [[SWITCH_ENUM_ARG]]
 // CHECK:   switch_enum_addr [[SWITCH_ENUM_ARG]] : $*MultipleAddressOnlyCaseEnum<T>, case #MultipleAddressOnlyCaseEnum.a!enumelt: [[BB_A:bb[0-9]+]], case #MultipleAddressOnlyCaseEnum.b!enumelt: [[BB_B:bb[0-9]+]], case #MultipleAddressOnlyCaseEnum.c!enumelt: [[BB_C:bb[0-9]+]]